Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

A comparison of the effects of an investigative-based and a traditional laboratory program on students’… McCarthy, Thomas Andrew 1983

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1983_A8 M23.pdf [ 6.1MB ]
Metadata
JSON: 831-1.0055316.json
JSON-LD: 831-1.0055316-ld.json
RDF/XML (Pretty): 831-1.0055316-rdf.xml
RDF/JSON: 831-1.0055316-rdf.json
Turtle: 831-1.0055316-turtle.txt
N-Triples: 831-1.0055316-rdf-ntriples.txt
Original Record: 831-1.0055316-source.json
Full Text
831-1.0055316-fulltext.txt
Citation
831-1.0055316.ris

Full Text

A COMPARISON OF THE EFFECTS OF AN INVESTIGATIVE-BASED AND A TRADITIONAL LABORATORY PROGRAM ON STUDENTS' UNDERSTANDING OF THE PROCESS OF SCIENCE by THOMAS ANDREW MCCARTHY B.SC, THE UNIVERSITY OF BRITISH COLUMBIA, 1974 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in THE FACULTY OF GRADUATE STUDIES Department of Mathematics and Science Education We accept this Thesis as conforming to the required standard The University of B r i t i s h Columbia A p r i l 1983 © Thomas Andrew McCarthy, 1983 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I agree t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by t h e head o f my department o r by h i s o r her r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f Education The U n i v e r s i t y o f B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date PlfR/C^ f?^^ DE-6 (3/81) ABSTRACT PURPOSE OF THE STUDY The purpose of this study was to compare the effectiveness of two approaches to laboratory work in changing student understanding of the processes of science. An author-designed investigative-based laboratory approach was compared to a t r a d i t i o n a l laboratory method as outlined in conventional laboratory manual texts. This investigation was undertaken to provide empirical data concerning the effectiveness of an approach used in teaching laboratory work during the past fiv e years. The study was carried out in a senior high school in the B.C. Lower Mainland. PROCEDURE The sample consisted of 41 students enrolled in two blocks of the author's Biology 12 classes. One block was the control group, assigned to use the t r a d i t i o n a l laboratory approach and the other was the experimental group assigned to be exposed to the investigative-based laboratory approach. The experimental phase of this study took place over the f i r s t three months of the calender year 1983. The students in both groups were pretested using the Welch Science Process Inventory (SPI) instrument during the f i r s t week of the study. Following exposure to treatment, the students were posttested using the same SPI instrument. i i Data obtained from the instrument was analyzed using analysis of covariance with the posttest as the c r i t e r i o n v ariable. The F values obtained from this analysis were compared with the c r i t i c a l F values that were required for significance at the 0.05 l e v e l . FINDINGS From the analysis of data, i t was found from the adjusted posttest means, that there was a s i g n i f i c a n t difference between the laboratory groups with respect to an understanding of the process of science. S p e c i f i c a l l y , the in v e s t i g a t i v e -based laboratory group was found to have a s t a t i s t i c a l l y s i g n i f i c a n t l y greater understanding of the process of science than the t r a d i t i o n a l laboratory group. CONCLUSIONS Although i t was concluded that the experimental group possessed a s i g n i f i c a n t l y greater understanding of the process of science, caution was suggested in attempting to generalize the application of the results of this study outside the l i m i t i n g confines of the study. Recommendations for further research were proposed. " i i i -TABLE OF CONTENTS Page ABSTRACT i i TABLE OF CONTENTS iv LIST OF TABLES v i i LIST OF FIGURES v i i i ACKNOWLEDGEMENTS ix CHAPTER 1 INTRODUCTION 1.0 The Problem 1 1.1 The Importance of the Problem 2 1.2 Hypothesis 5 CHAPTER 2 ~ REVIEW OF THE LITERATURE 2.0 Views on the Effectiveness of the Tradi t i o n a l Laboratory Instruction 7 2.1 Alternative Forms of Laboratory Instruction as Compared to more T r a d i t i o n a l Forms 13 2.1.1 Academic Achievement 14 2.1.2 Student Interest 15 2.1.3 C r i t i c a l Thinking and Reasoning A b i l i t y 16 2.1.4 Understanding the Nature and Process of Science 19 2.2 Measurement of Laboratory Research Study Outcomes.. 21 2.2.1 Watson-Glaser C r i t i c a l Thinking Appraisal.... 23 2.2.2 Test on Understanding Science 24 2.2.3 Welch Science Process Inventory 26 2.3 Summary 28 CHAPTER 3 ~ METHOD OF STUDY 3.0 Introduction 35 3.1 Population 35 iv Page 3.1.1 Description of Subjects 35 3.1.2 Selection of Subjects 36 3.2 Research Design 38 3.3 Evaluation Instrument 39 3.4 Procedural Details 40 3.4.1 Control Group A c t i v i t i e s 41 3.4.2 Experimental Group A c t i v i t i e s 42 3.5 Analysis Techniques 45 CHAPTER 4 - ANALYSIS OF DATA 4.0 Introduction 48 4.1 Description of Research Findings 48 4.1.1 Analysis of Co-Variance (Ancova) 50 4.1.2 F-Test Ratio 51 4.1.3 Regression Graphical Analysis 52 CHAPTER 5 ~ CONCLUSIONS, LIMITATIONS AND RECOMMENDATIONS 5.0 Introduction 54 5.1 Conclusions 55 5.2 Limitations 57 5.3 Recommendations 58 5.4 Epilogue 59 BIBLIOGRAPHY 61 Appendix A Sample l e t t e r s of Consent 68 Appendix B Overall Timetable of Events 71 Appendix C A c t i v i t i e s in the Control Group's Tr a d i t i o n a l Laboratory Program 73 Appendix D An Example of the process of S c i e n t i f i c Investigation 89 Appenix E A c t i v i t i e s in the Experimental Group's Investigative-Based Laboratory Program.... 93 - v -Appendix F Raw Scores for and T2 112 Appendix G Standard Deviation Graphs for and T2. 119 Appendix H Data Outlay for the Analysis of Covariance.. LIST OF TABLES Page TABLE 1. Summary of studies comparing the t r a d i t i o n a l laboratory method to an alternative laboratory method on measure of academic achievement 30 2. Summary of studies comparing the t r a d i t i o n a l laboratory method to an alternative laboratory method on measures of enhanced student interest in laboratory course of study 31 3. Summary of studies comparing the t r a d i t i o n a l laboratory method to an alternative laboratory method on measures of c r i t i c a l thinking and reasoning a b i l i t i e s 32 4 . Summary of studies comparing the t r a d i t i o n a l laboratroy method to an alternative laboratory method on measures of student understanding of the nature and process of science 33 5. Characteristics of classes 37 6. Data Outlay - T]_ 125 7. Data Outlay - T 2 126 8. Treatment Effects (ANCOVA) 51 9. Calculations of estimated posttest scores 52 - v i i -LIST OF FIGURES Page FIGURE 1. A n a l y s i s of p r e t e s t s c o r e s - c o n t r o l group 120 2. A n a l y s i s of p o s s t e s t s c o r e s - c o n t r o l group 121 3. A n a l y s i s of p r e t e s t s c o r e s - e x p e r i m e n t a l group. 122 4. A n a l y s i s of p o s t t e s t s c o r e s - e x p e r i m e n t a l group 123 5. Comparison of pre and p o s t t e s t s c o r e s -e x p e r i m e n t a l and c o n t r o l 49 6. Treatment r e g r e s s i o n l i n e s 53 - v i i i -ACKNOWLEDGMENT The w r i t e r i s indebted to Dr. R. C a r l i s l e , my major a d v i s o r , f o r encouragement and guidance i n the development t h i s study. Thanks are a l s o due to Dr. W. Bol d t f o r h i s advice and a i d i n s t a t i s t i c a l analyses and to Dr. F. Gornal I would a l s o l i k e to express my g r a t i t u d e to the ad m i n i s t r a t i o n , s t a f f and students of my Seni o r Secondary School f o r t h e i r c o o p e r a t i o n during the experimental stage of t h i s study. - 1 -CHAPTER I INTRODUCTION 1.0 THE PROBLEM The purpose of this study was to determine the r e l a t i v e effectiveness of two methods of teaching a senior high school laboratory biology program. Effectiveness was based on achievement of students' understandings of the process of science occurring during the course. The treatment examined in this study was an 'investigative-based' format wherein students were provided with an opportunity to develop their own hypothesis to a research problem, design and carry out an experiment, and discuss the outcomes of the experiment after analysis of data. The treatment was compared with a " t r a d i t i o n a l " laboratory format in which the students performed assigned exercises using a conventional laboratory manual. Comparison between the treatment and control groups was undertaken using the S.P.I. (Science Process Inventory), an instrument designed by Wayne Welch and Milton O. P e l l a (1968) from the University of Wisconsin. This instrument purports to measure student understanding of the process of science which Welch and Pe l l a (1968) derived from books by Beveridge, Conant, Kemeny, Lachman, Nash and Wilson (Welch, 1968, p.64). Elements of t h i s derived process were presented to fourteen research s c i e n t i s t s for v a l i d i t y judgment. The l i s t was then revised on the basis of suggestions from the s c i e n t i s t s . - 2 -S p e c i f i c a l l y , t h e n , t h e p r o b l e m may be s t a t e d as f o l l o w s : i s t h e r e any s i g n i f i c a n t d i f f e r e n c e i n s t u d e n t u n d e r s t a n d i n g o f t h e p r o c e s s o f s c i e n c e i n b i o l o g y t w e l v e c l a s s e s t h a t can be a t t r i b u t e d t o the e x p o s u r e o f s t u d e n t s t o i n v e s t i g a t i v e - b a s e d l a b o r a t o r y p r o c e d u r e s ? 1.1 I m p o r t a n c e o f t h e P r o b l e m The l a b o r a t o r y has l o n g been a d i s t i n c t i v e f e a t u r e o f s c i e n c e e d u c a t i o n . In 1970, t h e Commission o f P r o f e s s i o n a l S t a n d a r d s and P r a c t i c e s o f the N a t i o n a l S c i e n c e T e a c h e r ' s A s s o c i a t i o n t h o u g h t t h a t the c a s e f o r s c h o o l s c i e n c e l a b o r a t o r i e s was t o o o b v i o u s t o a r g u e (Ramsey & Howe, 1 9 6 9 ) : T h a t the e x p e r i e n c e p o s s i b l e f o r s t u d e n t s i n the l a b o r a t o r y s i t u a t i o n s h o u l d be an i n t e g r a l p a r t o f any s c i e n c e c o u r s e has come t o have a wide a c c e p t a n c e i n s c i e n c e t e a c h i n g . What the b e s t k i n d s o f e x p e r i e n c e s a r e , however, and how t h e s e may be b l e n d e d w i t h more c o n v e n t i o n a l c l a s s w o r k , has n o t been o b j e c t i v e l y e v a l u a t e d t o t h e e x t e n t t h a t c l e a r d i r e c t i o n b ased on r e s e a r c h i s a v a i l a b l e f o r t e a c h e r s ( p . 7 5 ) . L e s s t h a n t e n y e a r s l a t e r , the c a s e f o r the l a b o r a t o r y i n s c i e n c e i n s t r u c t i o n was n o t as s e l f - e v i d e n t as i t once seemed S c i e n c e l a b o r a t o r y r e q u i r e m e n t s a r e c u r r e n t l y o f s p e c i a l c o n c e r n b e c a u s e t h e r e i s now a t r e n d t o r e t r e a t from s t u d e n t - c e n t e r e d s c i e n c e a c t i v i t i e s , r e s u l t i n g i n l e s s t i m e and e x p e r i e n c e i n t h e s c i e n c e l a b o r a t o r y ( G a r d n e r , 1 9 7 9 ) . S c i e n c e e d u c a t o r s c o n t i n u e t o be d i s h e a r t e n e d by s t u d e n t s ' v i e w o f s c i e n c e as an a b s o l u t e e n d e a v o r - as i f i t - 3 -yields the whole truth and nothing but. Yet a large part of the reason for such a misconception may be our f a i l u r e to help students understand the process of science. Merely to provide students with d e f i n i t i o n s of terms l i k e "hypothesis" and "theory" w i l l not help them understand the subtle and complex aspects of testing an hypothesis. Too few laboratory courses o f f e r any sort of confrontation with the unknown. The student is expected to produce a v e r i f i c a t i o n of something he/she already knows. Instead of recording what actually occurs, he/she is trained to ask what a result is supposed to be. A student should be compelled to think through the bearing of his results on the possible conclusions. Such concerns may have prompted the following recommendation from the B r i t i s h Columbia Assessment contract team: That teachers of science at both the junior and senior secondary levels make a conscious e f f o r t to promote the development of s k i l l s such as designing experiments, and interpreting data, ... and an appreciation of the nature and methods of science (Hobbs, 1978, p.47). D i s s a t i s f a c t i o n with existing laboratory instruction has been expressed even by some who consider that time and money required for i n s t r u c t i o n a l laboratory work must be spent (Caplan & Fowler, 1968). "Cookbook" laboratory experiences, in which the student goes through the motions of experimental work without a concern for an understanding of the underlying p r i n c i p l e s , would not seem capable of providing meaningful - 4 -experiences for concept learning (Ausubel, 1964). A c t i v i t i e s which simply confirm what the textbook or teacher has already said also seem to be unprofitable (Anderson & Weigard, 1967; Hurd, 1964). Laboratory a c t i v i t i e s of these sorts involve the student primarily in manipulation of apparatus and data and require only minimal consideration by the student of the rationale for these operations and ce r t a i n l y do not convey an impression of s c i e n t i f i c research. Stake and Easley (1978) state the case rather poignantly by rela t i n g an anecdote from an actual classroom occurrence: "Seeing nothing but inky black in the beaker they asked, 'What's supposed to happen?' The g i r l at the next table said, 'Its supposed to go up and down,' so they a l l wrote, 'It went up and down,' in their lab reports" (p. 19 :6 ) . Having become d i s i l l u s i o n e d with the t r a d i t i o n a l method of laboratory instruction as exemplified in laboratory texts issued to science students, the author has experimented with an "investigative-based" laboratory format in his classroom. U n t i l the advent of this study, the opportunity has not arisen to empirically test the effectiveness of this alternate laboratory approach in terms of student understanding of the process of science. At this juncture the 'process of science' w i l l be expressed as this thesis demands that the process of science be measured to determine the effectiveness of experimental treatment. - 5 -Welch and Pe l l a (1968) do not stipulate in d e t a i l what students must demonstrate to indicate knowledge of the process of science. The author considers that for knowledge of the process of science students must demonstrate the a b i l i t y to: 1. make careful observations that lead to interpretations, explanations and predictions, 2. advance and formulate an hypothesis that is based on prio r observations or research and attempts to predict some future event, 3. devise experiments that test hypotheses and that are adequately controlled, 4. report results in the form of organized quantitative data tables and/or quali t a t i v e observations, 5. analyse data either by graph or s t a t i s t i c s , 6. draw inferences and discuss results from experimental data and analyses, 7. suggest further research or the creation of new hypotheses due to the in s u f f i c i e n c y of data or sources of error. 1.2 Hypothesis Because previous studies, in general together, do not provide d e f i n i t i v e results regarding the d i f f e r e n t i a l e f f e c t of an investigative-based laboratory program to a t r a d i t i o n a l laboratory program the research hypothesis is stated in n u l l form. - 6 -So comparing the t r a d i t i o n a l l a b o r a t o r y group and the i n v e s t i g a t i v e - b a s e d l a b o r a t o r y group: There i s no s i g n i f i c a n t i n c r e a s e i n s t u d e n t u n d e r s t a n d i n g o f the p r o c e s s of s c i e n c e t h a t can be a t t r i b u t e d to the exposure of s t u d e n t s to i n v e s t i g a t i v e - b a s e d l a b o r a t o r y p r o c e d u r e s . - 7 -CHAPTER 2 REVIEW OF THE LITERATURE 2.0 Views on the Effectiveness of T r a d i t i o n a l Laboratory Instruction The role of science laboratory work has been a topic of much discussion and investigation since the l a t t e r part of the nineteenth century when individual laboratory work by the student became common. The following survey w i l l not attempt to provide a review of investigations that concern themselves with arguments for the inclusion of or elimination of laboratory work in science c u r r i c u l a . Instead what w i l l be under review is the use of the laboratory in science education and the perceived effectiveness of various forms of laboratory i n s t r u c t i o n . The f i r s t part of this survey w i l l look at the variety of studies that have examined the so-called ' t r a d i t i o n a l ' laboratory method as outlined in many science laboratory manuals and i t s effectiveness in providing the student with what the authors of the manuals perceive to be valuable laboratory experience. Following this w i l l be an examination of studies that make comparisons between the t r a d i t i o n a l laboratory method and alternative forms of laboratory i n s t r u c t i o n . The d e f i n i t i o n of ' t r a d i t i o n a l ' laboratory instruction as used in this review and as used by researchers is as follows. The general feature of these t r a d i t i o n a l laboratory - 8 -experiments is that everything about the laboratory experiment is explained to the students before they proceed. They are given the theory underlying the experiment, the exact experimental procedure to be used and a detailed description of how the data are to be analyzed. An i l l u s t r a t i o n of what the data should look l i k e is often given. The main purpose of such an approach is to allow the students to v e r i f y that the experiment as presented does work. Education researchers often use such terms as " v e r i f i c a t i o n " laboratories or "conventional" laboratories when referri n g to t r a d i t i o n a l laboratory i n s t r u c t i o n . Science educators have decried such emphasis on v e r i f i c a t i o n in the science laboratory. Rasmussen (1970), in an a r t i c l e in Bioscience c r i t i c i z e d both college science teachers and teacher educators. He claimed that high school laboratory work is no better than i t is because formal science school training is "... more often ... about science rather than in science..." (p.292), with very limited opportunities to r e a l l y investigate ideas. Laboratory a c t i v i t i e s , according to Rasmussen, are largely i l l u s t r a t i v e , non-investigative, and not p a r t i c u l a r l y e x c i t i n g . Laboratory achievement is usually evaluated separately from the science content of the course. "Operationally, the student learns that the function of the laboratory should be c e r t i f i c a t i o n of statements made by the teacher or by the textbook ..." (p.292). Rasmussen said that, in good science teaching, "the textbook supports the laboratory but in most present cases these roles are - 9 -r e v e r s e d . " He p o i n t e d out t h a t the B i o l o g i c a l S c i e n c e s C u r r i c u l u m Study (B.S.C.S.) m a t e r i a l s are not as s u c c e s s f u l as one might w i s h "... due i n l a r g e p a r t to t e a c h e r r e l u c t a n c e t o change t h e i r mode of o p e r a t i o n " (p.293). In r e v i e w i n g p r e v a i l i n g l a b o r a t o r y p r a c t i c e s , Lee N e d e l s k y (1965) compared the c o n v e n t i o n a l or t r a d i t i o n a l l a b o r a t o r y i n s t r u c t i o n as a k i t c h e n where s t u d e n t s f o l l o w a r e c i p e ; t h a t i s , the s t u d e n t i s t o l d p r e c i s e l y how to s e t up the a p p a r a t u s , what r e a d i n g s to t a k e , and what e q u a t i o n s t o a p p l y t o the d a t a . N e d e l s k y f e l t t h a t t h i s r e p r e s e n t e d a " s t e r i l e o r d e r l i n e s s " where the i n s t r u c t o r c a r e f u l l y watched the s t u d e n t s to be sure they wasted no time nor g a t h e r e d any unnecessary d a t a . C o n c l u s i o n s f o r the experiment were w r i t t e n o u t s i d e the l a b o r a t o r y p e r i o d , away from the e x p e r i m e n t a l s e t - u p and phenomena o b s e r v e d . By comparison N e d e l s k y d e s c r i b e s the i n v e s t i g a t i v e l a b o r a t o r y as; l e a v i n g the s t u d e n t to h i s own d e v i c e s to f i n d o u t a l l he or she c o u l d about a phenomenon. In t h i s l e s s s t r u c t u r e d l a b o r a t o r y the s t u d e n t has more time to t h i n k and t o e x e r c i s e i n g e n u i t y , and i s more m o t i v a t e d . T h i s type of l a b o r a t o r y , however, c o s t s more and i s c h a r a c t e r i s e d by few c l e a r l y d e f i n e d b e h a v i o u r a l o b j e c t i v e s . The i n s t r u c t o r needs t o be an e x p e r t i n g u i d i n g the s t u d e n t toward the major o b j e c t i v e s of the c o u r s e . N e d e l s k y found t h a t the h i g h e r c o s t of equipment and the h i g h e r c o s t of t e a c h i n g p e r s o n n e l was the main reason f o r the c o m p a r a t i v e r a r i t y of the u n s t r u c t u r e d l a b o r a t o r y . However, Ne d e l s k y found t h a t most t e a c h e r s - 10 -f a m i l i a r with the u n s t r u c t u r e d l a b o r a t o r y expressed that i t s advantages outweighed i t s disadvantages. A recent a r t i c l e c r i t i c i s i n g the c o l l e g e s c i e n c e l a b o r a t o r y was p u b l i s h e d i n The C h r o n i c l e of Higher Education (1980). P i c k e r i n g i d e n t i f i e d two misconceptions about the use of the l a b o r a t o r y i n c o l l e g e s c i e n c e . Misconception one was t h a t l a b o r a t o r i e s should somehow " i l l u s t r a t e " l e c t u r e courses. This f u n c t i o n i s not p o s s i b l e i n a simple, one-afternoon e x e r c i s e , P i c k e r i n g s a i d , because "most s c i e n t i f i c theory i s based on a l a r g e number of very s o p h i s t i c a t e d s u p p o r t i n g experiments" (p. 80). Misconception two i s that l a b o r a t o r i e s e x i s t to teach " f i n g e r s k i l l s " . P i c k e r i n g claimed that very few of the techniques students l e a r n i n t h e i r s c i e n c e l a b o r a t o r i e s w i l l be d i r e c t l y usable i n the c a r e e r s they p l a n . Many of the s k i l l s students l e a r n i n the l a b o r a t o r i e s are o b s o l e t e . Few b i o l o g i s t s do d i s s e c t i o n s and few chemists do t i t r a t i o n s . Such s k i l l s are worth teaching o n l y as t o o l s to be mastered f o r b a s i c s c i e n t i f i c i n q u i r y and as ends i n themselves (p. 80) . P i c k e r i n g d i s t i n g u i s h e d between l e c t u r e and l a b o r a t o r y courses by contending that a good l a b o r a t o r y course should be an e x e r c i s e i n doing s c i e n c e while a good l e c t u r e course has the o b j e c t i v e of teaching about s c i e n c e . He viewed good l a b o r a t o r y teaching as being e s s e n t i a l l y S o c r a t i c , i n v o l v i n g the posing of c a r e f u l l y d e f i n e d questions to be asked of nature. The i n t e l l e c t u a l processes students should use are - 11 -those of s c i e n t i f i c research so they come to see how d i f f i c u l t i t is to obtain meaningful data. Such a laboratory course could e a s i l y be defended as f i t t i n g into a l i b e r a l education, according to Pickering. Unfortunately most laboratory courses do not f i t into this model. Pickering sees other d i f f i c u l t i e s as well. Too few lab. courses off e r any sort of confrontation with the unknown... The element of creative surprise is almost completely missing. The results of an experiment should be ambiguous enough so that a student is compelled to think through the bearing of his results on the possible conclusion (p.80). Marshall D. Herron (1971) examined 41 Chem. Study laboratory exercises for their content and stated purposes. He grouped these 41 exercises into three major categories: (1) exercises through which the student was expected to "discover" certain specified p r i n c i p l e s or r e g u l a r i t i e s in chemical phenomena; (2) exercises involving inference or problem-solving behaviour and having no pre-determined, unique solution; and (3) exercises said to " i l l u s t r a t e " or to "give the student the chance to observe, together with exercises intended to give the student practice in developing laboratory techniques" (p.196). - 12 -A c c o r d i n g t o H e r r o n , 24 of the 41 l a b o r a t o r y e x e r c i s e s (more than 50%) were of the i l l u s t r a t i v e - d e m o n s t r a t i v e v a r i e t y . S i x were of the open-ended p r o b l e m - s o l v i n g t y p e , w i t h f o u r of the s i x o c c u r r i n g v e r y l a t e i n the c o u r s e . He c o n c l u d e d , " I n the l i g h t of t h i s a n a l y s i s , i t would appear t h a t the ' d i s c o v e r y 1 r u b r i c i s m i s l e a d i n g as a p p l i e d to the l a b o r a t o r y p o r t i o n of these m a t e r i a l s " (p.198). H e r r o n , q u o t i n g from BSCS m a t e r i a l s , i d e n t i f i e s the g o a l of the t e x t of the cour s e as t h a t of h e l p i n g the s t u d e n t " o b t a i n some u n d e r s t a n d i n g o f the n a t u r e o f s c i e n c e as a v i g o r o u s i n t e r a c t i o n of f a c t s and i d e a s " (p.201). However, Herron m a i n t a i n s t h a t l a b o r a t o r y work i n the BSCS c o u r s e l a c k s emphasis on the o r i g i n of s c i e n t i f i c problems. L u n e t t a and Tamir (1978) u s i n g an i n s t r u m e n t c a l l e d the L a b o r a t o r y S t r u c t u r e and Task A n a l y s i s I n v e n t o r y ( L A I ) , examined l a b o r a t o r y a c t i v i t i e s from P r o j e c t P h y s i c s and the P h y s i c a l S c i e n c e Study Committee (PSSC) m a t e r i a l s , to check on Herron's c o n t e n t i o n t h a t the m a t e r i a l s d i d not always l e n d themselves to the g o a l s the p r o j e c t d e v e l o p e r s a d v o c a t e d . They d e c i d e d t h a t the l a b o r a t o r y g u i d e s f o r the two co u r s e s were l a c k i n g i n i n s t r u c t i o n s and q u e s t i o n s t h a t might s t i m u l a t e such i n q u i r y a c t i v i t i e s as the f o r m u l a t i o n of hy p o t h e s e s , the d e f i n i t i o n of problems, and the d e s i g n o f e x p e r i m e n t s . They i d e n t i f i e d what they c o n s i d e r e d to be s i x i m p o r t a n t d e f i c i e n c i e s where s t u d e n t i n v o l v e m e n t , o r i t s l a c k were - 13 -concerned: (1) no student involvement in identifying and formulating problems or in formulating hypotheses, (2) r e l a t i v e l y few opportunities to design observation and measurement procedures, (3) even fewer opportunities to design experiments and to work according to their own design, (4) lack of encouragement to discuss limitations and assumptions underlying the experiments, (5) lack of encouragement to share student e f f o r t s in laboratory a c t i v i t i e s when this is appropriate, and (6) lack of e x p l i c i t provisions for post-laboratory discussions to f a c i l i t a t e consolidation of findings and understanding (p.10). As indicated, s c i e n t i s t s and science educators decry the use of cookbook-type, and v e r i f i c a t i o n laboratories and advocate laboratory a c t i v i t i e s that are designed to convey to pupils the nature of science, i t s methods, and the s p i r i t of inquiry. 2.1 Alternative Forms of Laboratory Instruction as Compared to More T r a d i t i o n a l Forms In reviewing the empirical studies, i t becomes apparent that many researchers have examined forms of laboratory instruction that d i f f e r from t r a d i t i o n a l methods of ins t r u c t i o n . Many of these studies have arisen perhaps from f r u s t r a t i o n with t r a d i t i o n a l laboratory practices. Indeed, such f r u s t r a t i o n may have spawned new and innovative methods that the researchers wish to test empirically as to their - I n -effectiveness in the cognitive, aff e c t i v e and psychomotor domains. The studies presented here w i l l be grouped according to the dependent variable(s) they measure. The following variables w i l l be considered: academic achievement, student interest, cognitive a b i l i t y , psychomotor s k i l l s , and student understanding of the nature and process of science. 2.1.1. Academic Achievement Using a multivariate analysis of variance and trend analysis of adjusted means over ten quizzes, Egelston (1973) found that by using an 'inductive' method of laboratory instruction in comparison to the t r a d i t i o n a l method, superiority of achievement was obtained by the group involved with the inductive procedures. Interestingly, over the span of the ten exercises, each followed by a quizz, the achievement of the experimental group using the inductive method, started out at a lower le v e l but eventually surpassed that of the control group which used the t r a d i t i o n a l method. Egelston attributes this early poor performance to the novelty of the inductive method which hindered achievement i n i t i a l l y . Egelston's inductive method which she defines as an open-ended approach where the student develops and researches their own problem, is similar to that of James Bock's (1979) alternate laboratory method which he c a l l s an "inquiry-investigative" program. Unlike Egelston, however, Bock found - 15 -no s i g n i f i c a n t differences between the academic achievement of those students who undertook the t r a d i t i o n a l laboratory exercises as depicted in standard Biology texts and those who pursued the inquiry-investigative program. Tanner (1969) also found no s i g n i f i c a n t differences in measure of comprehension, l a t e r a l transfer and retention when comparisons were made of students engaged in an inductive or discovery method vs the t r a d i t i o n a l method which Tanner c a l l s the "didactic" method. Indeed, of the various studies that measured academic achievement after an exposure to an alternate laboratory method few studies indicated a strong trend toward increased retention and comprehension of knowledge. 2.1.2 Student Interest Using an inquiry type of laboratory approach, Moll and Allen (1982) were interested in whether students would exhibit a better attitude towards their laboratory work. Using an analysis of variance of their data some s i g n i f i c a n t differences were obtained in the positive d i r e c t i o n . At least within the parameters of their study, Moll and Allen did find that students were more receptive to laboratory work which allows for more independent choice of problem, planning and conducting of experiment. In contrast, Robert A l l i s o n ' s (1972) study did not show the marked improvement in students' positive attitude - 16 -towards laboratory work that Moll and Allen showed. A l l i s o n ' s study compared inquiry laboratory experience to conventional laboratory in a college chemistry course. He compared how the two methods effected changes in student attitudes towards science, c r i t i c a l thinking, laboratory s k i l l s and self-evaluation. He concludes that the inquiry approach is neither more nor less e f f e c t i v e that in the conventional approach in improving attitudes toward science, c r i t i c a l thinking or laboratory s k i l l s . A comparison of an auto-tutorial laboratory and students in a less independent laboratory in physical science was conducted by Harold Park and John Butzow (1975). Using examinations on independence of work-study habits and attitude toward the course, they found that independent study students achieved higher scores on independence of study, but found no s i g n i f i c a n t difference in attitudes. Studies on student attitude either indicate that attitude improves when students work with an inquiry laboratory format, or that attitude remains the same as that found in students working with a conventional format. 2.1.3 C r i t i c a l Thinking and Reasoning A b i l i t y A number of studies measured the cognitive a b i l i t i e s of students engaged in alternative laboratory a c t i v i t i e s . P a r t i c u l a r among the cognitive measures were those of c r i t i c a l thinking and reasoning. - 17 -Unlike the categories of academic achievement and student i n t e r e s t , c r i t i c a l thinking and reasoning i s , by indication of most studies, enhanced s i g n i f i c a n t l y by exposure of students to laboratory methods which d i f f e r from the t r a d i t i o n a l . Pavelich and Abraham (1979) developed what they called a "guided-inquiry" format for freshman chemistry students. Similar to other methods previously discussed, the guided-inquiry format allows the student considerable freedom to investigate a problem of their choice, design an experiment and analyse the r e s u l t s . Using a Piagetian-type paper and pencil test developed by the Cognitive Analysis Project, Pavelich and Abraham were able to show that an exposure to an inquiry laboratory format allows the student to ... investigate chemistry at a level con-sis t e n t with his/her l e v e l of i n t e l l e c t u a l development ... the more concrete student experiences chemistry solely at the concrete l e v e l ; whereas the formal student has experiences which tax his/her abstract thinking a b i l i t i e s (p.103). Rickert (1962) studied the development of the c r i t i c a l thinking a b i l i t y of college freshmen and i t s relationship to the organisation of a physical science laboratory course. An experimental course, in which the students were given opportunities to analyse problems, c o l l e c t and organise data, test hypotheses, and to draw conclusions from data, was introduced. This experimental group of students was compared with a control group which followed a t r a d i t i o n a l survey laboratory course format. A s i g n i f i c a n t difference between - 18 -the groups' c r i t i c a l thinking a b i l i t y , and the ACE Test of C r i t i c a l Thinking, was found which favoured the experimental group. Rickert concluded that a physical science laboratory course can improve students' a b i l i t y to think c r i t i c a l l y i f the laboratory course provides them with opportunities to use c r i t i c a l thinking and problem solving methods. Tamir and Glassman (1971) compared BSCS and non-BSCS students' performance on an inquiry-oriented performance laboratory t e s t . They found that the BSCS students did s i g n i f i c a n t l y better, due mainly to superiority in reasoning and s e l f r eliance. The researchers concluded that BSCS students had a d i s t i n c t advantage in solving open-ended problems using experimental procedures in the laboratory. Similar results were obtained two years e a r l i e r by Edgar (1969) . Campbell (1978) evaluated a Piagetian-based model for developing materials and instructing the laboratory portion of a beginning college physics course. Students (N=55) in two di f f e r e n t states were involved. Although there were no s i g n i f i c a n t improvements in learning physics content, there was a s i g n i f i c a n t difference in the use of more f o r m a l i s t i c reasoning a b i l i t i e s for the students. Campbell's "learning cycle" model involved three separate but interrelated a c t i v i t i e s : exploration, concept invention, and concept application with 10 "laboratory intervention periods". The above studies do provide some support for the idea that - 19 -laboratory a c t i v i t i e s that d i f f e r from the t r a d i t i o n a l v e r i f i c a t i o n - t y p e can be used to help students learn to think c r i t i c a l l y . 2.1.4 Understanding the Nature and Processes of Science  The majority of researchers who measured students' understanding of science and science processes used a discovery or inquiry laboratory approach as their experimental method. Researchers allowed students a f a i r degree of freedom in selecting a problem and in analysing their own research. In this way they believed that a student would gain a greater understanding of the science process as the students would be d i r e c t l y exposed to the frustrations and d i f f i c u l t i e s in developing his/her own experimental design. Raghubir (1979) compared a "laboratory- investigative" approach to the t r a d i t i o n a l laboratory approach and found that the investigative approach provided students with the opportunity to develop the strategies and attitudes associated with s c i e n t i f i c investigation. Raghubir concludes his study by stating emphatically that, "... conventionally taught science courses are, t y p i c a l l y , instructor-centred, in the sense that they provide the student with very l i t t l e opportunity for s e l f - i n i t i a t e d and sel f - d i r e c t e d study" (p. 16). S i m i l a r l y , Boohar (1975) developed a laboratory program that allowed for student-directed a c t i v i t i e s . Boohar found that i n i t i a l l y students were frustrated by the lack of - 20 -d i r e c t i o n but that ultimately, having completed an inquiry-based a c t i v i t y , the students f e l t that they had an understanding of the processes of science. Boohar, unfortunately did not conduct an empirical study using any instrument described in the related l i t e r a t u r e . Instead, his conclusions are based on subjective findings and random verbalizations by students. Stekel's (1970) work supports the findings of Raghubir (1979) and Boohar (1975). Stekel compared the effectiveness of two d i f f e r e n t laboratory programs in college physical science: a t r a d i t i o n a l program with a laboratory manual and a more f l e x i b l e , open-ended program. In the open-ended approach students selected their own problems related to a general topic, designed their own procedures, and completed an experiment. Stekel found a s i g n i f i c a n t difference (p <.01), favouring the open-ended group, on the understanding of actions and operations of s c i e n t i s t s . S e r l i n (1977) also talked about a discovery laboratory in college physics. In his terms, such a laboratory would emphasize hypothesizing, experimenting, and inf e r r i n g rather than fact-gathering and p r i n c i p l e v e r i f i c a t i o n . S e r l i n established three c r i t e r i a for the discovery laboratory: (a) a c t i v i t i e s be matched to the developmental stage of the learner, (b) guidance be provided by the use of advance organisers, and (c) further guidance be provided by describing the nature of science as a discovery a c t i v i t y for the students. Two experimental groups and one control group were - 21 -involved. Students were provided practice in the process of science problem solving, and in setting up and providing standards of evaluation. With verbal SAT scores used as a covariate, S e r l i n found that the discovery laboratory was e f f e c t i v e in increasing students' science process s k i l l s (p = 0.05) . A few studies indicated no s i g n i f i c a n t difference between t r a d i t i o n a l and alternative laboratory forms on measures of student understanding of the nature and process of science. For example, Cannon (1975) in a study that is very similar to Stekel's (1970), used the Welch Process of Science Inventory to measure student understanding of the process of science. Unlike Stekel (who used the same instrument), Cannon found there was no difference between laboratory groups with respect to understanding the process of science. In summary there are contrasting opinions as to whether student understanding of the nature and process of science can be enhanced by allowing that student a degree of freedom in d i r e c t i n g their own work. Yet, of the nine studies found in the recent l i t e r a t u r e , seven indicated that the alternative laboratory method was superior when contrasted with the t r a d i t i o n a l method. 2.2 Measurement of Laboratory Research Study Outcomes No matter what the desired outcomes of laboratory instruction are, increased achievement, more favourable attitude toward science, increase in c r i t i c a l thinking s k i l l s - 22 -or increase in the understanding of the nature and process of science, measures must be taken to v e r i f y whether the outcomes have been achieved. Outcomes of laboratory instruction in science have been measured with paper and pencil tests, with laboratory s k i l l examinations, with the use of checklists and rating scales, with classroom observational instruments focussing on verbal or non-verbal interaction, or some combination of these. If the goals are to be achieved the researcher needs to make certain that the measure used is s u f f i c i e n t l y sensitive to detect any changes that occur between the beginning and end of the treatment. In many studies, investigator-designed tests or other instruments are used. Frequently information about r e l i a b i l i t y and v a l i d i t y , as well as the methods used to obtain these measures, is sketchy. Even more frequently an explanation of the theoreti c a l rationale underlying the instrument is not presented. These types of information are seldom found in the abstract of a doctoral d i s s e r t a t i o n ; and frequently are not provided in journal a r t i c l e s based on the di s s e r t a t i o n research. Welch (1971) noted that 30 research reports concerning i n s t r u c t i o n a l procedures (including laboratory instruction) made no connection between the in s t r u c t i o n a l procedure and the test chosen to measure the e f f e c t . This is important when considering Tamir's (1972) statement that the laboratory in - 23 -science education is not only a unique mode of instruction but also a unique mode of assessment. Therefore i t is desirable to develop sensitive evaluation instruments that w i l l provide information about what the student does in the laboratory and about his/her growth and a b i l i t y to develop inquiry and other related laboratory s k i l l s . The effects of science laboratory experiences on achievement have normally been measured by the use of an investigator-designed test or by the use of a well-known test such as the Nelson Biology test, to ci t e only one example. Science teaching t r a d i t i o n a l l y has emphasized the learning of s c i e n t i f i c 'information', concepts, p r i n c i p l e s , and fac t s , with l i t t l e emphasis on the development of problem-solving s k i l l s , and this orientation is reflected in many of the test instruments that were used. Tests often emphasized student a b i l i t y to id e n t i f y or r e c a l l facts at r e l a t i v e l y low taxonomic levels but seldom have assessed development of higher l e v e l s k i l l s that involve application, analysis, synthesis and evaluation (Bloom, 1956). 2.2.1 Watson-Glaser C r i t i c a l Thinking Appraisal (WGTCA)  According to information in the Mental Measurements Yearbook (1959), the sub-tests of this instrument are designed to evaluate the a b i l i t y to interpret data, to draw correct inferences, to draw appropriate deductions, to recognise assumptions, and to evaluate arguments. Such mental operations can be accomplished in many context areas that are not unique to science. Indeed, the WGCTA (Watson & Glaser, 1961) has l i t t l e to do with science teaching in general or with laboratory work in p a r t i c u l a r . The instrument was constructed and validated for use in the so c i a l sciences and is concerned with s o c i a l and h i s t o r i c a l phenomena. While one can argue that transfer of learning is a desirable outcome of ins t r u c t i o n , the difference between science laboratory experience and h i s t o r i c a l and s o c i a l events is very large. Seven investigators used the WGCTA test in their research related to the science laboratory. Three (Hoff, 1970; Rogers, 1972; Sorensen, 1966) reported that students involved in their treatment groups (an alternative laboratory approach) made s i g n i f i c a n t gains in their c r i t i c a l thinking scores over and above those involved in the control groups who pursued a t r a d i t i o n a l laboratory approach. Four ( A l l i s o n , 1973; Dawson, 1975; M i t c h e l l , 1978; Sherman, 1969) reported no s i g n i f i c a n t difference between the alternative laboratory groups and the t r a d i t i o n a l group on measure of reasoning a b i l i t y . 2.2.2 Test on Understanding Science A second, frequently used, instrument is the Test on Understanding Science (TOUS), developed by Cooley and Klopfer (1963). Form W of TOUS is a four-alternative sixty item multiple choice test. The items are categorized into three subscales: - 25 -Subscale I. Understanding about the s c i e n t i f i c enterprise (18 items) Subscale I I . The s c i e n t i s t (18 items) Subscale I I I . Methods and aims of science (24 items) The TOUS was developed as a research t o o l . Its content v a l i d a t i o n rests upon an analysis of s c i e n t i s t s at work and upon a diverse l i t e r a t u r e including the history and philosophy of science. Cri t i c i s m s of TOUS have emerged. Welch (1969) has suggested that form W might be improved through revision and stronger v a l i d i t y evidence. Wheeler (1968) has been more s p e c i f i c . He states that too many items embrace a negative viewpoint of science. Aikenhead (1973) suggests that some items evoke a response of attitude; i . e . , students perceive the test as concerning their appreciation or lack of appreciation for science and s c i e n t i s t s . Some items, Aikenhead reports, are answered according to a s c i e n t i s t s ' 'good guy' image. In the four d i s s e r t a t i o n studies in which use of TOUS was reported, three researchers (Baxter, 1969; Sherman, 1969; Smith, 1971) reported no s i g n i f i c a n t difference between groups involved in alternative laboratory work and those in the t r a d i t i o n a l groups. The fourth reported that the students in the experimental group (a revised general education laboratory course in physical science) exhibited s i g n i f i c a n t gains in TOUS scores, even when differences in a b i l i t y , scholastic achievement, background knowledge, or s k i l l were covaried out - 26 -of the analysis, and concluded that the laboratory exercises had made an important contribution to student knowledge as tested by the TOUS instrument (Whitten, 1971). 2.2.3 Welch Science Process Inventory (SPI) Wayne Welch and Milton 0. Pe l l a (1968) developed a v a l i d , r e l i a b l e and useable instrument to inventory the knowledge of the process of science. This instrument consists of 135 items pertaining to assumptions, a c t i v i t i e s , products and ethics of science. V a l i d i t y was established by determining the instrument discriminating power between students, science teachers, and s c i e n t i s t s . R e l i a b i l i t y was measured by Kuder-Richardson formula 20. The authors concluded that the test measures the understanding of the process of science by high school students, their teachers, as well as professional s c i e n t i s t s . Douglas Magnus (1973) and Edward Lucy (1972) conducted experiments comparing the s e l f - d i r e c t e d laboratory studies to the conventional laboratory. In both cases the SPI instrument was used to measure the understanding of the process of science. Lucy found a s i g n i f i c a n t improvement in the independent laboratory students' understanding of the process of science. The Magnus study revealed no difference between the experimental and control groups in the understanding of the process of science. Judith Damewood (1971) evaluated student competence in the process of science in a physical science course for - 27 -prospective elementary teachers. It was found that students who were free to choose their own laboratory exercise performed at a higher l e v e l on the SPI than the student using the prescribed, content-based laboratory exercises. In a similar study, but with students of physics, Spears and Zollman (1977) focussed on the use of laboratories intended to provide students with experiences that would aid in understanding the process of science as well as the content of science. Students were placed in either a structured, t r a d i t i o n a l laboratory situation or in an unstructured, open-ended one. The SPI instrument was given both as a pre-test during the f i r s t week of the semester, and as a post-test, during the l a s t week. Pre-test scores, laboratory grade, and lecture instructor were used as covariates in the data analysis. When scores were analysed, no differences were found for the components of the SPI: assumptions, nature of outcome, ethics and goals. S i g n i f i c a n t differences did occur in the fourth component, a c t i v i t i e s , with students in the structured laboratory scoring higher in this area. Spears and Zollman conclude by stating that, "Unstructured laboratories can provide useful experience for students having p r i o r experience in s c i e n t i f i c experimentation ... and training in the s c i e n t i f i c process..." (p.37). F i n a l l y , of the four d i s s e r t a t i o n studies in which use of the SPI instrument was reported, two (Cannon, 1975; Dawson, 1975) reported findings of no s i g n i f i c a n t difference and two (Smith, 1972; Stekel, 1970) reported s t a t i s t i c a l l y s i g n i f i c a n t - 28 -increases in the understanding of the process of science by the alternate laboratory group over the t r a d i t i o n a l laboratory group. 2.3 Summary The review of l i t e r a t u r e indicates many studies dealing with comparisons between the t r a d i t i o n a l laboratory method and some alternative laboratory method. In the main, the t r a d i t i o n a l method may be described as involving students in v e r i f i c a t i o n laboratories that are quite structured, allowing students l i t t l e opportunity to explore for themselves the complexities of the s c i e n t i f i c process. The alternative laboratory methods examined in this review come under a variety of names given them by their researchers - 'inquiry-based' exercises, 'open-ended' laboratories, 'investigative' procedures, 'inductive' exercises, and the 'discovery' approach. A l l of these methods tend to emphasize student involvement in problem-creation, hypothesizing, experimental design and in f e r r i n g rather than fact-gathering and p r i n c i p l e v e r i f i c a t i o n . As a means of encapsulating the variety of studies examined in this review, four tables have been compiled which reveal the essential c h a r a c t e r i s t i c s of the studies. Each table is categorized according to the dependent variable measured by researchers. These tables indicate that in a l l of the studies surveyed (except that done by Spears and Zollman (1977)) the - 29 -a l t e r n a t i v e l a b o r a t o r y method was found to be e i t h e r s u p e r i o r t o o r the same as the t r a d i t i o n a l method of l a b o r a t o r y p r o c e d u r e on the v a r i o u s measures examined by the r e s e a r c h e r s . However the number of s t u d i e s t h a t showed no s i g n i f i c a n t d i f f e r e n c e between the methods c o u p l e d w i t h the r e s e a r c h e r use o f i n a p p r o p r i a t e i n s t r u m e n t s to measure v a r i a b l e s , i n d i c a t e the need f o r f u r t h e r r e s e a r c h . TABLE 1 - SUMMARY OF STUDIES COMPARING THE TRADITIONAL LABORATORY METHOD TO AN ALTERNATE LABORATORY METHOD ON MEASURES OF ACADEMIC ACHIEVEMENT Researcher Alternate Laboratory Instrument Results Type __ Used  No Si g n i f i c a n t S i g n i f i c a n t S i g n i f i c a n t Gain in Gain in Difference Scores on Scores on Alternate T r a d i t i o n a l Lab. Type Lab. Type Egelston Inductive Researcher-Constructed Tests O Bock Inquiry-Investigative Knowledge and Application Subtests from BSCS Tanner Inductive Researcher-Constructed Test Pare & Independent study Nelson Biology Test x TABLE 2 - SUMMARY OF STUDIES COMPARING THE TRADITIONAL LABORATORY METHOD TO AN ALTERNATE LABORATORY METHOD ON MEASURES OF ENHANCED STUDENT INTEREST IN LABORATORY COURSE OF STUDY Researcher A l t e r n a t e Laboratory Type Instrument Used Re s u l t s No S i g n i f i c a n t S i g n i f i c a n t S i g n i f i c a n t Gain i n Gain i n D i f f e r e n c e Scores on Scores on A l t e r n a t e T r a d i t i o n a l Lab. Type Lab. Type Moll and A l l e n Inquiry Researcher Constructed Test A l l i s o n Inquiry Researcher Designed Questionnaire Pare and Butzow Independent Study Student V e r b a l i z a t i o n s TABLE 3 - SUMMARY OF STUDIES COMPARING THE TRADITIONAL LABORATORY METHOD TO AN ALTERNATE LABORATORY METHOD ON MEASURES OF CRITICAL THINKING AND REASONING ABILITIES Researcher A l l i s o n Pavelich and Abraham Rickert Tamir and Glassman Campbell Hoff Rogers Sorensen Dawson Mitchell Sherman Alternate Laboratory Type  Inquiry G Inquiry Inquiry BSCS vs non-BSCS 'Learning-Cycle 1 Model Inquiry Discovery Open-ended Discovery Discovery Inquiry Instrument Used Results No Si g n i f i c a n t S i g n i f i c a n t S i g n i f i c a n t Gain in Gain in Difference Scores on Scores on Alternate Tr a d i t i o n a l Lab . Type Lab . Type WGCTA Piagetian-Type Paper and Pencil Test ACE Test of C r i t i c a l Thinking BSCS Inquiry Test Researcher-Constructed Test WGCTA WGCTA WGCTA WGCTA WGCTA WGCTA x x X TABLE 4 - SUMMARY OF STUDIES COMPARING THE TRADITIONAL LABORATORY METHOD TO AN ALTERNATE LABORATORY METHOD ON MEASURE OF STUDENT UNDERSTANDING OF THE NATURE AND PROCESS OF SCIENCE Researcher Raghubir Boohar Stekel S e r l i n Cannon Dawson Baxter Sherman Alternate Laboratory TYpe Instrument Used Investigative Student-Directed Open-ended Discovery Discovery Discovery Investigative Student-Directed Subjective Student Responses Subjective Student Responses SPI Subjective Student Responses SPI Subjective Student Responses TOUS TOUS Results No S i g n i f i c a n t S i g n i f i c a n t S i g n i f i c a n t Gain in Gain in Difference Scores on Scores on Alternate T r a d i t i o n a l Lab. Type Lab. Type x x x x x X Smith Investigative TOUS TABLE 4 - SUMMARY OF STUDIES COMPARING THE TRADITIONAL LABORATORY METHOD TO AN ALTERNATE LABORATORY METHOD ON MEASURE OF STUDENT UNDERSTANDING Continued OF THE NATURE AND PROCESS OF SCIENCE Researcher Alternate Laboratory Instrument Results Type Used  No Sig n i f i c a n t S i g n i f i c a n t S i g n i f i c a n t Gain in Gain i n Difference Scores on Scores on Alternate T r a d i t i o n a l Lab. Type Lab. Type Whitten Magnus Lucy Damewood Spears and Zollman Smith Researcher-Revised Lab. Course Self-Directed Self-Directed Self-Directed Open-ended Discovery TOUS SPI SPI SPI SPI SPI x (4th comp. only) - 35 -CHAPTER 3 METHOD OF STUDY 3.0 INTRODUCTION A nonequivalent control group design (Campbell and Stanley, 1963, pp. 47-50) was used to test the hypothesis of no difference between the means of the t r a d i t i o n a l laboratory method and the investigative-based laboratory method on the dependent variable considered. In what follows, the components of this design, including description of the subjects, selection of the subjects, teaching methods, design of the study, instrumentation, data presentation and analyses are described. 3.1 Population 3.1.1 Description The subjects in this study were grade 12 students enrolled in Biology twelve at a Senior Secondary School, in D i s t r i c t #38, Richmond during the 1982-83 school season. The Senior Secondary School enrolls students in two grades, 11 and 12 and at the time of this study there were approximately 1,000 students enrolled. The school is located in the geographical centre of Richmond and the students come from middle class or lower middle class families. Students of the Biology 12 course are generally considered "academic" in that a majority of the students have - 36 -aspirations to continue their education at a post-secondary l e v e l . 3.1.2 Selection of the Subjects Two classes of Biology 12, taught by the author, took part in this study. One class, consisting of 21 subjects, were from the author's block B class and the other class, block C, consisted of 20 students. Block B became the control group as these students were exposed to the t r a d i t i o n a l method of laboratory procedures from laboratory texts issued for the course. Block C students were the experimental group that were required to be exposed to the author's investigative-based laboratory method. Although a r e l a t i v e l y small number of subjects took part in this study, the minimum requirement of 30 individuals l a i d down by Borg and Gall (1979, p.195) was exceeded. Campbell and Stanley (1963) point out that the use of naturally formed classes in experiments is an acceptable procedure in the s o c i a l sciences when random assignment of subjects to treatment is not possible. Such is the case in this study where students were allocated to s p e c i f i c blocks in a non-random fashion. One could not assume randomness as certain students were assigned to s p e c i f i c blocks by school counsellors in accordance with the students' p a r t i c u l a r program requests. - 37 -The c h a r a c t e r i s t i c s of the two Biology 12 classes are outlined below: TABLE 5 CHARACTERISTICS OF CLASSES Class Size Male Female Block B (control) 21 7 14 Block C 20 8 12 The author who participated as the teacher for both classes had taught senior high school biology for six years pr i o r to the study. Prior to t h i s , he taught science in a junior high school for two years. The author, at the time of this study, was 30 years of age. - 38 -3.2 Research Design The research design used in this study was the nonequivalent control-group design (Campbell and Stanley, 1963, pp. 47-50) where an experimental and control group are both given a pretest and posttest, but in which the groups do not have pre-experimental equivalence. The design is represented by the following diagram: _ 0 _ X _ 0 _ 0 0 where 0 represents pretest or posttest measurement of the dependent variable, understanding of the process of science; and X represents the experimental treatment. As a result of the fact that students were assigned by school counsellors to either the control or experimental groups, i t may not be assumed that experimental subjects were randomly selected. Thus, this research design is quasi-experimental as opposed to true-experimental. The main d i f f i c u l t y with non-random assignment is that the experimental and control groups may d i f f e r in some c h a r a c t e r i s t i c , thus confounding the interpretation of the experiment. To lessen these i n i t i a l differences between treatment groups, with respect to prior achievement, an analysis of covariance (ANCOVA) was used as a s t a t i s t i c a l technique. In the nonequivalent control-group design, there is some threat to internal v a l i d i t y a r i s i n g from interaction between such variables as selection and maturation, selection and history, or selection and testing. In the absence of - 39 -randomization, the p o s s i b i l i t y always exists that some c r i t i c a l difference, not reflected in the pretest, is operating to contaminate the posttest data. An analysis of covariance mathematically considers some of these p o s s i b i l i t i e s and w i l l indicate the importance of such interactions. The nonequivalent control group design has some p r a c t i c a l advantages over the true experimental control-group design. This is due, in part, to the fact that the former design deals with intact classes and does not disrupt the school's program. 3.3 Evaluation Instrument The Welch Science Process Inventory (SPI) was used in this study to determine i f there were changes in the students' understanding of the process of science. This instrument was developed by Wayne W. Welch (1968) and is available from the author for research purposes only. The test consists of 135 statements concerning a c t i v i t i e s , assumptions, products and ethics of science. The student was asked to agree or disagree with each of the statements. The response of the students was scored using a key designed for the instrument. The r e l i a b i l i t y of Form D, as measured by the Kuder-Richardson Formula 20, i s 0.86 based on a sample of 171 students (mean score and standard deviation of 103.78 and 13.10 respectively). These students were drawn randomly from - 40 -a population of 2,500 senior high school students in 50 d i f f e r e n t high schools throughout the United States. The test's r e l i a b i l i t y was measured with respect to senior high students and i t has been successfully used with undergraduate college students (Magnus, 1973) and by the test's author on college graduates (Welch and Walberg, 1968). Content v a l i d i t y was established by 14 research s c i e n t i s t s agreeing to the appropriateness of the items to sample the "universe of si t u a t i o n s " . The test consists only of those items where at least 75 percent of the s c i e n t i s t s agreed with the keyed response to each item. The instruments* construct v a l i d i t y was determined by investigating the d i r e c t i o n of discrimination among students, s c i e n t i s t s , and science teachers. Nineteen s c i e n t i s t s from Harvard University and Massachusetts Institute of Technology, 16 experienced science teachers, enrolled at the University of Wisconsin and 1,286 students were given the inventory. Through a one-way analysis of variance, i t was found that the instrument discriminated by scoring the s c i e n t i s t s the highest and students s i g n i f i c a n t l y lower. The Welch Science Process Inventory was developed under the auspices of the S c i e n t i f i c Literacy Research Center at the University of Wisconsin. 3.4 Procedural Details Students involved in this study were exposed to treatment during the period between January 4, 1983, and March 25, 1983. - 41 -Prior to this time, l e t t e r s of consent were obtained for the 41 subjects of this study from the students' themselves and their parents (see Appendix A). Following receipt of consent, a random selection was made of the group to represent control and the group to represent the experimental. The a c t i v i t i e s of the control group (Block B) and the experimental group (Block C) w i l l be considered in turn beginning f i r s t with the a c t i v i t i e s of the control group. (A chronological timetable of events that summarize when a c t i v i t i e s took place may be found in Appendix B.) 3.4.1 Control Group A c t i v i t i e s To establish base scores on the understanding of the process of science, the evaluation instrument, the SPI, was administered to the control group as a pretest during the f i r s t week of the study. The SPI was eas i l y administered, requiring no special d i r e c t i o n s . Subjects were merely asked to express agreement or disagreement with each of the statements of the Inventory. Administration of the instrument took 45 minutes, and was thus completed during one class period. Following the administration of the SPI instrument, the students in the control group followed a t r a d i t i o n a l laboratory program using assigned exercises from two laboratory manuals (Investigations of Cells and Organisms by P. Abramoff and R. Thomson, and A Student Laboratory Guide -Bi o l o g i c a l Science by W. Mayer. This program together with - 42 -laboratory manuals have been in use in the Biology 12 course for several years preceding this study. The students, working in groups of two, completed each exercise laboratory in one period. A description of these exercises may be found in Appendix C. These exercises were chosen by the instructor so as to correlate with theoretical lecture material being dealt with in c l a s s . Such lecture material was id e n t i c a l to that given to the experimental groups. In the seven laboratory exercises undertaken by the control group, the experimental procedures, data format and analysis procedure are specified for the students in the laboratory manuals. Thus, the control group were subjected to a highly structured, convergent type of laboratory. The function of the instructor during this laboratory time was to f a c i l i t a t e the smooth operation of those procedures outlined in the laboratory manual. S t r i c t observance of the manual procedures was followed so as not to prejudice student opinion by the off e r i n g of the instructor's viewpoints. A posttest was administered on the l a s t day of the study and the results of this examination were used to determine the change ( i f any) in students' understanding of the process of science. 3.4.2 Experimental Group A c t i v i t i e s Pre and posttesting using the SPI was accomplished in the same fashion and at the same time in the experimental group as in the control group. - 43 -Prior to student laboratory work, the students in the experimental group were instructed in the rudiments of the s c i e n t i f i c method of investigation. During this i n s t r u c t i o n , the students were presented with an example of the application of the s c i e n t i f i c method (see Appendix D). This example, together with a model of the process of s c i e n t i f i c investigation, was used to bring out the following s a l i e n t points concerning the experimental s c i e n t i f i c approach: (a) To observe i s not just to look, but to notice. It requires a focussing of attention. (b) Careful observations lead to interpretations, explanations and predictions. (c) Qualitative observations are distinguished from quantitative observations. During quantitative observing, instruments are used to extend powers of observation. (d) The statement of a problem must be precise and should not try to encompass too general a f i e l d . (e) Hypotheses are based on prior observations or research. (f) Any number of schemes for the testing of hypotheses may be devised. (g) In an experiment, i t is not only the hypothesis which is being questioned; the s k i l l of the experimenter is also under test. (h) A data table must be readily readable and depict a l l quantitative measures taken. - 44 -(i) Reporting results and discussing shortcomings of procedures leads to f i n a l r e f l e c t i o n s on the o r i g i n a l hypothesis. During the ensuing weeks following the pretest and discussion concerning the s c i e n t i f i c method of experimentation, students in the experimental group became engaged in laboratory procedures following theoretical lectures on the process of s c i e n t i f i c investigation. In the laboratory a c t i v i t i e s (outlined in Appendix E) students were allowed to be more f l e x i b l e in the design of their experiments than in the control group. Before student experimentation, the students were presented with 'prior knowledge', which was not given in class lectures which could be used by the students to refine their hypotheses on problems which were c l e a r l y stated. The problems themselves were c a r e f u l l y chosen and worded so that a conclusion was not revealed or implied. In each case d e f i n i t i v e "answers" were not readily obtainable by the students either from previous lectures on subject matter or l i t e r a t u r e research. During student engagement in the process of investigation, the teacher acted as a general guide by asking probing questions and offering c r i t i c i s m s of the students' designs and analyses. The teacher, however, did not " t e l l " the student how to do the experiment or what experiment to do; these decisions were deemed the r e s p o n s i b i l i t y of the student. - 45 -At the end of each laboratory, the students in the experimental group were required to hand in a written report for evaluation. Each report included, (a) a t i t l e , (b) a statement of the problem, (c) formulation of the hypothesis, (d) an outline of experimental procedure, (e) c o l l e c t i o n of data, (f) analysis of data, (g) a discussion, and (h) an ov e r a l l conclusion. The teacher gave the students this outline and provided minimal guidance, but the students were required to make a l l interpretations and evaluations. 3.5 Analysis Technique Following the administration of the posttest of the SPI, raw scores of the 41 subjects were tabulated and the mean is), standard deviation (X) and range for pre and posttests of the control (T 2) and experimental (T-^) groups were calculated. Using this information, a graphical analysis was drawn up of scores as these scores deviated from the means. Data from composite tables of changes in raw scores between pre and posttest were used to: (a) present a graphical analysis comparing T^ changes in score and T2 changes in score. (b) provide a data base for the analysis of covariance (ANCOVA). An ANCOVA was performed so as to control for the effects of students' previous knowledge of the subject. A l l computations were performed at the University of B r i t i s h Columbia Research Computing Center using the BMD03R program -- 46 -Multiple Regression with Case Combinations - Nov. 1972, Health Sciences Computing F a c i l i t y , UCLA. I n i t i a l l y , an ANCOVA was performed using the following o v e r a l l model: Y i j = $ 0 + e l X ± iJ . I + X i j 2 + g 3 X i j 3 + e r j ; i = 1,2...N; j = 1,2 where Y^j is posttest variable ( c r i t e r i o n variable) (dependent variable) independent f^X^-^ i s a treatment vector (X-^ ) variables e 2 x i j 2 i s t h e P r e t e s t variable (X 2) or the covariate ^ 3 X i j 3 "'•s t h e i n t e r a c t i o n variable (Xg)= X-^ X2 E — is the residual difference [Yij - E ( Y ^ ) ] To determine the importance of the covariate interaction (X3), the following test was carried out: F = R\>i*l ~ R 2y.'* / kl" k2 d-R 2 y. 1 2 3) /n-3-1 where: 2 Ry.l23 = a m o u n t o r variance in Y due to a linear combination of X-^ , X 2 and X3. 2 R^.12 = amount of variance in Y due to a linear combination of X-^ , and X 2. k-^  , k 2 = n-k-1 degrees of freedom n = t o t a l number of subjects in the two groups - 47 -The decision rule, i f F>,^^ir27' Ho maY be rejected, was followed. To test for treatment e f f e c t s , the following s t a t i s t i c a l test was conducted to test the s t a t i s t i c a l hypothesis, H o : (S ! = 0 at the©C= 0.05 l e v e l : F = RY.12 " R Y . 2 / : L ( 1 - R Y . I 2 ) / 3 8 F i n a l l y , using the adjusted posttest scores (^) a <^j individual regression l i n e s for each group were drawn and the difference discussed. The v a l i d i t y and r e l i a b i l i t y of the results of this study are dependent, in part, upon the v a l i d i t y of the following assumptions: 1. The instrument employed in this study possesses adequate v a l i d i t y and r e l i a b i l i t y for the purposes for which they were employed. 2. The inherent assumptions of analysis of covariance such as homogeneity of regression were not seriously v i o l a t e d . - 4 8 -CHAPTER IV ANALYSIS OF DATA AND RESEARCH FINDINGS 4 . 0 INTRODUCTION The results of the analyses described in Chapter Three are presented in this chapter. These analyses evaluate the effectiveness of two methods of laboratory instruction in b i o l o g i c a l science - the highly structured t r a d i t i o n a l laboratory method and the more f l e x i b l e investigative-based laboratory method. 4 . 1 Description of Research Findings Raw scores from the administration of the SPI instrument may be found in Appendix F. From the calculated mean values i t is apparent that posttest scores generally varied l i t t l e from pretest scores for the control group (a change of 0 . 1 9 ) whereas a change of 2 . 9 5 in the mean scores between pre and posttest was recorded for the experimental group. Whether this change is s t a t i s t i c a l l y s i g n i f i c a n t was determined using the ANCOVA model. A graphical analysis of deviations in score from the means may be found in Appendix G (figures 1 , 2 , 3 and 4 ) . The composite graph comparing changes from pre to posttest scores for the experimental (T-^ ) and control groups ( T o ) i s indicated (Fig. 5 ) . h H r f P5= 1-1-- t - H -4 - t - f --t-r -01 -fi>4 - I O > L . A^ 8° 35 - t ~ t - ^ &0 -+-e-t-r A 4-A-A loo) •A-A~ -0-A //,» LA_L_ -M--+-- 50 -The scattered points found on this graph were f i t t e d by least-square regression lines l a t e r in this analysis. Of p a r t i c u l a r note are two data points (Tj - 125/110 and T 2 -112/100) that markedly deviate from the general l i n e a r tendency of data points. These points w i l l be seen to have the highest residual error in the estimated regression l i n e s (-15.481 and -11.556 r e s p e c t i v e l y ) . 4.1.1 Analysis of Covariance (ANCOVA) Raw data scores for Y of T 2 were given codes of 1 and -1 respectively, the data outlay of which may be seen on Table 6 (Appendix H). These scores were then used to estimate the ove r a l l regression model on which the ANCOVA was based. From the analysis of the f u l l model the following results were obtained: (a) Ry.123 = ° « 8 9 (b) e^j are generally low (range 23.64) Thus, extraneous variables are seen to have a very low e f f e c t on the dependent variable (Y) . Indeed * 89% of the variance in Y was due to factors X-^ t X 2 and X 3 . Using the test s t a t i s t i c indicated in Chapter Three we get the r e s u l t : -F = 0.8903 - 0.8893/1 (1-0.8903) /37 F = 0.34 - 51 -since F>.95 Fi,37 then H Q i s tenable and the reduced model may be adopted. Thus, there is no difference in the performance on the c r i t e r i o n measure due to interaction between the treatment effects and the covariate. 4.1.2 F-Test Ratio Treatment effects calculated below in Table 8 from the reduced model indicate that: (a) covariate e f f e c t constitutes - 87% of the t o t a l v a r i a t i o n in Y scores. (b) treatment effects constitute - 2% of the to t a l v a r i a t i o n in Y scores. (c) residual effects constitute - 11% of the t o t a l v a r i a t i o n in Y scores. TABLE 8 TREATMENT EFFECTS  Source of Variation Proportion of Variation Degrees of Freedom Covariate (X ) R 2 = 0.87 Y . l 1 Treatment Eff e c t (X ) RY.12-RY.2 = 0 ' 0 2 1 Residual (1-4.12 } = 0 ' X 1 38 Total 1.00 Using the F-test of significance s t a t i s t i c referred to in Chapter 3: F = 0.8893 - 0.8720 (1-0.8893) /38 F = 5.97 - 52 -Since F > 95F-L 3c. then H Q may be rejected. Thus, there is a s i g n i f i c a n t difference, at the .05 l e v e l , in the performance on the c r i t e r i o n measure due to the effects of the treatment variable. 4.1.3 Graphical Analysis Regression lines of T^ and T 2 data can be drawn using the o v e r a l l estimated regression equation:-\ l = b o + ^ X ± j l + b2 X i j 2 TABLE 9 CALCULATIONS OF ESTIMATED POSTTEST SCORES Treatment X l Y; T 1 (bfl + b ) + b 2 X 2 = 19;*5 + 1.5) + 0.8 X? T 1 (b - bi) + b 2 X ? = riQ.S - 1.5) + * 0.8 X?. Equations for T-L and T 2 1inear variations are: (T x) / N . Y l = 0 .80X2 + 21.0 <T2) Y 2 = 0 .80X2 + 18 .0 Thus, the slope of both regression lines i s 0.8. The Y-intercept for T1 = 21.0 and for T 2 = 18.0 (Fig. 6) The difference between the Y-intercept of the two regression lines represents the eff e c t of the treatment variable on the c r i t e r i o n v a r i a b l e . This difference was shown to be s i g n i f i c a n t at the <*<.05 l e v e l . - 54 -CHAPTER V CONCLUSIONS, LIMITATIONS AND RECOMMENDATIONS 5.0 Introduction This study originated from the author's desire to test empirically the effects of an author-designed i n v e s t i g a t i v e -based laboratory program on student understanding of the process of science. In response to d i s s a t i s f a c t i o n with contemporary laboratory a c t i v i t i e s , there have been many innovative attempts to develop i n s t r u c t i o n a l laboratory a c t i v i t i e s which are more c h a r a c t e r i s t i c of the nature of science. However, at least in biology, the quantitative evaluation of the effectiveness of these innovations has been the exception rather than the ru l e . So there now exists an urgent need for both innovation of new laboratory a c t i v i t i e s and evaluation of their i n s t r u c t i o n a l effectiveness. This study deals with the evaluation of the r e l a t i v e effectiveness of a t r a d i t i o n a l laboratory program and a more f l e x i b l e , investigative-based laboratory program. These laboratory a c t i v i t i e s were part of a biology 12 secondary school program at a Senior Secondary School during three months of the school year 1982/83. One group, the control group, followed a t r a d i t i o n a l laboratory program using exercises from a conventional laboratory manual. The other group followed a more f l e x i b l e program which emphasized student involvement in hypothesising, experimental designing - 55 -and the discussing of research findings. Intact classes were used since the r e g i s t r a t i o n procedure precluded assignment of students to s p e c i f i c classes; thus, random selection was not presumed in the study. A quasi-experimental nonequivalent control group design was used with the Welch Science Process Inventory used to measure student understanding of the process of science. S t a t i s t i c a l analysis performed by an analysis of covariance computer program was used to minimize any bias due to prior knowledge about the science process. 5.1 Conclusions Based upon the re s u l t s from the analysis of data i t may be concluded that the n u l l hypothesis stipulated in Chapter One may be rejected. That i s , students involved in a laboratory program that emphasized more involvement in student-directed investigations achieved a s i g n i f i c a n t l y better understanding of the actions and operations of s c i e n t i s t s than students in a t r a d i t i o n a l laboratory program. However, i t should also be noted that only 2% of the variance in Y was accounted for by the treatment e f f e c t s . Other, more subjective conclusions that are borne out of this study come from the author's ethnographic observations, and, although not based on an analysis of quantitative data, are considered s a l i e n t points to be expressed. These conclusions are: - 56 -1. Most of the students in the investigative-based program enjoyed these a c t i v i t i e s more than their p r i o r experiences with t r a d i t i o n a l laboratory programs. (The degree to which in-class discussions contributed to this apparent increase in le v e l of motivation remains unknown.) 2. The length of time required to complete laboratory a c t i v i t i e s for the experimental group exceeded that for the control group. 3. Although the length of time required to complete laboratory a c t i v i t i e s was greater for the experimental group, with an increase in time i t was found that a great deal more was accomplished in the class time given for experimentation. 4 . The amount of apparatus required for the experimental group was greater and of a more diverse nature than that required for the control group. This necessitated greater preparation time for the instructor. 5. Evaluation of laboratory reports from the experimental group was found to be more d i f f i c u l t and time consuming for the instructor. Such reports, which included a detailed descriptions by the students of procedural methods and, often, lengthy discussions of resu l t s , were often d i f f i c u l t to assess as to their merits. Control group reports - 57 -tended to be more cursory, simply offering answers to stated questions from the prescribed laboratory manuals. 6. During laboratory classes there were often as many as six or seven quite d i f f e r e n t procedures taking place at once in the experimental group. This made i t d i f f i c u l t for the instructor to monitor a l l of the students' experimental designs. 5 .2 Limitations Measuring understanding of the process of science is a matter of assigning quantitative scores to subjective responses. These responses are sensitive to external influences. The i d e n t i f i c a t i o n of these influences and the ef f e c t they have on experimental results is a continuing problem in aff e c t i v e research. This study was limited to grade 12 students and was carried out over a r e l a t i v e l y short period of three months. What eff e c t the investigative-based laboratory method has on students' understanding of the process of science when this method is used over longer time periods or with other grades has not been investigated. The results of this study must therefore be used with caution when attempting to generalize outside the population studied. The involvement of the investigator as the teacher in this study introduced a possible error as the investigator - 58 -possesses a bias towards the investigative-based method of laboratory teaching. It has been shown (Rosenthal and Fode, p.163) that i f the researcher has a strong expectancy that his innovation i s superior to conventional practice, his experiment might y i e l d this finding. The use of a r e l i a b l e and non-instructor designed instrument together with an analysis of covariance, and researcher avoidance of the suggestion to subjects that one experimental treatment was better than another; may have minimized, to some degree, this experimenter bias e f f e c t . The lack of random assignment of subjects l i m i t s the internal v a l i d i t y of this study. However, this random assignment is not recognized as a major problem the more similar the experimental and control groups are in t h e i r recruitment, as reflected in the s i m i l a r i t y in pretest means: In p a r t i c u l a r i t should be recognized that the addition of even an unmatched or nonequivalent control group reduces greatly the equivocality of interpretation s over what is obtained in Design 2, the One-group Pretest-Posttest Design. [True experimental design] (Campbell and Stanley, 1963, p.47) 5.3 Recommendations 1. Innovation, development and evaluation of new laboratory programs should be continued. 2. Incorporation of increased student involvement in the process of s c i e n t i f i c investigation should be considered for at least some laboratory experiences in secondary schools. These laboratory experiences - 59 -do possess some unique advantages. 3. This study should be replicated with more heterogenous populations and at other i n s t i t u t i o n s . 4 . A study needs to be conducted, involving several instructors, both p a r t i a l and impartial, to determine the instructor's interest as a motivating factor in building student understanding of science processes in the laboratory. Or, a r e p l i c a t i o n of this study may be made with removed biases. 5. A similar study needs to be conducted, over a longer period of time, to determine i f retention of understanding is increased in laboratory work. 6 . The e f f e c t of the investigative-based laboratory method on other areas of science: areas such as chemistry, physics and earth science, needs to be investigated. 5 .4 Epilogue It was hoped that by exposing science students to an investigative laboratory program they would emerge from the laboratory with some understanding of the problems and operations of a s c i e n t i s t . It was hoped that they would begin to f e e l their dependence on a framework that establishes, designs and d i r e c t s experiementation, that they would learn the l i m i t s of both their perceptual senses and thinking a b i l i t i e s and see the usefulness of various instruments that - 60 -could help them solve the problem. It was hoped that they would develop an experiment to generate data that could be used to decide the v a l i d i t y of their hypotheses and then to tenta t i v e l y accept, restate in a modified form or discard what was chosen to be the best hypothesis. Within the limited confines of this study, these aspirations seem to have been accomplished. - 6 1 -BIBLIOGRAPHY Abramoff, P., and Thomson, R.G. Investigations of c e l l s and  organisms. Scarborough, Ont.: Prentice-Hall, 1 9 7 8 . Abramoff, P., and Thomson, R.G. Investigations of c e l l s and  organisms (Teacher's Manual). Scarborough, Ont.: Prentice-Hall, 1 9 7 9 . Aikenhead, G.S. The measurement of high school students' knowledge about science and s c i e n t i s t s . Science  Education, 1 9 7 3 , 5 7 r 5 3 9 - 5 4 9 . A l l i s o n , R.O. An investigation into the attitudes toward science of college chemistry students as a function of laboratory experience. Dissertation Abstracts, 1 9 7 3 , 2 8 , 4 9 2 7 . Andersen, H.O. Readings in science education for secondary  schools. New York: Collier-Macmillan, 1 9 6 9 . Andersen, H.O., and Weigand, J.E. Instructional theory, problem-solving and science teaching. School Science and  Mathematics, 1 9 6 7 , J5_7 , 4 8 3 - 4 9 0 . Ausubel, D.P. A cognitive structure theory of school learning. In L. Siegel (Ed.), Instruction: Some  contemporary viewpoints. Sanfrancisco: Chandler Publishing, 1 9 6 7 . Bady, R.J. Students' understanding of the logic of hypothesis te s t i n g . Journal of Research in Science Teaching, 1 9 7 9 , 1 6 , 6 1 - 6 5 , Bady, R.J., and Engeart, M.A. 'Try and prove i t ' : an exercise in the logic of science. The Science Teacher, 1 9 7 8 , Dec., 3 6 - 3 7 . Baxter, K.W. A comparative study of the effectiveness of three methods of teaching a general physical science course. Dissertation Abstracts, 1 9 6 9 , 30_, 4 8 2 - A . Beisenherz, P.C, and Olstad, R.G. The use of laboratory ins t r u c t i o n in high school biology. The American Biology  Teacher, 1 9 8 0 , j 4 2 _ , 1 6 6 - 1 7 5 . Beveridge, W.I.B. The Art of s c i e n t i f i c investigation. London: Heinemann, 1 9 5 0 . B i l l e h , V.Y., and Malik, M.H. Development and application of a test on understanding the nature of science. Science  Education, 1 9 7 7 , 6 1 , 5 5 9 - 5 7 1 . - 62 -Blosser, P.E. A c r i t i c a l review of the role of the laboratory  in science teaching. Columbus, Ohio: Clearinghouse for Science, Mathematics and Environmental Education, 1981. Bock, J.S. A comparison of the effects of an inquiry-investigative and a t r a d i t i o n a l laboratory program in high school chemistry on students' a t t i t u d e s , cognitive a b i l i t i e s and developmental l e v e l s . Dissertation Abstracts, 1980 , 4J ) , 6220-A. Boohar, R.K. Investigative laboratories for high enrollments and low budgets. Journal of College Science Teaching, 1975, 5, 261-263 . Borg, W.R., and G a l l , M.D. Educational Research. New York: Longman, 1979. Buros, O.K. The f i f t h mental measurements yearbook. Highland Park, New Jersey: The Gryphon Press, 1959. Cannon, R.A. A comparison of two laboratory methods investigating interest and the understanding of the process of science in a general education physical science course. Dissertation Abstracts, 1976, 36 , 4379-A. Campbell, T.C. An evaluation of a learning cycle intervention strategy. Dissertation Abstracts, 1978, 3S_, 3903-A. Campbell, P.T., and Stanley, J.C. Experimental and quasi-experimental designs for research. In N.L. Gage (Ed.), Handbook of research on teaching. Chicago: Rand McNally, 1963. Cooley, W. and Klopper, L.E. The evaluation of s p e c i f i c educational innovations. Journal of Research in Science  Teaching, 1963, _1 , 73-80 . Creager, J.G. Biology laboratory manual. New York: Macmillan, 1981. Damewood, J.C. Evaluation of a physical science course for prospective elementary teachers in terms of competence attained in the process of science. Dissertation  Abstracts , 1971, 32_, 3112. Dawson, J.C. An investigation of the effects of two i n s t r u c t i o n a l strategies. Dissertation Abstracts, 1975, 36, 3538A. Edgar, I.T. A study of the effects of laboratory centered instruction on student c r i t i c a l thinking s k i l l s . Dissertation Abstracts , 1969 , 29, 3910A. - 63 -Egelston, J. Inductive vs. t r a d i t i o n a l methods of teaching high school biology laboratory experiments. Science  Education. 1973, J57_, 467-477. Gardner, M. Trends in development and implementation of science curriculum in the U.S.A. New York: Macmillan, 1979. Herron, J.O. A summary of research in science education. Science Education, 1975, 12, 338-357. Hobbs, E.D. (Ed.) B r i t i s h Columbia science assessment:  summary report. B.C. Government Prin t e r , 1978. Hoff, D.B. A comparison of a directed laboratory versus an enquiry laboratory to general education college astronomy, Dissertation Abstracts, 31, 2755A. Hofstein, A., and Lunetta, V.N. The role of the laboratory in science education. Review of Educational Research, 1982, 52, 201-217. Hurd, P.D. New directions in teaching secondary school  science. Chicago: Rand McNally, 1969. Isaac, S. Handbook in research and evaluation. New York: Macmillan, 1978. Kennedy, M.H. B i o l o g i c a l science: interaction of experiments  and ideas. Englewood C l i f f s , N.J.: Prentice-Hall, 1977. Kenny, D.A. A quasi-experimental approach to assessing treatment effects in the nonequivalent control group design. Psychological B u l l e t i n , 1975, 8_2, 345-362. Klein, S.E., Yager, R.E., and McCurdy, D.W. The laboratory i s v i t a l in science instruction in the secondary school. The Science Teacher, 1982, jl9. 20-23. Kramm, K.R. Research and laboratory inst r u c t i o n . Journal of  College Science Teaching, 1974, j l , 174-175. Lawson, A.E., Blake, J.O., and Nordland, F.H. Training e f f e c t s and generalization of the a b i l i t y to control variables in high school biology students. Science  Education, 1975 , J59_, 387-396. Layton, D. Science for the people. New York: Science History Publications, 1974. - 64 -Levine, D.I., and Linn, M.C. S c i e n t i f i c reasoning a b i l i t y in adolescence: theore t i c a l viewpoints and educational implications. Journal of Research in Science Teaching, 1977, 1±, 371-384. Lewis, R.W. How to write laboratory studies which w i l l teach the s c i e n t i f i c method. Science Education, 1947, 31, 14-17. Linn, M.C, Chin, B. , and Thier, H.O. Teaching children to control variables: investigation of a free-choice environment. Journal of Research in Science Teaching, 1977, L4, 249-255. Lucas, A.M. Hidden assumptions in measure of knowledge about science and s c i e n t i s t s . Science Education, 1975, 59 , 481-485. Lucy, E.C An evaluation of a laboratory science program in a professional education course for prospective secondary science teachers. Dissertation Abstracts, 1973, 33, 6197. Lunetta, V.N., and Tamir, P. An analysis of laboratory a c t i v i t i e s in two modern science c u r r i c u l a , Dissertation  Abstracts, 1978 , 25.' 3359A. Mackay, L.O. Development of understanding about the nature of science. Journal of Research in Science Teaching, 1971, 8, 57-66. Magnus, D.L. A comparison between teacher-directed instruction and student s e l f - d i r e c t e d study in physical science for undergraduate elementary education majors. Dissertation Abstracts, 1973, 34_, 3214. Manteuffel, M.S., and Laetsch, W.M. Problem formulation in undergraduate biology student investigations. Journal of College Science Teaching, 1981, JL£, 160-163. Mayer, W. B i o l o g i c a l science: an inquiry into l i f e : student  laboratory guide. New York: Harcourt, Brace and World, 1968. Mayer, W. B i o l o g i c a l science; an inquiry into l i f e : teacher's manual. New York: Harcourt, Brace and World, 1969. Mayer, W. (Ed.) Biology teachers' handbook. New York: John Wiley and Sons, 1978. M i t c h e l l , D.A. The production of c r i t e r i a for evaluating science curriculum materials. Research in Science  Education, 1978, 8, 59-69. - 65 -Moll, M., and Alle n , R.D. Student and graduate teaching assistant response to investigative laboratories. Journal of College Science Teaching, 1982, 11, 219-222. Moshman, D., and Thompson, P.A. Hypothesis teaching in students: sequences, stages and instructional strategies. Journal of Research in Science Teaching, 1981, 18^, 341-352. Mouly, G.J. Educational Research. Boston: All y n and Bacon, 1978. Munby, H. What is s c i e n t i f i c thinking. Ottawa, Ontario: Publications Office of the Science Council of Canada, 1982. Nedelsky, L. Science teaching and testing. New York: Harcourt, Brice and World, 1965. Nelkin, D. Science textbook controversies and the p o l i t i c s of  equal time. Cambridge, Mass.: MIT press, 1978. Olstad, R.G. The e f f e c t of science teaching methods on the understanding of science. Science Education, 1977 , 21, 9-12. Pare, R.R., and Butzow, J.W. The relationship among independence of work habits, attitude and achievement in an audio-tutorial physical science course. Journal of  Research in Science Teaching, 1975, _12, 1-30. Pavelich, M.J., and Abraham, M.R. An inquiry format laboratory program for general chemistry. Journal of  Chemical Education, 1979, 100-103 . P e l l a , M.O. C r i t e r i a for good experimental research in the teaching of science. Science Education, 1961, 45, 396-399 . Pickering, M. Are lab. courses a waste of time? Journal of  College Science Teaching, 1980, 11, 210-211. Raghubir, K.P. The laboratory-investigative approach to science i n s t r u c t i o n . Journal of Research in Science  Teaching, 1979, 16_, 13-17. Ramsey, G.A., and Howe, R.W. An analysis of research on i n s t r u c t i o n a l procedures in secondary school science. The Science Teacher, 1969, J36_, 72-81. Rasmussen, F.A. Matching laboratory a c t i v i t i e s with behavioral objectives. B i o l o g i c a l Science, 1970 , 20 , 292-294. - 66 -Rickert, R.K. The c r i t i c a l thinking a b i l i t y of college freshman physical science students: a study of the relationship between the development of the c r i t i c a l thinking a b i l i t y of college freshman physical science students and science course organization, i n i t i a l s k i l l in science and general college a b i l i t y . Dissertation  Abstracts, 1962, _52, 1449. Rogers, R. A comparison of two methods of science instruction in a college general studies program. Dissertation  Abstracts, 1972, 32^, 4252. Romey, W.O. Inquiry techniques for teaching science. Englewood C l i f f s , N.J.: Prentice-Hall, 1968. Rosenthal, R. Experimenter effects in behavioral research. New York: Appleton-Century Crofts, 1966. Scott, F.W. A study in teaching s c i e n t i f i c method and attitude in the junior high school. Science Education, 1940, 2 ± , 30-35. S e r l i n , R.C. The effects of teaching a general biology course using auto-tutorial or a lecture-laboratory method. Dissertation Abstracts, 1977 , 37.' 5729A. Sherman, J.E. The r e l a t i v e effectiveness of two methods of u t i l i z i n g laboratory-type a c t i v i t i e s . Dissertation  Abstracts, 1969, 29_, 4319A. Smith, A.E. An experimental study of the use of an extended laboratory problem. Dissertation Abstracts, 1971, 32, 1403A. Smith, M.O. A comparison of two laboratory methods for the teaching of general physical science at the college l e v e l : vicarious experimentation versus conventional experimentation. Dissertation Abstracts, 1971, 32, 5116A. Sorensen, L.L. Change in c r i t i c a l thinking between students in laboratory centered and laboratory centered i n s t r u c t i o n . Dissertation Abstracts, 1966 , 26_, 6567A. Spears, J . , and Zollman, D. The influence of structured versus unstructured laboratory on students' understanding of the process of science. Journal of Research in  Science Teaching, 1977 , 14_, 33-38 . Stake, R.W., and Easley, D.L. Case studies in science education. New York: MacMillan, 1980. - 67 -Stanley, J . C , and Hopkins, K.D. Educational and psychological measurement and evaluation. Englewood C l i f f s , N.J.: Prentice H a l l , 1972. Stekel, F.D. The effects of increasing the student involvement in a college physical science laboratory program. Dissertation Abstracts, 1971, J3_l, 5880A. Stothart, J.R., and Bingham, R.M. LEIB-IRA: preliminary report. The American Biology Teacher, 1972, 25, 346-348. Tamir, P. The p r a c t i c a l mode in schools. School Review, 1975, j53_, 499-506. Tamir, P. How are laboratories used? Journal of Research in  Science Teaching, 1977, L4_, 311-316. Tamir, P., and Lunetta, V.N. Inquiry-related tasks in high school science laboratory handbooks. Science Education, 1981, £5, 477-484. Tanner, R.T. Expository-deductive versus discovery-inductive programming of physical science p r i n c i p l e s . Journal of  Research in Science Teaching, 1969 , 6^, 142-148 . Tawney, D.A. The nature of science and s c i e n t i f i c inquiry. In Sutton, CR., and Hayson, J . J . (Eds), New York: McGraw-Hill, 1974. Welch, W.W., and P e l l a , M.O. The development of an instrument for inventorying knowledge of the processes of science. Journal of Research in Science Teaching, 1968 , _5, 64-68 . Welch, W.W., and Walberg, H.J. An evaluation of summer i n s t i t u t e programs for physics teachers. Journal of  Research in Science Teaching, 1968 , _5 , 64-68. Wheeler, S.E. Critique and revisi o n of an evaluation instrument to measure students' understanding of science and s c i e n t i s t s . Science Education, 1968, j>_2, 172-179. White, R.T. Relevance of p r a c t i c a l work to comprehension of physics. Physics Education, 1979, _14 , 384-387. White, R.T. Comment on the laboratory-investigative approach to science i n s t r u c t i o n . Journal of Research in Science  Teaching, 1980 , 17_, 359-360. - 68 -A P P E N D I X A Sample l e t t e r s of Consent - 69 -Richmond Sr. Sec. School Letterhead Dear Parent/Guardian, In a d d i t i o n to being your son/daughter's b i o l o g y teacher, I am a l s o a part-time graduate student at U.B.C. (Science Education Department). I have given your son/daughter a consent form f o r a study I wish to conduct to determine the e f f e c t i v e n e s s of a new l a b o r a t o r y method I have designed. Such a method w i l l a l l o w students more p a r t i c i p a t i o n i n the design of t h e i r b i o l o g y experiments and a l l o w them to discuss t h e i r r e s u l t s i n a manner that I hope w i l l r e s u l t i n a b e t t e r understanding of the processes of science. The students w i l l be separated i n t o a c o n t r o l and experimental group w i t h the c o n t r o l group simply f o l l o w i n g t r a d i t i o n a l lab methods from the p r e s c r i b e d lab t e x t and the experimental group f o l l o w i n g my lab design. Your son/daughter w i l l be i n the g r o u P -P a r t i c i p a t i o n i n my f i e l d of study i s s t r i c t l y on a volunteer b a s i s and w i l l take place between January 4 and March 31, 1983. R e f u s a l to p a r t i c i p a t e or withdraw from the study w i l l not j e o p a r d i z e c l a s s standing of the s u b j e c t s . Students who do not p a r t i c i p a t e i n the study w i l l complete the c l a s s a c t i v i t i e s as scheduled but w i l l not w r i t e the pre/post t e s t . As parent/guardian, i f you consent to your son/daughter's p a r t i c i p a t i o n i n my study please i n d i c a t e by s i g n i n g the p o r t i o n below and r e t u r n i n g i t to Mr. McCarthy by m a i l . (Richmond Sr. Sec. School, 7171 Foster Road). __ consent to have my son/daughter p a r t i c i p a t e i n Mr. McCarthy's study as described above. - 70 -Richmond Sr. Sec. School Letterhead Dear Student: As you are aware by now, I am a graduate student at the U n i v e r s i t y of B r i t i s h Columbia (Science Education Department), as w e l l as your b i o l o g y teacher! To complete my t h e s i s requirements, I have designed a f i e l d experiment that r e q u i r e s v o l u n t e e r s . That i s where you come i n ! For one of my b i o l o g y 12 b l o c k s , I w i l l be using an a l t e r n a t e l a b o r a t o r y method to the one you normally use ( i . e . the one from your l a b t e x t ) f o r the months of January, February and March. This lab method w i l l r e q u i r e students to design t h e i r own experiments, hypothesize and discuss t h e i r r e s u l t s . As a c o n t r o l , I w i l l have the other b i o l o g y 12 block continue as we have done t h i s year - using the t r a d i t i o n a l method of l a b i n s t r u c t i o n from the lab t e x t . At the beginning and end of the study, a t e s t q u e s t i o n n a i r e w i l l be administered that w i l l measure students' understanding,of the processes of science. Re f u s a l to p a r t i c i p a t e or withdraw from the study w i l l not j e o p a r d i z e your c l a s s standing. I f you do consent, please i n d i c a t e by s i g n i n g the s e c t i o n below and r e t u r n i n g i t to me as soon as p o s s i b l e . 1' _ . consent to p a r t i c i p a t i n g i n Mr. McCarthy's study as described above. - 71 -APPENDIX B O v e r a l l T i m e t a b l e o f E v e n t s - 72 -Activity DATE J 4-7 J 10-14 J 17-21 J 24-28 Class Period 1 2 1 2 3 1 2 3 1 2 3 Control 1 A, ® 2 3 © 4 5 6 7 8 Exp 1 A, © ) G ) 2 3 © © 4 5 6 Activity DATE J 31-4F F 7-11 F 14-18 F 21-25 Per. 1 2 3 1 2 3 1 2 3 1 2 3 C (D 19 10 11 12 0 13 14 15 © 16 17 E 7 8 (3) (3) 9 10 11 12 (4) 13 14 15 Activity DATE F 28-4 M M 7-11 M 14-18 M 21-25 Per. 1 2 3 1 2 3 1 2 3 1 2 3 C 18 © 19 20 21 © 22 23 24 25 © A^ E (J) 16 17 18 (6) (e) 19 20 21 ® 22 A, In A Chronologically Ordered Sequence - Circled Numbers = Lab Activities - Uncircled Numbers = Lectures, Mic. Examination Work, Guest Speakers, Tests - A L = SPI pretest - A 9 = SPI posttest Chronological Sequence of  Events during treatment period Jan. 4 to March 25. - 73 -APPENDIX C A c t i v i t i e s i n t h e C o n t r o l G r o u p ' s T r a d i t i o n a l L a b o r a t o r y p r o g r a m . - 74 -INQUIRY EfOTE IHPLAMT AMD ANIMAL TISSUE In Inquiry 4-1 you found that certain reac-tions were speeded up by the action of the enzyme diastase. In this inquiry you will in-vestigate the enzyme catalase (CAT-a-lace) in various tissues. One of the questions you will attempt to answer is whether catalase is present in all the tissues with which you will work. MATERIALS 2 test tubes A variety of animal and plant tissues: fresh beef, pork, or lamb liver and kidney; worm tissues; frog blood; po-tato; apple; etc. 3 percent hydrogen peroxide (H 20 2) solution Graduated cylinder, 25-50 ml Thermometer, 0 ° - 1 0 0 ° C Vial 95 mm long X 25 mm external diameter One-holed stopper, No. 4 size Forceps Paper toweling Bunsen burner or other heat source E X P E R I M E N T A L D E S I G N On a demonstration table are slices of various plant and animal tissues, with labels for easy identification. D o not touch the samples at any time with your fingers, for you do not want to 32 introduce substances from your own skin tis-sue. Use the forceps to take a piece of each of the tissues and place it on a piece of paper toweling. Keep each piece apart from the others on the towel, and label the towel for their identification. On a second piece of paper toweling take identical tissues which have been boiled. Again handle the tissues with your forceps. Take two clean test tubes and pour 5 ml of fresh 3 percent hydrogen peroxide solution into each tube, (CAUTION: Hydrogen peroxide, if spilled on clothing, will produce discohra-tions.) Select an untreated and a boiled tissue sample of the same tissue, and with the forceps place one of them in each tube. • Observe and record the results [1]. Empty the tubes, rinse them, and again pour 5 ml of fresh 3 per-cent hydrogen peroxide solution into each tube. Proceed as before with another tissue pair. Continue in this manner until you have tested all tissue pairs and have added the re-sults to your record for the first pair. Catalase is an enzyme that breaks down hydrogen peroxide, forming oxygen and water. • How does each sample tissue you tested indicate the presence or absence of catalase in the tissue [2]? Prepare a list of the tissues beginning with the one showing the greatest catalase activity and continuing in order of decreasing catalase activity. Which of the tissues are most active in catalase activity [3]? • least active [4]? >- What, if anything, do the - 75 -tissues at opposite ends of the list have in common [5]? • W h a t do your data indicate about catalase activity in boiled and untreated tissues [6]? Hydrogen peroxide is frequently used as an antiseptic. When poured on an open wound, it begins to bubble. • What does this indicate to you about human tissues [7]? If you held the test tubes with your fingers during the preceding reactions, were you able to notice changes other than the production of bubbles? In many chemical reactions both in the laboratory and in living organisms, some of the energy is given off as heat. We measure heat in units called calories and kilo-calories (1000 calories). One calorie is the amount of heat required to raise the tempera-ture of 1 g of water 1°C* A device frequently used to measure this heat is a calorimeter (cal-o-RiM-cter). Figure 15 shows the type of calorimeter you will construct for this investi-gation. Set up the calorimeter and place 10 ml of hydrogen peroxide in the reaction chamber. Moisten the thermometer, pass it through the hole in the rubber stopper, lower it into the hydrogen peroxide, and record the initial tem-perature. Note that the definition of a calorie is in terms of water, not of hydrogen peroxide. • What assumptions does this suggest you are going to have to make about the use of hydro-gen peroxide in this inquiry [8]? • Why should you be concerned with the basic as-sumptions for this or any other scientific inquiry [9]? Before proceeding further, read the remain-der of the experimental design and set up your controls for this inquiry. After you have measured the initial tempera-ture of the hydrogen peroxide in the reaction chamber, introduce two drops of liver extract (which your teacher will supply to you) into • This definition of calorie is the true one, not the "calorie" used by nutritionists in discussing food values. The latter actually is the lu'localorie. the chamber with the 10 ml of hydrogen perox-ide. Insert the cork into the vial loosely to allow any gas generated to escape. Record the temperature change in the reaction chamber every 30 seconds for a period of at least 5 minutes. Repeat this procedure at least two more times with fresh hydrogen peroxide and liver extract. • W h y [10]? Take the average of your three temperature measurements for each time interval of 30 seconds. Record the results of each time trial and the trial averages in a data table, and then graph this data. • By reference to your data and graph, what is the total temperature change that occurred in the reaction chamber [11]? • How many calories of heat does this temperature change represent [12]? • If your graph reaches a A - 0-100° C thermometer -One-holed stopper (to be loosened during use of calorimeter with H 20 2) -Vial (25x95 mm) -Reaction chamber -10ml of 3 percent HJOJ solution 1 5 A glass-vial calorimeter 33 plaU-au, what might ihis indicate about the rate oi reaction [13]? t> If the graph indicates that the temperature is decreasing after an initial increase, what should this indicate about the reaction [14]? • What is the source of the heat measured in this inquiry [15]? Consider the data further. The reaction of catalase with hydrogen peroxide takes place in the human body as well as in other animals and plants. • Does all energy resulting from biochemical reactions appear as IK-at'.' F.xplain [16J. The temperature of the liver of the mammal from which the liver extract was taken was probably about 38° C. What would happen to the activity of catalase if the liver temperature were increased briefly (for 3 to 5 minutes) to 50° C? 55° C? 60° C? Design and carry out an experiment that will give you answers to this question. - 77 -EACTIOW In Inquiry 6-4 you discovered some princi-ples of diffusion in a model of a cell. How do the principles apply to a living cell? How is a cell's Internal environment affected when change in and around it occurs constantly? MATERIALS Part A 5 ml suspension of yeast cells (freshly prepared) for each group of 2 to 4 students Congo red solution Microscope slide Cover glass 2 test tubes Test tube rack Compound microscope Bunsen burner Test tube holder Beaker Part B Sprig of elodea 5 percent sodium chloride (NaCl) solu-tion Compound microscope Microscope slide Cover glass Paper toweling or filter paper Medicine dropper (pipette) Glass of water Glass for NaCl solution E X P E R I M E N T A L D E S I G N Part A. Diffusion in a Uniform Environment Place 1 ml of yeast suspension in each of two test tubes. A d d 3 drops, of Congo red solution to each test tube. Heat the contents of one test tube to the boiling point in a beaker of boiling water, then extinguish the burner. Prepare wet mounts of both yeast suspen-sions and examine- under low and high power. • Describe the differences you observe in the two suspensions [1]. • How do you ac-count for these differences in terms of the way the yeast cells were treated [2]? • What hypothesis can you offer about cell membranes and diffusion on the basis of this inquiry [3]? g i n g Part B. Diffusion in a Changi Environment The closely regulated environment inside an elodea cell contains a concentration of approxi-mately 0.9 percent sodium chloride (table salt). If the cells are in water that is also near this concentration of salts, no special problems oc-cur. • But what do you think will happen if you place a higher concentration of salt solu-tion around the outside of the cells [4]? Place a leaf from a growing tip of elodea in a drop of tap water on a clean slide. Add a cover glass and study it under low power and high power. Now place a small bit of paper 51 - 78 -toweling or filter paper at one edge of the cover glass to draw the water off the leaf. Add a drop of salt solution on the opposite side of the cover glass. It will be drawn under the cover glass as the water already there is drawn off by the paper towel or filter paper. Observe the effect on the cells as the salt water moves over the leaf. • Describe what you see taking place j within the cells [5].. j What will happen to-the cells if the leaf is j . washed and again placed in plain water? Re-< move the leaf and place it in a glass of water. I '•• Study it again under the microscope after a period of 5 minutes. • R e c o r d any changes i ' , you observe [6]. j • Will the plant die if allowed to remain in an i unbalanced salt environment for 10 to 15 min-utes? Test this question by placing the leaf in a glass of 5 percent N a C l solution. Remove after 15 minutes and observe under the micro-scope in a drop of the 5 percent NaC l solu-tion. • What are the results [7]? • How can you tell if the cell is dead [8]? • What have you observed in Parts A and B of this inquiry about cell membrane activity [9]? • Why do you think the membrane in one instance inhibits the passage of a substance and in another instance does not [10]? • W h a t conclusions can you draw regarding the sizes of molecules of Congo red and of water [11]? • On- the basis of your study of Part B, formulate a statement about the ability of a cell to maintain its internal stability in a chang-ing environment [12]. MITOSIS AND GENETIC CONTINUITY "L ike tends to beget like." This phrase has a meaning so self-evident, we hardly pause to give it a second thought. Oak trees give rise to oak trees; rabbits reproduce more rabbits. Somehow the reproductive cells of an oak or a rabbit receive —and pass.on —hereditary mate-rials that give them and their descendants specific characteristics of oaks or rabbits and not of some other organism. How have these hereditary potentialities been passed on from one cell to the next in such a precise way that all of. them, both in quantity and quality, can be transmitted to the reproductive cells? To answer, this question we must investigate the changes that occur in the nucleus of a cell before cell division occurs. These nuclear events are called mitosis. The process of mitosis is not easy to see in living cells because the nucleus and all the structures within it are nearly transparent in the living condition. We learned in Inquiry 1-4 about a special kind of microscope —the phase-contrast microscope —that makes it possible to see cell structure without killing cells, and that makes it possible to observe transparent structures. We could use such a microscope to observe mitosis in living cells. 52 - 79 -6 2 Photosynthesis EXERCISE 20 HOW DOES LIGHT INTENSITY AFFECT THE RATE OF PHOTOSYNTHESIS? The intensity of sunlight striking the surface of the Earth varies from hour to hour as well as from one season to another. Since oxygen is a by-product of photosynthesis, oxygen production may be used in designing an experiment to measure the effect of variations in light intensity on photosynthesis. The produc-tion of oxygen may be demonstrated by placing a plant under water and then measuring the escape of oxygen bubbles. In this exercise, changes in the photosynthetic rate under different light intensities will be measured. PROCEDURE Following the method shown in Fig. 5.2, calculate the aver-age number of bubbles produced per minute with the lamp 20 inches from the Elodea. 20-A Record your data in the table on page 279. Move the lamp to a distance of 10 inches from the Elodea. Allow the set-up to stand for five minutes. 20-B Why? Determine the average bubble count at this distance (10 inches) and record your data. Repeat this experiment with the light source five inches from the Elodea and record your data in the table. 20-C Graph your results on page 279. FOR T H O U G H T , D ISCUSSION, A N D FURTHER STUDY 1 How can you prove that the bubbles given off during photo-synthesis are composed of oxygen? 2 How has the intensity of the light been varied in the experi-ment conducted in this exercise? 3 What is the relationship between the amount of oxygen pro-duced (as bubbles) and light intensity? 4 If you were able to increase the intensity of light indefinitely, would you expect the production of oxygen to continue to increase at the same rate? Explain. - 30: " FIG. 5.2 PROCEDURE FOR DETERMINING THE EFFECT OF LIGHT INTENSITY ON PHOTOSYNTHESIS Select a "healthy look-ing" iprig of Elodea 6 Inches in length. Place it upside down In a large test tubo of spring water containing 0.25% sodium bicarbonate. Before com-pletely submerging the Elodea sprig, cut of f W Inch from the base of the stem with a sharp razor blade. Remove any leaves near the cut end. Place a short piece of rubber tubing over a 15-inch length of glass tubing. Suck up pond or spring water until the tube is full. Then hold your finger over rubber tubing so that the water column does not fall, and then clamp the rubber tubing. Position the glass tubing gently over the end of the Elodea sprig and then clamp lost tube and glass tube to a ring stand. Keep Elodea and glass tube below water level. C Position a light 20 Inches from the plant. Place a con-tainer of cool water between the light and the Elodea. (Why?) Turn the light on and allow to stand for S minutes before taking any readings. (Why?) D Count the bubbles pro-duced each minute for a 5 minute period. Calcu-late the average bubble count per minute. - 81 -64 Photosynthesis EXERCISE 21 HOW C A N YOU DETERMINE IP CARBON DIOXIDE IS NECESSARY FOR PHOTOSYM ("i-IESIS? The atmosphere is composed predominantly of nitrogen (approxi-mately 78 per cent) and oxygen (approximately 21 per cent). In addition, it contains variable amounts of water vapor and small quantities of other gases. Carbon dioxide ( C O 2 ) constitutes about 0.04 per cent by volume of the atmosphere. PROCEDURE Your instructor will provide .you with several geranium plants that have been kept in the dark for 36 to 48 hours. Select a leaf from one of the plants and test it for the presence of starch (Figs. 5 . 3 A . B ) . Return the plants to the dark during the time you are testing the leaves. 21-A Why? C A U T I O N : K O H or NaOH is ^ a strong, positive starch test occurs, select another plant oxiromtly hazardous t ° and-test the leaves until a negative or very weak starch test Do not touch with your occurs. 21-S Why is this step necessory? hands. Uio tongs or a plastic Set up the experiment as shown in Figs. 5 . 3 C . D . This is spoon to transfer this chem- a c c o m p l i s h e d b y p l a c i n g a geranium leaf in an atmosphere ital froin its contoincr. a lacking C O 2 . Potassium or sodium hydroxide ( K O H or NaOH) effectively remove C O 2 from the air. 21-C What "control" should be set up so that nteanir.gful conclusions can be made? Set up this "control" along with the experimental set-up and place the "control" under bright lights for 24 hours. Test for photosynthetic activity by testing the leaves for starch. FOR T H O U G H T , D ISCUSSION, A N D FURTHER STUDY 1 In Fig. 5 .3 , why is potassium hydroxide (or sodium hydroxide) placed within the jar as well as in the funnel? 2 Based on the results of the experiment, what conclusions can be made about the necessity of carbon dioxide for photo-synthesis? 3 Suppose you were to put a sprig of Elodea into a test tube completely filled with boiled (and cooled) water. You then seal the tube with a rubber stopper and place it under bright light. Would you expect photosynthesis to occur? Explain. 4 A solution of phenol red is orangish-red in the presence of carbon dioxide. The solution becomes yellowish in the absence of carbon dioxide. Devise an experiment to show that Elodea plants use C O 2 when photosynthesizing. - 82 -FIG. 5.3 PROCEDURE FOR DETERMINING IF CO, IS NECESSARY FOR PHOTOSYNTHESIS A Remove leof from trie plonl kept in the dark. Place leaf in hot olcoho! until pigment i« removed. C Place a leaf in atmosphere locking CO*. Of H.O EXPERIMENTAL SET UP Place "experimental" and "control" set ups under bright lights for 24 hours. Then test for starch as shown in steps A and B. 96 Biological Transport EXERCISE 31 • WHAT IS THE EFFECT OF VARIOUS ENVIRONMENTAL FACTORS ON TRANSPIRATION? Most land plants obtain water from the soil. However, only a small amount of the water absorbed by the roots is used in growth and photosynthesis. The rest is lost through transpira-tion, a process in which water is lost (as water vapor) from the surface of leaves, or i n some cases, from other aerial parts of plants. In this exercise you will use an apparatus called a potometer to determine the effects of various environmental factors on the rate of transpiration. PROCEDURE • Completely cover the potometer flask (except for the openings) with aluminum foil. • Using a 2-inch piece of rubber tubing, attach a 15-inch length of capillary tubing to the potometer flask. Support the capillary tubing in an elevated position, using a clamp and ring stand as shown in Fig. 8.1 A. Attach a millimeter ruler to the back of the tubing with tape. N O T E : TKe rubber tubing' • F i l l the flask to the brim with water provided by your must fit tightly on the capil- instructor. Pour the water i n slowly to avoid the formation lory luoing to prevent air of bubbles. lc'uK1"-- • Following the procedure shown in Figs. 8.1 B,C,D, cut a branch from a geranium plant and insert it into a rubber stopper. Keep the cut end moist, but avoid wetting the leaves. noi£: After cutting the • Slowly insert the rubber stopper and branch into the flask hror.cn oft, hold the cut c.id to avoid creating bubbles. (If this is done properly, water under . a running faucet w i l l be forced out of the end of the capillary tubing. When .(uvuid wetting tne leave^i) ^ pressure on the stopper is released, the fluid in the capil-he ! epi ^ a r v t u D m g wiM t e n d to move back toward the flask. If this v.t brecUinj \'.-.\.- should occur, f i l l a syringe with water and insert the needle of v/uier in tha vuo- into the rubber tubing at the place where the capillary tub-"*' 1 ' ing and the flask join. Slowly inject water until it comes back out of the end of the capillary tubing.) • Loosen the clamp on the ring stand and lower the capil-lary tubing so that it is level with the surface of your table or desk (Fig. 8. IE). If the apparatus has been properly set up, the water column in the tube will begin to recede toward the flask. 31 - A V/i.ai i i ri.--j[.'i-i'i lor'this, rvio vonionl of water? The rate at which the water moves is a measure of the rate of water uptake by the branch and may be used as a measure of the rate of transpiration. c.;:ci cut anoihc-r inch on. Th cui i-urfacci mu i o i U IVi f culur t i s i U t - s of the brunch - 84 -FIG. 8.1 PROCEDURE FOR DETERMINING THE RATE OF TRANSPIRATION C Hold branch under water and cut off about 2 cm of stem. Select a rubber stopper having a hole slightly smaller than diameter of stem. Insert a cork borer as shown, and ploce stem far enough Into cork borer so that when borer is removed the stem will project about 1 cm below the stopper. Carry out this procedure under water, but do not allow leaves to become wet. Rubber stopper Cork borer Lower tube so it is level with the surface when ready to take measurements. Hole slightly smaller thon stem If water column goes past the end of the ruler. It may be returned to starting point by injecting water into rubber tubing with syringe. - '85 -98 Biological Transport N O T E : If tlio water column Soes past the ind of the ruler nearest the flask, it may be returned to your starting po-sition by injecting water into the rubber tubiny connecting thu capillary tubing to the flask. • Determine the transpiration rate by recording the distance the water column moves each minute for a period of 10 min-utes (be prepared to change to shorter or longer intervals of time depending on the rate of water movement in the column). 31-B Record your results in the table on page 301. 31-C Graph your data on page 30_. FOR T H O U G H T , D ISCUSSION, A N D FURTHER STUDY 1 Under what conditions in nature would you expect a plant to have a high or low rate of transpiration? 2 D i d you have a "control" for this experiment? If not, suggest one. 3 How do you think a scientist would proceed to measure the actual force of the transpirational pull in this experiment? 4 How is the movement of water and dissolved substances in a plant related to transpiration? 5 In this experiment, what parts of the apparatus represented the missing (cut off) parts of the whole plant? 6 In order for plants growing in a desert to survive, what are some of the adaptations of the leaves or other organs that you would expect to find? 7 If you used the procedure in this experiment, what would be the effect of the following on the rate of transpiration—light intensity, air movement, humidity, others? Enter your results in the table on page 301 and graph your data in Fig. 31-C. 8 Devise a method for estimating the volume of water lost in transpiration per unit area of leaf surface in a given time (using the apparatus of this experiment). 9 Of what value is this control of water loss to the plant? EXERCISE 49 HOW DO GIBBERELLINS AFFECT PLANT GROWTH? Gibberellins are plant growth substances that were first isolated in Japan from a fungus that caused a disease called "foolish seedling disease." The Japanese scientists who studied this disease found that the fungus was producing chemical sub-stances that were strongly affecting the normal growth and development of rice plants. Gibberellins are also produced by the higher plants, beans, for example. In this exercise you will attempt to determine what aspect of plant growth is affected by this plant growth substance. PROCEDURE • Working in teams of three, obtain 40 bean seeds that have been soaking in water for several hours. • Plant 20 seeds (about Vi inch deep) in moist vermiculite in a tray. Label the tray "Gibberellin treated" (Fig. 11.4B). • Plant the remaining 20 seeds in a second tray labeled "Control" "(Fig. 11.4B). • Watch the trays for the next seven to 10 days. When the plants are several centimeters tall (about three inches), select 10 plants in each tray that are about the same size. Label each individual plant with a number (1, 2, 3,...) along with the date. Cut the remaining plants at the ground level and discard the parts you have cut off (Fig. 11,4C). • Measure the height of each plant (in millimeters) from the soil to the tip of the shoot apex. 49-A Record the individual measurements in the table (page 341) under thu column headed "Day 0." • Apply a drop of gibberellin to the shoot apex of each plant in the " G - A " tray (Fig. 11.4D). 49-B What will you apply to the "control" plants? (This procedure should be repeated in three to four dc:ys.) • Measure the height of each plant in the "experimental" and "control!' groups on each of five days following the initial measurement (Day 0) and on the eighth day (Fig. .11.4E). Record the measurements in the table (49-A). 49-C Do the conhol plants respond to gibberellin in the same wuy as the experimental plants? If not, how do they differ? • Using the data in the table (49-A), calculate the per cent increase in length for each group on the first, second, third, fourth, fifth, and eighth day by using the following formula: - 87 -FIG. 11.4 PROCEDURE FOR DETERMINING EFFECT OF GIBBERELLIN ON PLANT GROWTH A Select 40 seeds that have been soaking for several hourj. B Plant 20 seeds In Vermicullte and label "Gibberellin treated experiment." Plant remaining 20 seeds and label "control." C After 7-10 days, select 10 plonb that are about the same size. Tag them with a number (1 A 3 , etc) and the dale. Discard remaining 10 plants. D Apply a drop of Gibber-ellin solution to shoot apex. Measure this distance. Measure each plant (In millimeters) in the experimental and control groups. Record your measurement! In the table on page 341. - 89 -156 Plant Development Average length (day 1, 2, 3, etc.) — Average Initial Length Average Initial Length X 100 = % Increase in Length Plot these data in 49-D. Use a different colored pencil for the experimental and control group. F O R T H O U G H T , D ISCUSSION, A N D FURTHER STUDY 1 Based on the results of this experiment, what do you think the rice plants that have "foolish seedling disease" look like? 2 The peas used in this exercise are a dwarf variety whose dwarfness is controlled by a single gene. Suggest a possible way this gene might produce dwarf plants. 3 How would you go about determining where gibberellins are produced i n the plant? >. 11.5 EFFECT OF GROWTH INHIBITORS ON PLANT DEVELOPMENT Examine the planti every 2 to 3 days for the next 3 weeks. Record your observations in the table (on page 343) and by a drawing (on page 344), - 89 -APPENDIX D An Example of the Process S c i e n t i f i c Investigation - 90 -AUTHOR'S MODEL OF THE PROCESS OF SCIENTIFIC INVESTIGATION Problem Observations under Natural Conditions Hypothesis Prediction Literature Research New Observations, New Hypothoses Support of Questionning of Hypothesis Observations and/or Experimentation under Controlled Conditions Design of Experiment New Problems - as used in preliminary lesson (P) of experimental group AN EXAMPLE OF THE APPLICATION OF THE SCIENTIFIC METHOD PROBLEM What internal factor causes the male piranah's b e l l y to turn bright red in the presence of an estrus female piranah? OBSERVATIONS (1) When an estrus female piranah is placed near a male piranah, the piranah's belly turns red. (2) If the female is not in estrus then the male b e l l y does not turn red. ( A l l other conditions controlled) RESEARCH (1) When an estrus female of almost any higher vertibrate comes near the male of the species, the levels of testosterone in the blood stream of the male r i s e s . (2) From experiment, i t has been shown that the levels of testosterone in the blood stream of the male piranah r i s e when an estrus female is present. HYPOTHESIS Perhaps testosterone is the internal factor responsible for the red be l l y of the male piranah. EXPERIMENTAL PROCEDURES AND DATA COLLECTION (1) Castrate a male, put with female - red belly? (Tabulate several t r i a l s . ) Answer - not. Control - non-castrated male under the same condition. (2) Inject a castrated male with testosterone, place with estrus female - red? (Tabulate several t r i a l s . ) Control - castrated male. Answer - yes. - 92 -ANALYSIS Any graphs accumulated from data. DISCUSSION Problems with the p r a c t i c a l aspects of the experiment. Any unexpected ( i . e . , off the topic) results? Sources of error? CONCLUSION The testosterone seems to produce the red b e l l y . Additional examination required, e.g., h i s t o l o g i c a l data, metabolic date. Maybe testosterone is a precursor for something else. - 93 -APPENDIX E A c t i v i t i e s in the Experimental Group's Investigative-based Laboratory Program - 94 -CATALASE ACTIVITY OF VARIOUS TISSUES - LAB 1 PRIOR KNOWLEDGE 1. H 2 0 2 CATALASE H 2 + 1/2 0 2 + Energy (ENZYME) PEROXIDE (A METABOLIC POISON) 2. Catalase is found in l i v i n g tissues in various concentrations depending on the amount of peroxide present. 3. Peroxide is sometimes used as an anti s e p t i c . 4. 1 cal o r i e is the amount of heat required to raise the temperature of 1 gram of water 1°C. 5. A calorimeter is a device used to measure the amount of heat released or used by a reaction. STATEMENT OF THE PROBLEM What are the r e l a t i v e amounts of catalase found in various kinds of tissue? HYPOTHESIS (THEORY) Make a statement with regard to the following tissues -cooked and uncooked minced - apple, potato, kidney and l i v e r . Substantiate your statements. - 95 -D. EXPERIMENTAL PROCEDURES Be sure your procedures are well organized such that the experiment may be repeated by another investigator. The design must include controls*, the number of t r i a l s to be run, the length of each t r i a l , etc. Some equipment w i l l be l a i d out for you - ask for anything in addition that you think you might need. E. DATA Gather and tabulate data - be sure data tables depict quantitative results (numbers, symbols). Organize your observations. F. ANALYSIS To adequately analyze data, figures may be graphed so as to see trends. G. DISCUSSION What relationships may be seen between the analysis of the data and the o r i g i n a l hypothesis? Use your i n t u i t i o n , imagination and reasoning to interpret and speculate from your analysis of data. Any sources of error? * " I t has been conclusively demonstrated by hundreds of experimentors that the beating of drums w i l l restore the sun aft e r an e c l i p s e " . S i r R.A. Gregory - 96 -H. CONCLUSIONS What conclusions ( i f any) can be made about the o r i g i n a l hypothesis? What further problems are suggested by the outcomes of the research? FINAL WRITE-UP 1. T i t l e 2. Statement of the problem 3. Formulation of the hypothesis 4 . Experimental procedures 5. Collection of data 6. Analysis of data 7. Discussion 8. Conclusion. - 97 -C a t a l a s e A c t i v i t y - Teacher's Notes - LAB Mf A) A p p a r a t u s s u p p l i e d - cooked and uncooked, minced p o t a t o e and l i v e r (20$ s o l u t i o n ) - l o n g TT', thermometers, s t o p p e r s ( i e . crude c a l o r i m e t e r s ) - 3 $ p e r o x i d e s o l u t i o n g r a d u a t e d c y l i n d e r s , b a l a n c e s - t w e e z e r s , t u b i n g , v o l u m e t r i c t u b e s , r i n g s t a n d s . B) H y p o t h e s i s - be; sure : to) watch t h a t s t u d e n t s comment on b o t h t h e r e l a t i v e amounts o f c a t a l a s e i n cooked vs uncooked m a t e r i a l and l i v e r v s p o t a t o e . J u s t i f i c a t i o n must be p r o v i d e d f o r h y p o t h e s i s based on p r i o r knowledge. C) E x p e r i m e n t a l P r o c e d u r e s - any p r o c e d u r e s t h a t attempt t o measure th e amount o f e i t h e r oxygen o r energy r e l e a s e d from t h e breakdown' o f p e r o x i d e i s s a t i s f a c t o r y . B e f o r e a c t u a l e x p e r i m e n t a t i o n b e g i n s s t u d e n t s w i l l have t o e s t a b l i s h t h e amount o f t i s s u e t o be u s e d - too* much w i l l r e s u l t i n e x c e s s -i v e oxygen. D) Data and A n a l y s i s - s t u d e n t s w i l l h o p e f u l l y c a t e g o r i z e t h e i r d a t a i n a r e a d a b l e f a s h i o n . A g r a p h i c a l a n a l y s i s o f temp, v s t i m e c l a r i f i e s d a t a i f t h e energy component i s measured. E) D i s c u s s i o n - f u l l and complete d i s c u s s i o n o f a l l e x p e r -i m e n t a l r e s u l t s are l o o k e d f o r i n c l u d i n g any s o u r c e s o f e r r o r t h a t may have a f f e c t e d t h e r e s u l t s - eg. p o o r l y i n s u l a t e d c a l o r -i m e t e r , p r e s s u r e b u i l d up) i n t h e s t o p p e r e d t e s t - t u b e . - 98 -L a b o r a t o r y 2  R e a c t i o n o f C e l l s i n Changing Environments A) P r i o r Knowledge 1) The c l o s e l y r e g u l a t e d environment i n s i d e an e l o d e a c e l l c o n t a i n s a c o n c e n t r a t i o n o f approx. 0.9$ N a C l . 2) The n a t u r a l environment o f e l o d e a i s pond w a t e r of approx. 100$ B"20. 3) Reveiw a l l o f t h e t h e o r e t i c a l p r i n c i p l e s o f osmosis and d i f f u s i o n b e f o r e c o n t i n u i n g . B') Statement o f t h e Problem What i s t h e response; o f an e l o d e a l e a f c e l l t o an environment t h a t c o n t a i n s a h i g h e r c o n c e n t r a t i o n o f NaCl t h a n i t s n a t u r a l environment? C) Hypothesis. D) E x p e r i m e n t a l P r o c e d u r e s E) Data and O b s e r v a t i o n s F) A n a l y s i s G) D i s c u s s i o n - f o l l o w g e n e r a l g u i d e l i n e s from p r e v i o u s l a b . - 99 -R e a c t i o n o f C e l l s i n Changing E n v i r o n m e n t s - LA6 %  Teacher's No>tes A) A p p a r a t u s s u p p l i e d - s p r i g s o f e l o d e a - % F a C l s o l u t i o n - m i c r o s c o p e s l i d e s and c o v e r s l i p e s - eye d r o p p e r s B) H y p o t h e s i s - be s u r e t h e r e a s o n s f o r t h e h y p o t h e s i s a r e c l e a r l y s t a t e d and s u p p o r t a b l e by t h e o r e t i c a l n o t i o n s . C) E x p e r i m e n t a l P r o c e d u r e s - adequate c o n t r o l o f p r o c e d u r e s i s most n e c e s s a r y - l i g h t , t e m p e r a t u r e and w a t e r c o n t e n t a r e c r i t i c a l . I t i s b e t t e r to> use t h e same l e a f c e l l as c o n t r o l (100$ water') and e x p e r i m e n t a l (5% w a t e r ) - t h i s w i l l a l l o w s t u d e n t t o v i e w t h e e v i d e n c e c o n t i n u o u s l y . D) Data and A n a l y s i s : - be s u r e t h a t o n l y measured v a l u e s a r e r e c o r d e d on t h e d a t a t a b l e - a l l q u a l i t a t i v e r e s u l t s a r e o b s e r v a t i o n s and s h o u l d be i n c l u d e d under t h a t t i t l e . D i s c u s s i o n - t h e major s o u r c e s o f e r r o r a r e -maintenance o f c o n t r o l l e d c o n d i t i o n s , i m p r o p e r and i n a d e q u a t e e v i d e n c e f o r s t a t i n g a s s u r e d e l y t h a t t h e environments a r e as c l a i m e d . - 100 -L a b o r a t o r y 3  L i g h t , I n t e n s i t y and t h e Rate o f P h o t o s y n t h e s i s A) P r i o r Knowledge 1) L i g h t i n t e n s i t y v a r i e s from hour t o hour as w e l l as season to: season on t h e e a r t h . 2) L i g h t i n t e n s i t y i s a measure o f the q u a n t i t y o f l i g h t and may t h e r e f o r e be measured i n w a t t s . 3) The r a t e o f p h o t o s y n t h e s i s r e f e r s t o t h e amount o f p h o t o s y n t h e t i c a c t i v i t y t a k i n g p l a c e i n t h e p l a n t l e a f o v e r t i m e . 4) E l o d e a , a w a t e r pikant, w i l l be u sed as t h e e x p e r i -mental subject.. F o r i n f o r m a t i o n c o n c e r n i n g e l o d e a and i t s n a t u r a l environment, see l a b 2. B) Statement o f t h e Problem How does l i g h t i n t e n s i t y a f f e c t t h e r a t e o f p h o t o -s y n t h e s i s i n e l o d e a l e a f c e l l s ? C) H y p o t h e s i s D) E x p e r i m e n t a l P r o c e d u r e s E) Data and O b s e r v a t i o n s P) A n a l y s i s - f o l l o w g e n e r a l guidelin§s G-) D i s c u s s i o n from p r e v i o u s l a b s . - 101 -L i g h t I n t e n s i t y and t h e Rate o f P h o t o s y n t h e s i s - L a b 3 Teacher's Notes A) A p p a r a t u s s u p p l i e d - s p r i g s * of e l o d e a - t e s t t u b e s , c l a m p s , r i n g stands-- v a r i o u s wantages o f l i g h t b u l b s - pond w a t e r B) H y p o t h e s i s - most s t u d e n t s w i l l make a g e n e r a l statement c o n c e r n i n g l i g h t i n t e n s i t y and t h e r a t e o f p h o t o -s y n t h e s i s . I n d e e d , l e c t u r e knowledge up "to t h i s p o i n t i s i n s u f f i c i e n t t©> w a r r a n t any d e t a i l e d h y p o t h e s i s such 100 watt i n c r e a s e w i l l r e s u l t i n a t w o - f o l d i n c r e a s e i n p h o t o s y n t h e t i c a c t i v i t y . A more g e n e r a l h y p o t h e s i s such a s ; as t h e i n t e n s i t y i n c r e a s e s one w i l l f i n d t h a t p h o t o s y n t h e t i c a c t i v i t y w i l l a l s o i n c r e a s e ; i s s u f f i c i e n t . C) E x p e r i m e n t a l P r o c e d u r e s - some s t u d e n t s w i l l attempt t o use the amount o f sugar produced by p h o t o s y n -t h e s i s as an i n d i c a t i o n o f p h o t o s y n t h e t i c r a t e . T h i s i s d i f f i c u l t to:: measure over t i m e . More ad-equate i s measure o f oxygen e m i s s i o n w h i c h may be r e a d i l y d e termined by c o u n t i n g b u b b l e s emerging from t h e e l o d e a l e a v e s . D) Data and A n a l y s i s - i t i s i m p o r t a n t f o r the s t u d e n t t o u n d e r s t a n d t h a t t o measure th e RATE o f photoi-s y n t h e t i c a c i t i v i t y , one must measure t h e amount of p h o t o s y n t h e t i c p r o d u c t produced o v e r t i m e . E) D i s c u s s i o n - f o r t h e d i s c u s s i o n to be adequate, a c l e a r r e l a t i o n s h i p must be p r e s e n t e d from d a t a a n a l y s i s . Some s t u d e n t s may not have used enough t i m e t o e s t a b l i s h t h e l e v e l l i n g o f f i n p h o t o s y n t h e t i c a c t i v i t y t h a t s h o u l d ^ o c c u r r e d a f t e r c o n t i n u o u s i n t e n s i t y exposure:. - 102 -L a b o r a t o r y 4 V a r y i n g Q u a n t i t i e s o f Carbon D i o x i d e Exposure and P h o t o -s y n t h e t i c A c t i v i t y . A) P r i o r Knowledge 1) I n t h i s case t h e amount o f exposure o f a p l a n t t o v a r y i n g q u a n t i t i e s o f carbon d i o x i d e a r e r e l a t e d to t h e r a t e o f p h o t o s y n t h e s i s . 2) A l t h o u g h t h e atmosphere i s j p r e d o m i n a t e l y composed o f n i t r o g e n ( a p p r o x i m a t e l y 78%); and oxygen ( a p p r o x i m a t e l y 21$); c a r b o n d i o x i d e c o n s t i t u t e s about 0.04 p e r cent by volume o f t h e atmosphere. 3) Q u a n t i t i e s o f carbon d i o x i d e do v a r y g l o b a l l y . H i g h e r c o n c e n t r a t i o n s are found i n i n d u s t r i a l i z e d a r e a s where t h e b i - p r o d u c t s o f f o s s i l f u e l com-b u s t i o n a r e e m i t t e d i n t o t h e - a i r . 4) P o t a s s i u m o r sodium h y d r o x i d e s o l i d s w i l l e f f e c t -i v e l y remove C02 from the: a i r . B5) Statement o f t h e Problem What i s t h e r e l a t i o n s h i p between photo<synthetic a c t i v i t y i n a geranium l e a f and v a r y i n g q u a n t i t i e s o f carbon d i o x i d e exposure t o t h a t l e a f ? - 103 -V a r y i n g Q u a n t i t i e s o f Carbon D i o x i d e Exposure and P h o t o - s y n t h e t i c A c t i v i t y - Lab 4 Teacher's Notes A) A p p a r a t u s S u p p l i e d - Geranium p l a n t s ; - B e a k e r s , p e t r i d i s h e s , f u n n e l s - KOH, NaOH s o l i d s - lamps, c o t t o n , hot p l a t e s - a l c o h o l , i o d i n e s o l u t i o n B-) H y p o t h e s i s — most s t u d e n t s w i l l suggest a d i r e c t v a r i a t i o n r e l a t i o n s h i p between the amount o f CO2 and p h o t o -s y n t h e t i c a c t i v i t y . However, a more r e f i n e d and d e f i n i t i v e statement may be f o r w a r d e d as a r e s u l t o f t h e e x p e r i e n c e g a i n e d from t h e l a s t l a b where p h o t o s y n t h e s i s r a t e s were measured. C) E x p e r i m e n t a l P r o c e d u r e s - t h i s time a geranium p l a n t i s p r o v i d e d , not e l o d e a . Because geraniums a r e not h y d r o p h y t e s as a r e e l o d e a p l a n t s , oxygen e m i s s i o n i s hot as v i a b l e a measure of photo>synthetic a c t i v i t y . The: a l c o h o l b a t h method o f e x t r a c t i n g c h l o r o p h y l l may be demonstrated i f d e s i r e d . I o d i n e may t h e n be u sed t o i n d i c a t e the presence o f s t a r c h . D) Data and A n a l y s i s - accumulated d a t a s h o u l d n a t u r a l l y l e a d to» a g r a p h i c a l and p o s s i b l y m a t h e m a t i c a l c o r r e l a t i o n between p h o t o s y n t h e t i c a c t i v i t y and c a r b o n d i o x i d e c o n c e n t r a t i o n . E) D i s c u s s i o n - c o n t r o l l i n g such v a r i a b l e f a c t o r s as t h e q u a l i t y and q u a n t i t y o f l i g h t , q u a n t i t y o f w a t e r and t h e s o i l c o m p o s i t i o n must be f u l l y d i s c u s s e d . - 104 -Laboratory 5 - Determination of the Quantity of G i b b e r l l i c Acid in a Bean Seedling A) Prior Knowledge 1) G i b b e r l l i c acid is a plant growth hormone that causes stem elongation in bean seedlings. 2) The quantity of g i b b e r l l i c acid in most dicotyledonous plants is extremely small. (<0.01 g/plant) 3) A g i b b e r l l i c solution, using water as the solvent, is often applied to the apical meristematic region by h o r t i c u l t u r a l i s t s when c e l l elongation is required in the stem. B) Statement of the Problem What is the precise quantity of g i b b e r l l i c acid in the plant body of the common castor bean (Ricinus communis)? - 105 -Determination of the Quantity of G i b b e r l l i c Acid In a Bean Seedling - Lab 5 - Teacher's notes A) Apparatus supplied - 200 pre-soaked castor bean seeds - plant trays - vermiculite, potting s o i l - labels, eye droppers, toothpicks - solutions of g i b b e r l l i c acid (0.0001 g, 0.0005 g, 0.001 g, 0.005 g, 0.01 g in 10 ml water) B) Hypothesis - a s p e c i f i c statement is requested here yet students r e a l l y do not have s u f f i c i e n t experience to stipulate anything but a general range. A l i t t l e research concerning g i b b e r l l i c concentrations and dicotyledon plants should bring a figure of within 0.0005 and 0.01 g per 10 ml water. C) Experimental Procedure - using known concentrations of g i b b e r l l i c acid the student should design a controlled experiment using several plants exposed to the hormone concentrations. The quantity of g i b b e r l l i c acid is estimated by comparison to the a b i l i t y of known concentrations of the hormone to stimulate stem elongation. D) Data and Analysis - data must include the control measure of plant stem growth (p.O g of g i b b e r l l i c acid) and stem growth of a l l other plants. A l l plants i n i t i a l l y are the same size so as to allow comparisons after f i n a l growth, (termination - 8 days) Analysis of height (y-axis) and hormone concentratin (x-axis) should result in a li n e a r relationship y=mx+b. The slop of the - 106 -growth (m) depicts the rate of growth. Calculating for a y equal to the average height of the control plants, a comparison may be made to the experimental plants which were under varying conentrations of g i b b e r l l i c acid. E) Discussion - due to the fact that such minute concentrations of hormone are used i t i s c r i t i c a l that solutions are made up car e f u l . The degree of error should be indicated as potential sources of error. Stem elongation may be discussed with p a r t i c u l a r reference to apical meristem histology. - 107 -Laboratory 6 - The Rate of Transporation and Humidity A) Prior Knowledge 1) As s t r i c t l y defined, transporation refers to the process whereby water vapor is lost to the atmosphere from plant leaves. 2) For the purposes of this lab, the amount of water absorbed by the roots that is used in growth and photosynthesis is i n s i g n i f i c a n t compared to the amount of water that is absorbed and then lost through transpiration. 3) Cobalt chloride paper (supplied) is sensitive to moisture. In the presence of moisture, this blue paper turns pink. 4) Relative humidity is a measure of the quantity of moisture in the a i r compared to the same a i r when saturated. Relative humidity is measured as a %, i e . 100% is saturation; 60% would mean the a i r i s 60% saturated with moisture. Humidity is measured using a s l i n g paychrometer. B) Statement of the Problem How does a change in r e l a t i v e humidity affet the rate of transpiration from a geranium plant? - 108 -The Rate of Transpiration and Humidity Lab 6 - Teacher's Notes A) Apparatus Supplied - Geranium plants - Ring stands, clamps - glass tubing (2mm diameter) - rubber tubing - razor blade - 100 and 250 ml beakers B) Hypothesis - saturated a i r (R.H.=100%) provides reverse pressure on leaf transpiration in view of the fact that saturated a i r can no longer hold water that is bein g transpired. Most students w i l l use this as an indication that dryer a i r w i l l allow for more rapid transpiration and that saturated a i r w i l l reduce the transpiration rate close to zero. C) Experimental Procedure - two d i f f i c u l t i e s w i l l emerge when students set out to design their procedure -1) How to control r e l a t i v e , ambient humidity. 2) How is measure the rate of transpiration. This f i r s t problem may be overcome by taking measurements over a period of several days, as R.H. varies considerably from day to day depending on meteorological conditions. The second problem w i l l be solved in a variety of ways the best of which incorporate the use of an instrument that measures the uptake of water by the plant's roots as an indication of transpiration rate. - 109 -Data and Analysis - graphical analyses readily indicate the relationship between humidity and rate of transpiration. As humidity is the independent variable i t is displayed on the x-axis. Discussion - cont r o l l i n g variables is d i f f i c u l t in this experiment, p a r t i c u l a r l y i f the procedures take several days for completion. Temperature must be controlled as must quality, quantity and duration of l i g h t . Many students w i l l make mention of the many and varied p r a c t i c a l problems with their apparatus. - 110 -Laboratory 7 - The Rate of Transpiration and Temperature A) Prior Knowledge 1) This is a continuation of the previous lab in the sense that you w i l l be measuring the rate of transpiration again. 2) In this case you w i l l relate ambient temperature to the rate of transpiration. Temperature is measured in °C and w i l l be measured using a standard laboratory thermometer - + 0.02°C. (degree of error) 3) In view of the discrepancies obtained using your previous apparatus, this lab provides an opportunity to 'upgrade' your technique, therby increasing your experimental v a l i d i t y . B) Statement of the Problem How does a change in ambient temperature affect the rate of transpiration from a geranium plant? - I l l -The Rate of Transpiration and Temperature - Lab 7 The same apparatus is supplied for this lab us that for the l a s t lab as this experiment is e s s e n t i a l l y a continuation of lab 6. It is hoped that by continuing an investigation of the same phenomena (that of transpiration) that tudents w i l l learn from past errors and use either a modification of previous technique or a wholly new technique depending on degree of previous error. The variable factor of temperature is more e a s i l y varied than humidity so the students should find that obtaining results occurs in a shorter period of time. By using p r i o r experience from a previous piece of work (lab 6) i t is hoped that students w i l l not only work faster but increase the v a l i d i t y of their r e s u l t s . - 112 -APPENDIX F Raw Scores for T, and T - 113 -SPI RAW SCORES - PRE TEST BLOCK B - CONTROL Student Number Score (x) x=x-x X2 1 110 1.86 3.46 2 121 12.86 165.38 3 111 2.86 8.18 4 112 3.86 14 .9 5 99 9.14 83.54 6 103 5.14 26 .42 7 117 8 .86 78.5 Female 8 125 16.86 284 .26 9 95 13.14 172.66 10 108 0.14 0.02 11 104 4.14 17.14 12 92 16.14 260 .5 13 129 20.86 435.14 14 110 1.86 3.46 15 130 21.86 477 .86 Male 16 96 12.14 147.38 17 112 3 .86 14.9 18 111 2.86 8.18 19 101 7 .14 51.0 20 80 28 .14 791.9 21 105 3 .14 9.9 21 )2270.98 21 )3054. 68 6 = 108.14 Z x 2 = 145 .46 x = ^ 145.46 = 12.06 (Mean) 6 = 108.14 (Std. Dev. )x = 12 .06 Range = 80 - 130 - 114 -SPI RAW SCORES - POST TEST BLOCK B - CONTROL Student Number Score (x) x=x-x X2 1 111 2.67 7.13 2 121 12 .67 160 .53 3 110 1.67 2.79 4 100 8.33 69.39 5 109 0 .33 0.11 Female 6 105 3.33 11.09 7 117 8.67 75.17 8 126 17.67 312 .23 9 94 14.33 205.35 10 109 0.67 0.45 11 109 0.67 0.45 12 93 15.33 235.01 13 123 14 .67 215.21 14 111 2.67 7.13 15 128 19 .67 386 .91 16 97 11.33 128.37 17 113 4 .67 21.81 Male 18 110 1.67 2.79 19 103 5.33 28.41 20 82 26 .33 693.27 21 104 4 .33 18 .75 21 )2275 21 )2662. 54 6 = 108.33 £ x 2 = 126 .79 x = 4126 .79 = 11.26 (Mean) 6 = 108 .33 (Std. Dev.)sr= 11.26 Range = 82 - 128 - 115 -SPI RAW SCORES - PRE TEST BLOCK C - EXPERIMENTAL Student Number Score (x) x=x-x X 2 1 97 10.5 110.25 2 110 2.5 6.25 3 123 15.5 240.25 4 83 24.5 600.25 Female 5 134 26.5 702.25 6 93 14 .5 210.25 7 125 17.5 306.25 8 95 12.5 156.25 9 104 3.5 12.25 10 103 4.5 20 .25 11 125 17.5 306.25 12 108 0.5 0.25 13 82 25.5 650.25 14 103 4.5 20 .25 15 120 12.5 156.25 Male 16 100 7.5 56 .25 17 114 6.5 42.25 18 125 16 .5 272.25 19 100 7.5 56.25 20 108 0.5 0.25 20 )2150 20 )3925.0 6 = 107.5 E x 2 = 196.25 x = n)l96 .25 = 14 .01 (Mean) 6 = 107.5 (Std. Dev. )x = 14 .01 Range = 82 - 134 - 116 -SPI RAW SCORES - POST TEST BLOCK C - EXPERIMENTAL Student Number 1 2 3 4 Female 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Male Score (x) 105 115 123 89 135 99 127 101 109 107 110 114 86 106 123 109 113 128 106 113 x=x-x 5.45 4.55 12.555 21.45 24 .55 11.45 16 .55 9.45 1. 3, 45 45 0.45 3.55 24 .45 4.45 12 .55 1.45 2.55 17 .55 4 .45 2.55 29.7 20 .7 157.5 460.1 602 131 273 89 2 11 0 12 597.8 19.8 157.5 2.1 6.5 308 .0 19.8 6.5 20 ) 2209 6 = 110.45 (Mean) 6 = 110.45 (Std. Dev.)x= 12.06 Range = 86 - 135 •Ex 2 = 145.49 20 ) 2909.8  .49 x = /\)145 .49 = 12 RAW SCORES -- 117 -EXPERIMENTAL GROUP (BLOCK C) y (post score) Student Number x (pre score) 1 97 105 2 110 115 3 123 123 4 83 89 5 134 135 Female 6 93 99 7 125 127 8 95 101 9 104 109 10 103 107 11 125 110 12 108 114 13 82 86 14 103 106 15 120 123 Male 16 100 109 17 114 113 18 124 128 19 100 106 20 108 113 TABLE Tn RAW SCORES -- 118 -EXPERIMENTAL GROUP (BLOCK C) y (post score) Student Number x (pre score) 1 110 111 2 121 121 3 111 110 4 112 100 5 99 109 Female 6 103 105 7 117 117 8 125 126 9 95 94 10 108 109 11 104 109 12 92 93 13 129 123 14 110 111 15 130 128 16 96 97 17 112 113 Male 18 111 110 19 101 103 20 80 82 21 105 104 TABLE T? - 119 -APPENDIX G S t a n d a r d D e v i a t i o n G r a p h s f o r T]_ and T2 - 121 -- 123 -- 124 -APPENDIX H Data Outlay for the Analysis of Covariance - 125 -Table 6 - Data Outlay -Student Number Y Xl X 2 X 3 1 105 1 97 97 2 115 1 110 110 3 123 1 123 123 4 89 1 83 83 5 135 1 134 134 6 99 1 93 93 7 127 1 125 125 8 101 1 95 95 9 109 1 104 104 10 107 1 103 103 11 110 1 125 125 12 114 1 108 108 13 86 1 82 82 14 106 1 103 103 15 123 1 120 120 16 109 1 100 100 17 113 1 114 114 18 128 1 124 124 19 106 1 100 100 20 113 1 108 108 - 126 -Table 7 - Data Outlay - T 2 Student Number Y 1 111 2 121 3 110 4 100 5 109 6 105 7 117 8 126 9 94 10 109 11 109 12 93 13 123 14 111 15 128 16 97 17 113 18 110 19 103 20 82 21 104 *1 x 2 X3 -1 110 -110 -1 121 -121 -1 111 -111 -1 112 -112 -1 99 - 99 -1 103 -103 -1 117 -117 -1 125 -125 -1 95 - 95 108 108 -1 104 -104 -1 92 - 92 -1 129 -129 -1 110 -110 -1 130 -130 -1 96 - 96 -1 112 -112 -1 111 -111 -1 101 -101 -1 80 - 80 -1 105 -105 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0055316/manifest

Comment

Related Items