Undergraduate Students’ Laboratory Practice Illuminated by The Philosophy of Science TheoryVs. Experimental Evidence. Rachel Havdala Guy Ashkenazi Dept. of Science Teaching, The Hebrew University of Jerusalem

Motivation Science students show great difficulties in coordinating their lab results with the theory they learned in class Aim To find ways to enhance the coordination between theory and experimental evidence Method Interviews - students views about the nature of science Lab reports analysis Question Is there any correlation between the students’ views about NOS and their lab practice?

Personal Epistemology A continuum in the perception of knowledge Observation or Reasonability Assessment and Integration External,Objective Constructed,Subjective Source of Knowledge Justification for knowing (Hoffer, 2004)

The main components of knowledge in science Experiment Theory

Empiricism: Empiricism: Emphasis on the primacy of objective sense experience. Emphasis on the primacy of objective sense experience. Experiment is justified by consensus of observation. Theory is justified to the extent it fits observation. Experiment is justified by consensus of observation. Theory is justified to the extent it fits observation. Rationalism: Rationalism: Confidence in the mind’s ability to formulate the orderly character of the world as objective laws of nature. Confidence in the mind’s ability to formulate the orderly character of the world as objective laws of nature. Theory is justified by reason and logic. Experiment is justified to the extent it is explained by theory. Theory is justified by reason and logic. Experiment is justified to the extent it is explained by theory. Theory vs. Experiment in the Philosophy of Science Theory Experiment Theory Experiment

Source of knowledge Knowledge is constructed by the individual to make sense of the subjective experiential world. Knowledge is constructed by the individual to make sense of the subjective experiential world. Justification for knowing Justification by “viability” – Coherence between perception and conception (experiment and theory). Justification by “viability” – Coherence between perception and conception (experiment and theory). Theory vs. Experiment in the Philosophy of Science Constructivism:

Primary Analysis of lab reports (General chemistry lab for chemists, consists of 8 lab sessions). Primary Analysis of lab reports (General chemistry lab for chemists, consists of 8 lab sessions). Choosing students for interviews Choosing students for interviews (12 from 2004, 13 from total). Primary analysis of interviews. Primary analysis of interviews. Selection of three students : Selection of three students : –Very decisive and consistent views about science. –Greatest disparity. –Belonged to the same lab group (from the class of 2004). The Analytical Process Primary analysis

Results : Views about NOS The dimensions, which showed to be of greatest contradiction between the three students: The dimensions, which showed to be of greatest contradiction between the three students: 1) 1)The basic component of knowledge in science. 2) 2)The purpose of scientific work. 3) 3)Main characteristics of science. 4) 4)The role of mathematics in science. 5) 5)Science in the students’ laboratory.

Views about NOS Q: How would you define a scientific law? A: It is something experimental, for sure… Q: What is it based upon? A: Only on experiment. […] First you need the experiment and then it will be accurate. […] As long as it is proved by an experiment, it is good. The basic component of knowledge in science The basic component of knowledge in science (Daphne)

Views about NOS Q: How does a scientist tries to think? Does he rely on assumptions or on facts? Q: How does a scientist tries to think? Does he rely on assumptions or on facts? A: I believe he has to rely on assumptions. You cannot know how a substance will behave in advance. You need to take some assumptions and try to make facts out of them. The basic component of knowledge in science The basic component of knowledge in science (Ted)

Views about NOS You cannot generalize. Every law has its own history. If someone got hit by an apple on his head… Sometimes the theory comes first, sometimes the experiment. It's a combination, always a combination. You cannot generalize. Every law has its own history. If someone got hit by an apple on his head… Sometimes the theory comes first, sometimes the experiment. It's a combination, always a combination. The basic component of knowledge in science The basic component of knowledge in science (Robert )

“Even those natural laws that we don’t know behave mathematically. This is what I believe.” Personal Philosophy Source of Knowledge Source of Knowledge “If I didn’t know that these results are already known, would it matter to me? It doesn’t matter – for me it is new… it is my own private research. For me that is sufficient.” “A scientific law… is generally discovered by chance, and then you do experiments to verify it.” Robert Ted Daphne

“Mathematics helps base certain theories, or invent new ones – you just see that a certain equation fits a certain experiment.” Personal Philosophy Justification of knowledge Justification of knowledge “It is true for now. What was written 200 years ago was true 200 years ago… When they tell you the law, it works… If you don’t have a problem, you will take it for granted.” “You need it to be objective, not only for you – everyone should get the same experimental result. It has to be true for everyone.” Robert Ted Daphne

Empiricism: Empiricism: Emphasis on the primacy of objective sense experience. Emphasis on the primacy of objective sense experience. Experiment is justified by consensus of observation. Theory is justified to the extent it fits observation. Experiment is justified by consensus of observation. Theory is justified to the extent it fits observation. Rationalism: Rationalism: Confidence in the mind’s ability to formulate the orderly character of the world as objective laws of nature. Confidence in the mind’s ability to formulate the orderly character of the world as objective laws of nature. Theory is justified by reason and logic. Experiment is justified to the extent it is explained by theory. Theory is justified by reason and logic. Experiment is justified to the extent it is explained by theory. Theory vs. Experiment in the Philosophy of Science Theory Experiment Theory Experiment

Source of knowledge Knowledge is constructed by the individual to make sense of the subjective experiential world. Knowledge is constructed by the individual to make sense of the subjective experiential world. Justification for knowing Justification by “viability” – Coherence between perception and conception (experiment and theory). Justification by “viability” – Coherence between perception and conception (experiment and theory). Theory vs. Experiment in the Philosophy of Science Constructivism:

Analysis of lab reports and lab practice Results : Analysis of lab reports and lab practice The dimensions, which showed to be of greatest contradiction between the three students: The dimensions, which showed to be of greatest contradiction between the three students: 1) 1)Stating the objective of the experiment. 2) 2)Emphasis in preparation for an experiment. 3) 3)Looking for sources of errors and analyzing them. 4) 4)Arriving to conclusions (in case of differences between the expected outcome and the experimental results).

Preparing for an experiment Preparing for an experiment “I summarize the theoretical background, write the main concepts, read the procedure, so I will know what is going on in the experiment.” “ I concentrated on the main concepts, so at least I will have the basis. To understand what it is all about. After I will do the lab, it will all become clearer. ” “ I tried to understand for each step, why I am supposed to do this or that, why I need acidic environment, what will happen if not ” Robert Ted Daphne Analysis of lab reports and lab practice

[While receiving a buffer capacity which is 1.5 bigger for a diluted solution] “There is a correspondence between the buffer capacity and the dilution- the more concentrated the buffer is, the bigger the buffer capacity.” (Ted) [While receiving a buffer capacity which is 1.5 bigger for a diluted solution] “There is a correspondence between the buffer capacity and the dilution- the more concentrated the buffer is, the bigger the buffer capacity.” (Ted) Analysis of lab reports and lab practice Arriving to conclusions (Buffers lab report) [While receiving that the capacity of diluted and non-diluted solutions is the same] “When you compare the graphs of diluted buffer solutions, it seems that both the solutions have the same efficiency, since the slope in both graphs is similar.” (Daphne) [While receiving that the capacity of diluted and non-diluted solutions is the same] “When you compare the graphs of diluted buffer solutions, it seems that both the solutions have the same efficiency, since the slope in both graphs is similar.” (Daphne)

Conclusions The relative weight each student had in regard to theory vs. experimental evidence, reflected clearly in their approach to lab work  high correlation between the students’ views about NOS and their lab practice. Perception of one component as absolute and objective, and the other as tentative and subjective might lead to: Dissociated view of knowledge in science. Disregard for one component in a case of conflict.

Integrating epistemological awareness as a component in teaching and instruction:  A workshop for lab instructors, based on the lab reports analysis, using concrete examples (Under construction).  Providing proper feedback to students on their lab reports might encourage them to coordinate theory and evidence. Educational Implications

Thank You