Undergraduate Students’ Laboratory Practice Illuminated by The Philosophy of Science TheoryVs....

Undergraduate Students’ Undergraduate Students’ Laboratory PracticeLaboratory Practice

Illuminated by Illuminated by The Philosophy of ScienceThe Philosophy of Science

Theory Theory Vs.Vs.

Experimental EvidenceExperimental Evidence.

Rachel Havdala Guy Ashkenazi

Dept. of Science Teaching, The Hebrew University of Jerusalem

MotivationMotivationScience students show great difficulties in coordinating Science students show great difficulties in coordinating

their lab results with the theory they learned in classtheir lab results with the theory they learned in class

AimAim

To find ways to enhance the coordination between To find ways to enhance the coordination between

theory and experimental evidencetheory and experimental evidence

MethodMethod

Interviews - students views about the nature of Interviews - students views about the nature of

science science

Lab reports analysis Lab reports analysis

QuestionQuestion

Is there any correlation between the students’ views Is there any correlation between the students’ views

about NOS and their lab practice?about NOS and their lab practice?

Personal Personal EpistemologyEpistemology

A continuum in the perception of knowledgeA continuum in the perception of knowledge

ObservatioObservation or n or

ReasonabiliReasonabilityty

Assessment and

Integration

ExternalExternal

,,

ObjectivObjectiv

ee

ConstructeConstructe

d,d,

SubjectiveSubjective

Source of Knowledge

Justification for knowing

(Hoffer, 2004)(Hoffer, 2004)

The main components The main components of knowledge in of knowledge in

sciencescience

Experiment

Theory

Empiricism:Empiricism: Emphasis on the primacy of Emphasis on the primacy of objectiveobjective sense experience. sense experience.

Experiment is justified by consensus of Experiment is justified by consensus of observationobservation. Theory . Theory

is justified to the extent it fits observation.is justified to the extent it fits observation.

Rationalism:Rationalism: Confidence in the mind’s ability to formulate the orderly Confidence in the mind’s ability to formulate the orderly

character of the world as character of the world as objectiveobjective laws of nature. laws of nature.

Theory is justified by Theory is justified by reasonreason and logic. Experiment is justified and logic. Experiment is justified

to the extent it is explained by theory.to the extent it is explained by theory.

Theory vs. Experiment Theory vs. Experiment in the Philosophy of in the Philosophy of

ScienceScienceTheory

Experiment

TheoryExperiment

Source of knowledgeSource of knowledge

Knowledge is constructed by the individual to make Knowledge is constructed by the individual to make

sense of the sense of the subjective subjective experiential world.experiential world.

Justification for knowing Justification for knowing

Justification by “viability” – Justification by “viability” – CoherenceCoherence between between

perception and conception (experiment and theory).perception and conception (experiment and theory).


ScienceScience

Constructivism:Constructivism:

Primary Analysis of lab reports (General chemistry Primary Analysis of lab reports (General chemistry

lab for chemists, consists of 8 lab sessions).lab for chemists, consists of 8 lab sessions). Choosing students for interviews Choosing students for interviews (12 from 2004, 13

from 2005 - 25 total).

Primary analysis of interviews.Primary analysis of interviews. Selection of three students :Selection of three students :

– Very decisive and consistent views about science.Very decisive and consistent views about science.

– Greatest disparity.Greatest disparity.

– Belonged to the same lab group (from the class of 2004).Belonged to the same lab group (from the class of 2004).

The Analytical The Analytical ProcessProcess

Primary analysis

Results :Views about NOS

The dimensions, which showed to be of The dimensions, which showed to be of

greatest contradiction between the three greatest contradiction between the three

students:students:

1) The basic component of knowledge in science.

2) The purpose of scientific work.

3) Main characteristics of science.

4) The role of mathematics in science.

5) Science in the students’ laboratory.

Views about Views about NOSNOS

Q: How would you define a scientific law?Q: How would you define a scientific law?

A: It is something experimental, for sure…A: It is something experimental, for sure…

Q: What is it based upon?Q: What is it based upon?

A: Only on experiment. […] A: Only on experiment. […] First you need First you need

the experiment and then it will be the experiment and then it will be

accurateaccurate. […] As long as it is proved . […] As long as it is proved

by an experiment, it is good. by an experiment, it is good.

The basic component of The basic component of knowledge in scienceknowledge in science

(Daphne)(Daphne)


Q: How does a scientist tries to think? Q: How does a scientist tries to think?

Does he rely on assumptions or on Does he rely on assumptions or on

facts?facts?

A: I believe he has to rely on A: I believe he has to rely on

assumptions. You cannot know how a assumptions. You cannot know how a

substance will behave in advance. You substance will behave in advance. You

need to take some assumptions and need to take some assumptions and

try to make facts out of them.try to make facts out of them.


(Ted)(Ted)


You cannot generalize. Every law has You cannot generalize. Every law has

its own history. If someone got hit by its own history. If someone got hit by

an apple on his head… Sometimes an apple on his head… Sometimes

the theory comes first, sometimes the theory comes first, sometimes

the experiment. the experiment. It's a combination, It's a combination,

always a combination.always a combination.


(Robert(Robert))

““Even those natural laws that we don’t know Even those natural laws that we don’t know behave mathematically. This is what I believe.”behave mathematically. This is what I believe.”

Personal Personal PhilosophyPhilosophy

Source of KnowledgeSource of Knowledge

““If I didn’t know that these results are If I didn’t know that these results are already known, would it matter to me? It already known, would it matter to me? It doesn’t matter – for doesn’t matter – for meme it is new… it is it is new… it is my own private research. For me that is my own private research. For me that is sufficient.”sufficient.”

““A scientific law… is generally discovered A scientific law… is generally discovered by chance, and then you do experiments by chance, and then you do experiments to verify it.”to verify it.”

RoberRobertt

TedTed

DaphnDaphnee

““Mathematics helps base certain theories, or Mathematics helps base certain theories, or invent new ones – you just see that a certain invent new ones – you just see that a certain equation fits a certain experiment.”equation fits a certain experiment.”

Personal Personal PhilosophyPhilosophy

Justification of knowledgeJustification of knowledge

““It is true for now. What was written 200 It is true for now. What was written 200 years ago was true 200 years ago… years ago was true 200 years ago… When they tell you the law, it works… If When they tell you the law, it works… If you don’t have a problem, you will take it you don’t have a problem, you will take it for granted.” for granted.”

““You need it to be objective, not only for You need it to be objective, not only for you – everyone should get the same you – everyone should get the same experimental result. It has to be true for experimental result. It has to be true for everyone.”everyone.”

RoberRobertt

TedTed

DaphnDaphnee

Empiricism:Empiricism: Emphasis on the primacy of Emphasis on the primacy of objectiveobjective sense experience. sense experience.

Experiment is justified by consensus of Experiment is justified by consensus of observationobservation. Theory . Theory

is justified to the extent it fits observation.is justified to the extent it fits observation.

Rationalism:Rationalism: Confidence in the mind’s ability to formulate the orderly Confidence in the mind’s ability to formulate the orderly

character of the world as character of the world as objectiveobjective laws of nature. laws of nature.

Theory is justified by Theory is justified by reasonreason and logic. Experiment is justified and logic. Experiment is justified

to the extent it is explained by theory.to the extent it is explained by theory.


ScienceScienceTheory

Experiment

TheoryExperiment

Source of knowledgeSource of knowledge

Knowledge is constructed by the individual to make Knowledge is constructed by the individual to make

sense of the sense of the subjective subjective experiential world.experiential world.

Justification for knowing Justification for knowing

Justification by “viability” – Justification by “viability” – CoherenceCoherence between between

perception and conception (experiment and theory).perception and conception (experiment and theory).


ScienceScience

Constructivism:Constructivism:

Results : Analysis of lab reports Analysis of lab reports

and lab practiceand lab practice The dimensions, which showed to be of greatest The dimensions, which showed to be of greatest

contradiction between the three students:contradiction between the three students:

1) Stating the objective of the experiment.

2) Emphasis in preparation for an experiment.

3) Looking for sources of errors and analyzing them.

4) Arriving to conclusions (in case of differences

between the expected outcome and the

experimental results).

Preparing for an experimentPreparing for an experiment

““I summarize the theoretical background, I summarize the theoretical background,

write the main concepts, read the write the main concepts, read the

procedure, so I will know procedure, so I will know whatwhat is going on is going on

in the experiment.”in the experiment.”

““I concentrated on the main concepts, so at I concentrated on the main concepts, so at

least I will have the basis. To understand least I will have the basis. To understand

whatwhat it is all about. After I will do the lab, it it is all about. After I will do the lab, it

will all become clearer.” will all become clearer.”

““I tried to understand for each step, I tried to understand for each step, whywhy I I

am supposed to do this or that, why I need am supposed to do this or that, why I need

acidic environment, what will happen if acidic environment, what will happen if

not”not”

RoberRobertt

TedTed

DaphnDaphnee

Analysis of lab Analysis of lab reports and lab reports and lab

practicepractice

[While receiving a buffer capacity which is 1.5 bigger for a [While receiving a buffer capacity which is 1.5 bigger for a

diluted solution] “There is a correspondence between the diluted solution] “There is a correspondence between the

buffer capacity and the dilution- the more concentrated buffer capacity and the dilution- the more concentrated

the buffer is, the bigger the buffer capacity.” the buffer is, the bigger the buffer capacity.” (Ted)(Ted)

Analysis of lab Analysis of lab reports and lab reports and lab

practicepracticeArriving to conclusions

(Buffers lab report)(Buffers lab report)

[While receiving that the capacity of diluted and non-diluted [While receiving that the capacity of diluted and non-diluted

solutions is the same] “When you compare the graphs of solutions is the same] “When you compare the graphs of

diluted buffer solutions, it seems that both the solutions have diluted buffer solutions, it seems that both the solutions have

the same efficiency, since the slope in both graphs is similar.” the same efficiency, since the slope in both graphs is similar.”

(Daphne)(Daphne)

ConclusionsConclusionsThe relative weight each student had in regard to The relative weight each student had in regard to

theory vs. experimental evidence, reflected clearly theory vs. experimental evidence, reflected clearly

in their approach to lab work in their approach to lab work high correlation high correlation

between the students’ views about NOS and their between the students’ views about NOS and their

lab practice.lab practice.

Perception of one component as absolute and Perception of one component as absolute and

objective, and the other as tentative and objective, and the other as tentative and

subjective might lead to:subjective might lead to:

Dissociated view of knowledge in science.Dissociated view of knowledge in science.

Disregard for one component in a case of Disregard for one component in a case of

conflict.conflict.

Integrating epistemological awareness as a Integrating epistemological awareness as a

component in teaching and instruction:component in teaching and instruction:

A workshop for lab instructors, based on the A workshop for lab instructors, based on the

lab reports analysis, using concrete examples lab reports analysis, using concrete examples

(Under construction).(Under construction).

Providing proper feedback to students on their Providing proper feedback to students on their

lab reports might encourage them to coordinate lab reports might encourage them to coordinate

theory and evidence.theory and evidence.

Educational ImplicationsEducational Implications

Thank You

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