B.Ed. Notes- THEORETICAL BASES OF TEACHING PHYSICAL SCIENCE : UNIT. VI – Scientific Method

THEORETICAL BASES OF TEACHING PHYSICAL SCIENCE

UNIT. VI – Scientific Method

Prepared by

SABARISH-P

M.Sc., M.Ed., JRF & NET

Assistant Professor in Physical Science, Arafa Institute for Teacher Education

Attur, Thrissur.

Contact me : pklsabarish@gmail.com

Science and Philosophy

Science and philosophy have a very long history, back at least to the 16th and 17th centuries, when the first scientist-philosophers, such as Bacon, Galilei, Aristotle and Newton, were beginning the process of turning natural philosophy into science. Science and philosophy have always learned from each other. Philosophy tirelessly draws from scientific discoveries fresh strength, material for broad generalisations, while to the sciences philosophy imparts the world-view and methodological impulses of its universal principles. Many general guiding ideas that lie at the foundation of modern science were first enunciated by the force of philosophical thoughts. One example is the idea of the “atom” is voiced by Democritus and Indian Philosopher Kanada Maharshi. The idea of the existence of molecules as complex particles consisting of atoms was developed in the works of the French philosopher Pierre Gassendi and also Russia's Mikhail Lomonosov. Lenin formulated one of the fundamental ideas of contemporary natural science—the principle of the inexhaustibility of matter—upon which scientists rely as a firm methodological foundation.

The latest theories of the unity of matter, motion, space and time, the unity of the discontinuous and continuous, the principles of the conservation of matter and motion, the ideas of the infinity and inexhaustibility of matter were stated in a general form in philosophy. Every major scientific discovery is at the same time a step forward in the development of the philosophical world-view and methodology. Philosophical statements are based on sets of facts studied by the sciences and also on the system of propositions, principles, concepts and laws discovered through the generalisation of these facts. The achievements of the specialised sciences are summed up in philosophical statements. Euclidian geometry, the mechanics of Galileo and Newton, were great achievements of human reason which played 'a significant role in forming world-views and methodology. Copernicus' heliocentric system changed the whole conception of the structure of the universe. Darwin's theory of evolution, which had a profound impact on biological science in general and our whole conception of man's place in nature. Einstein's theory of relativity changed our notion of the relationship between matter, motion, space and time.

Scientists in their specific researches, in constructing hypotheses and theories have constantly applied world-views and methodological principles, categories and logical systems evolved by philosophers. All scientists who think in terms of theory constantly speak with a deep feeling of gratitude to philosophers.

The ideas of positivism, constructivism, epistemology, etc have clear scientific-philosophical background.

So the connection between philosophy and science is mutual and characterized by their ever deepening interaction.

Scientific Method

Ø  Scientific method is the procedure adopted by scientists in their investigation

Ø  Scientific method is a systematic and orderly method of solving problems.

Ø  ‘Scientific Method consists of systematic observation, classification and interpretation of data’- Lundberg

Note: Problem solving method should not be confused with the scientific method. Problem solving method is a teaching method which incorporates the principles of the Scientific method. The scientific method is a method of finding truth in science. Problem solving method is a teaching method.

Importance of scientific method

1)      Scientific method attempts to minimize the influence of bias or prejudice in the experimenter.

2)      It provides an objective, standardized approach to conducting experiments and, in doing so, improves their results.

3)      Using the scientific method regularly will teach the student to look at all the evidence before making a statement of fact, which makes it an integral part of science education.

4)      This method teaches the student to analyze and process the information he is receiving. 

5)      It trains the brain to logically examine and process all the information it receives

Steps of Scientific Method

Ø  Sensing the problem

A felt difficulty

You feel the problem only when you get involved in it.

Teacher should make students involve in the scientific problem.

Ø  Defining the problem

Students define the problem in a concise definite and clear language.

There should be some key words in the definition.

Teacher may assist in defining

Ø  Analysing the problem

Meaningful break down of the problem and its causes can lead to its solution. Analysis of the problem would help to collect the relevant data/evidence upon the problem.

Ø  Collecting the data

Relevant details are collected from experts /reference books/ or from firsthand experience.

Ø  Interpreting data.

After collecting data it have to be critically examined with respect to relevance, appropriateness, clarity etc

Ø  Formulation of hypothesis

Through analysis/ synthesis/ logical inference, several probable solutions are arrived at.

Ø  Testing Hypothesis.

Finding out the bearings of the hypothesis

The hypotheses are scrutinized using actual testing or logical reasoning.  If the implications agree with the observed facts, they are accepted others are rejected.

Ø  Confirmation and generalization through experiments.

The tested hypothesis if accepted leads to the conclusion to be formed. Generalisations can be made if similar sets of experiments also show the same results.

Ø  Applications of generalization to new situations

The conclusions are subjected to rigorous and repeated tests and are generalized to wider areas.

Logical Process in Scientific Method

The logical process in scientific method is in no way different from the thought processes of an ordinary person. It comprises of

·         A felt difficulty

·         Its definition

·         Suggestion of probable solution

·         Selecting the most likely hypothesis by reasoning.

Logical elements/aspects in scientific method

All logical elements are inferential processes which reveal the cause effect relationship.

Ø  Induction

·         Advocated by Francis Bacon

·         It is proving general truths.

·         When particular cases are found true it is generalized and accepted as a universal truth

·         It proceeds from particular to general

·         From known to unknown

·         Induction is inferring a generalized statement from instances.

·         Mills Five canons of Induction*. Mills canons are used when there is a plurality (more than one) of causes.

*Mills Five canons of Induction

Mill's five cannons are five methods of induction described by philosopher John Stuart Mill They are intended to illuminate causation (Find the cause).

1) Method of agreement

Statement: If two or more instances of the phenomenon under investigation have only one circumstance in common, that circumstance is probably the cause (or effect) of the given phenomenon.

For Example

A B C D occur together with w x y z

A E F G occur together with w t u v

——————————————————

Therefore A is the cause, or the effect, of w.

2) Method of difference

Statement: Whenever the elimination of a single circumstance is accompanied by the nonoccurrence of a phenomenon that circumstance is probably related to its causation.

For Example

A B C D occur together with w x y z

B C D occur together with x y z

——————————————————

Therefore A is the cause, or the effect, or a part of the cause of w.

3) Joint method of agreement and difference

Statement: If in a group of cases in which a phenomenon occurs there is one and only one common circumstance, while in another group of cases in which the phenomenon does not occur there is nothing in common except the absence of the above circumstance, then the phenomenon is causally related to that circumstance..

For Example

A B C occur together with x y z

A D E occur together with x v w also B C occur with y z

——————————————————

Therefore A is the cause, or the effect, or a part of the cause of x.

4) Method of residue

Statement: If part of complex phenomenon is known to be causally related to certain operating circumstances the residual part of the phenomenon must be due to the rest of the relevant circumstances..

For Example

A B C occur together with x y z

B is known to be the cause of y

C is known to be the cause of z

——————————————————

Therefore A is the cause or effect of x.

5) Method of concomitant variations

Statement: If two phenomena vary concomitantly, while all other relevant circumstances remain unchanged, they must be casually related.

For example

A B C occur together with x y z

A± B C results in x± y z.

—————————————————————

Therefore A and x are causally connected

LIMITATIONS OF MILL’S METHODS

• First, the rules presuppose that we have a list of candidate causes to consider. But the rules themselves do not tell us how to come up with such a list.

• The other assumption presupposed by these methods is that among the list of factors under consideration, only one factor is the unique cause of the effect. But there is no guarantee that this assumption always holds. Also, sometimes the cause might be some complicated combinations of various factors.

Ø  Deduction

·         Advocated by Aristotle

·         It is the process of reasoning that starts from an accepted generalization and moves towards a specific instance

·         For deduction, 3 statements and not more than three are required.

Example: All men are mortal  | (Major premise must be true)

 All kings are men    | (Argument must be valid)

 All kings are mortal| (Conclusion follows naturally)

Ø  Analogy

·         It is a relation of resemblance between two objects

·         By using an analogy a new idea is presented in the meaningful context of a familiar idea.

·         This helps a new learner to acquire the idea more easily.

Example : Atomic structure and solar system

Ø  Analysis

·         Separating into parts

·         Things and events of nature are mostly complex.  To find the cause –effect relationship we may have to breakdown the complex event into simpler events.

Ø  Synthesis

·         Nature has presented ideas which are closely combined and unified into a whole.Therefore the whole is more important than the parts.

·         It is important that the constituent facts, laws and relations fit in among themselves so that it will justify the whole.

Eg. How is nucleus stable with positive protons closely packed?

Ø  Testimony

·         It is personal or documentary evidence.

Eg. University certificates, land documents, Manuscripts of Scientists,  CRC book etc

Ø  Authority

It refers to the right to give an ultimate decision. Authority and testimony are sources of knowledge.

eg. Court, Survey of India, Election Commission, ISRO, NASA etc.

Ø  Hypothesis

·         Hypothesis is an intelligent guess adopted provisionally to explain the observed facts which guide in further investigation. Depth of knowledge, Imagination, genuine interest in the subject help in framing  fruitful hypothesis

Purposes of Hypothesis

·         Provides a tentative explanation

·         Gives direction to the investigation

·         Gives a relationship that is testable.

·         Provides a framework for reporting the conclusion

Criteria of a good hypothesis

·         It must have explanatory power

·         It must be consistent with universal laws

·         It should be simple stated clearly and precisely

·         It should be testable

·         It should be adequate enough to explain the observed facts.

Different types of hypotheses

·         Null form

·         Non directional form

·         Directional form

·         Statement form

·         Question form

Technical aspects of Scientific Method

The technical aspects of Scientific method includes - Observation, Experiment & Data Collection

Observation

·         Observation means prolonged perception of things / events directed and sustained by attention.

·         It involves mental processes like attention, selection, analysis, classification etc.

Experimentation

·         Experiment is active observation

·         It is controlled observation

·         Observation of phenomenon under controlled conditions is called experiment.

Eg: Projectile - u, θ  (independent variable) we vary them,

R (range) (dependent variable) changes occur in them.

Observation	Experiment
Not quiet objective (Personal bias of observer can influence inferences)	Reliable and objective than observation
Affected by external elements like defect of sense organ, other unwanted outside situations etc.	Most of the unwanted elements are controlled.

Data Collection

(Be familiar with concepts like population, sampling etc. Study in Detail from any science education text/ visit sabarishedn.blogsot.in)

A Population is the collection of all elements or events that have one or more characteristics in common that the scientist is interested in. An entire population can be studied. Many times it may not be possible to study the whole population due to various reasons such as time and effort needed. Hence investigator uses the technique of sampling. Sampling is the process of selecting units from a population of interest so that by studying the sample we can fairly generalize the results to the population from which the units where choosen. Population sampling is the process of taking a subset of subjects that is representative of the entire population. The sample must have sufficient size to warrant statistical analysis.

A sample is a subset of people, items, or events from a larger population that you collect and analyze to make inferences. To represent the population well, a sample should be randomly collected and adequately large. If the sample is random and large enough, you can use the information collected from the sample to make inferences about the population.

Various sources of data collection that can be used by students.

n  Experiments

n  Interview with experts

n  Survey using tools like questionnaire, inventory, rating scale etc

n  Textbooks/ Reference books etc

n  Field Trip,

n  Internet etc…..

Ø  Hypothetico- deductive method

A method in which a hypothetical model based on observations is proposed and is then tested by the deduction. The hypothetical-deductive method (HD method) is a very important method for testing theories or hypotheses.

The hypothetical-deductive method

·         Identify the hypothesis to be tested.

·         Generate predictions from the hypothesis. (Mainly by deductive reasoning)

·         Use experiments to check whether predictions are correct.

·         If the predictions are correct, then the hypothesis is confirmed. If not, then the hypothesis is disconfirmed.

The hypothetico-deductive method is often regarded as the only 'true' scientific research method. The method involves the traditional steps of observing the subject, in order to elaborate upon an area of study. This allows generating a testable and realistic hypothesis.

From the hypothesis, the researcher must generate some initial predictions, which can be proved, or disproved, by the experimental process. These predictions must be inherently testable for the hypothetico-deductive method to be a valid process.

Ø  Inductive Reasoning

Inductive reasoning is the process where a small observation is used to infer a larger theory, without necessarily proving it. Most scientists use this method to generate theories about how the universe works and discover the laws governing our very existence. Many ancient philosophers used induction for making observations and constructing theories. For example, the Ancient Greek philosophers believed that theories could be proved by logic alone and did not need experiments. They thought that mathematically strict laws, deduced from smaller observations, governed the universe. In Inductive reasoning an initial observation leads to the discovery of a certain pattern. This allows a tentative prediction to be made which leads to a general theory about how things work.

An excellent example of this process in action is the discoveries and works of the great Charles Darwin.

Ø  Deductive Reasoning

Deductive reasoning is what a researcher starts with a wider theory. The researcher generates a testable hypothesis and designs an experiment to observe the results, and prove or disprove the theory.

J. J. Thompson's Cathode Ray-Experiment was an excellent example of this process, where he had ideas about how electrons behaved and generated theories about their nature.

Therefore, he generated hypotheses, designed experiments and tried to find conclusive answers to add credence and weight to his initial theory.

Transfer value of scientific method

Ø  There is an effect of training in one form of activity upon one’s ability in other fields of activity.

Ø  It is hoped that the training obtained through scientific method can be utilized in solving the problems of one’s life.

Ø  It develops thinking process, Scientific skills, Observation skill, Ability to manipulate Rational behaviour etc

Ø  Habits of this sort once acquired will automatically be generalized and applied to the wider concerns of life.

Strategies to give pupils training in scientific method

Ø  Make pupil do experiments

Ø  Make pupils solve scientific problems

Ø  Demonstrate different scientific equipments and explain the scientific principles behind them.

Ø  Always link the subject matter with real life situations

Ø  Make a science club and let pupils organize scientific activities (quiz, seminar, debate, field trip etc.)

Ø  Present the content to be taught in the form of problems to be solved.

Ø  Make students feel the importance of science in human progress.

Ø  Make students familiar the scientific method adopted by various scientists like Albert Einstein, A.P.J. Abdul Kalam etc in their life/inventions.

Corroboration

Corroboration refers to an extent to which a given theory has withstood severe tests. The severity of tests depends “upon the degree of testability, and thus upon the simplicity of the hypothesis.” 

For example, the statement, “Sun rises every morning.” The evidence for this statement is based on one’s observation of the sun rising every morning all these days. This corroborates the hypothesis that sun will rise every morning, because in case if the sun had not risen on any one of the morning in the past would falsify the hypothesis. Therefore, each morning the hypothesis is tested. All these days, the hypothesis has been found to be true, and every success (i.e., sun rising in the morning) further corroborates the hypothesis more

Falsification

What is Falsifiability?

Karl Popper defines falsifiability as “the inherent testability of any scientific hypothesis.”  In other words, the claims are framed in such a way that the tests can be constructed and proved to be false, provided the claims are false. The hypothesis is framed such that it can be subjected to practical investigations and is also open to rejection by those investigations. Thus, in order to have credibility, any hypothesis should be inherently disprovable before it is accepted as a scientific hypothesis or theory.

For example, if a scientist asks, "Does God exists?" then this can never be science because it is a theory that cannot be disproved.  Therefore, no theory is completely correct, however, if it is not falsified, it may be accepted as truth!!

Popper viewed falsifiability as a straightforward definition, that if a theory is falsifiable, it is scientific, and if not, then it is unscientific.

Consequently, corroboration is linked to falsifiability. According to Popper, the more significantly falsifiable a theory is, the greater is its degree of corroborability.