Teaching: Some Methods For Teaching Science

                       Introduction 

There are various methods for teaching and learning science that one cannot easily pinpoint a single best method. However, it's the prevailing circumstances or conditions which usually determined the selection of a method or group of methods. 

Some of the methods are: lecture, demonstration, discovery, discussion, project, laboratory, field trip and excursion. 

In selecting an appropriate method, the flowing guidelines or criteria may be used:

1. Students or pupils'characteristics: age, previous knowledge, ability, etc. 

2. Suitability or relevance of the method to the topic. 

3. Familiarity: ie a known or familiar method to the teacher. 

4. Time of the lesson. 

5. Size of the class: (NB: some methods are not suitable for large classes). 

6. Availabile resources: which often determine or guide choice of a method. 

Lecture Method (Talk-Chalk Method) 

This entails verbal or oral presentation of ideas, facts, concepts, etc, in order to provide the pupils or students with information. In this method, which is teacher centred, the teacher does most of the taking or activity while the pupils or students are eithwrpassive listeners or partially involved learners. 

The lecturer method is purported to comprise up to 80% of all science teaching in schools, presumably due to too much emphasis on paper qualifications and passing examinations. However, the method is known to facilitate faster and easier coverage of large content areas than other methods and may be improved through (a) a good command of the language of instructions and (b) clear, legible and bold writing on the chalk board. 

       Advantages of Lecture Method

1. It's economical interns of time and effort and it's non costly and poses only a few challenges. 

2. It facilitates coverage of the course syllabus within the time allotted. 

3. It's the best method for large classes (of 50 or more pupils or students) 

       Disadvantages of Lecture Method

1. It appeals more to the sense of hearing at the expense of others and meaningful learning. 

2. It can hardly meet the different needs of all the learners especially in mix-ability classes. 

3. It often less to restlessness, distruptivness and boredom (it has been found that learners'attention span is just 15 minutes after which restlessness and boredom may set in). 

4. It encourages regurgitation of memorised  facts and write learning (especially where the leaders lack good command of language of instruction and communication skills. 

Guidelines for improving the Lecture Method

1. Improving learner's involvement in the teaching and learning activity through questioning and simple activities rather than just meet verbal engagement. 

2. Raising and maintaining the level of interaction (ie teacher-pupil and pupil-pupil interaction). 

3. Minimising the use of the lecture method for discharging facts in favour of teaching and learning concepts, principles and generalisations. 

4. Using the lecture method in combustion with other methods such as demonstration, discussion, etc. 

            Demonstration Method

This is an activity-based method which involves the display of phenomena or things  as well as the manipulation of a apparatus or equipments. 

Usually, the demonstration of an activity or technique is performed by teachers (teachers demonstration), students (students demonstration)  or guests (guest demonstration).  It may be a talking demonstration, silent demonstration, live-demonstration, live talking demonstration, live silent demonstration or indirect demonstration through visual and audiovisual. 

            Advantages of Method

1. It's a powerful motivator of learning which may be clearly used to introduce, mobilise or end a lesson. 

2. It can be used to save time and materials where each or both are limited. 

3. It's the best method for teaching and learning techniques: 

e.g. how to conduct an experiment correctly. 

How to rotate correctly.

How to set up a microscope correctly. etc

4. It helps to repeat (famous) experiments for the sake of review, testing hypotheses or self-satisfaction. 

5. It can be used to cover experiments that are too risky or too dangerous for students or pupils (eg xanthoproteic food test, irradiation experiments, etc.) 

   Disadvantages of Demonstration Method

1. It relies heavily on the sense of sight which is not good enough condition for effective learning. 

2. It may not encourage interaction with material or apparatus (students or pupils end up unfamiliar with important basic equipment). 

3. Consequently it may not encourage development of manipulative skills and psychological satisfayof the students or pupils. 

4. It may cause difficulties as a result of:

- crowdiness (or overcrowdiness), 

- poor visibility of the demonstration, 

- and too much demonstration. 

 Guidelines For Improvement of Demonstration Method 

1. Demonstration should be used with high degree of certainty about it's success. 

2. Demonstration should be carefully selected and planned for positive results. 

3. There should be adequate visibility for all students or pupils. 

4. Demonstration should be used in conjunction with other methods. 

              Laboratory Method

This method entails carrying out activity by an individual or group for the purpose of making personal observations of processes, products and events. It has also been used for the purpose of:

1. Verification of science principles, laws and theories already known to students or pupils. 

2. Practising one or more of the cognitive skills such as observing, classifying, measuring and interpreting data. 

3. Determining the relationship between cause and effect. 

4. Obtaining and understanding scientific knowledge. 

     Advantages of Laboratory Method

It enables students to:

1. Develop manipulative skills, eg using the microscope, balance, burner, rheostat, etc. 

2. Repeat some of the classic experiments in science. 

3. Be familiar with mental processes, eg observing, offering, classifying, measuring, etc. 

4. Develop rational thinking, critical thinking and scientific attitudes. 

Guidelines For Use of The Laboratory Method

1. Simple and clear procedures should be used. 

2. Method should be comprehensive enough to enable results to be obtained within the allotted time. 

3. Ensure students familiarity with equipment and materials before using them. 

4. The work should be based on the students' background.

5. The teacher's role should be that if a facilitator and guide. 

Individualised Instructional Method

Most methods for teaching and learning science and art do emphasize, group learning which always assumes that all pupils or learners cover the same content over a given period. Contrarily, learners are not alike in many respects, viz their needs, interests, motivation and abilities.

The Individualized Instruction Method (I.I.M) adopts the individual approach to learning because learning according to Bruner (1971) is an individual matter no matter how many pupils or students are there for it. The IIM is a program instruction in which learning programs presented in carefully structu5red steps depending on the:

Nature of the contents

Individual students 

Most individualized packages provide information about results and a feedback mechanism (or self-check mechanism) which will enable the students to discover the causes of errors and make amends.

ADVANTAGES OF INDIVIDUALIZED INSTRUCTIONAL METHODS

The method enables students to proceed at their own pace.

There is a continuous participation or involvement of learners in the learning process.

New material is only introduced after it has been adequately evaluated.

It can serve as an effective and immediate make up for lack of background.

It can supplement inadequate classroom presentations.

The feedback mechanism reduces student anxiety.

DISADVANTAGES OF INDIVIDUALIZED INSTRUCTIONAL METHOD  

It dwells more on two domains of knowledge (cognitive and psychomotor)

The method is time–consuming and makes high demands on materials for equipment.

No cooperative attitude and interpersonal relationships since group interaction is completely missing.

FIELD TRIPS & EXCURSION’S METHOD

A field trip or excursion is often undertaken  outside the classroom for the purpose of proper observation of phenomena, studying relationships and manipulating objects.

Field trip (excursion) is in fact an important, necessary part of a science programme that can give students the opportunity to observe, enjoy and appreciate the orderliness and beauty of nature. It is indeed one of the most enjoyable and exciting experiences for science students.

ADVANTAGE OF FIELD TRIP METHOD

The method provides opportunity for conducting activities that are too noisy or too dangerous in the classroom.

It sharpens student’s keenness in observation and other skills especially as it make demand on the use of all senses.

It provides opportunity to see reality and nature laws in preparation.

It improves interpersonal relationships and development of cooperative attitude.

DISADVANTAGE OF FIELD TRIP METHOD 

It is more time consuming than class work.

It is an additional financial burden on the authority and the individuals involved.

Accidents are more liable to occur in field trips than in class work.

The administration of a field trip, its planning and execution is tedious.

GUIDELINES FOR EFFECTIVE USE OF FIELD TRIP 

Previsit: The teacher must first make a previsit of the site in order to ascertain all possible features of the place, endowment, opportunities, dangers, obstacles etc.

Transport: planning for the journey (to and fro) conditions, safety, vehicles etc.

First aid kits: Must be readily available during the trip.

Informing: participants should be informed about (a) aims and objectives and methods of the trip (b) all possible material requirement for the trip.

Convene a class discussion on the activities during the trip as well as student’s report at the end of it.

DISCOVERY METHOD 

This is a teaching or learning method which involves an unstructured exploration of nature in which the student is expected to use mental processes (e.g observing, measuring and classifying) to draw general conclusions from available gatehered data. The method generally proposes that certain sevence concepts, facts or ideas should not be taught too directly but that the number of modern science curricula which emphasise pupils’ involvement in science activities through discovery experiences and many are following suit.

Guided discovery (or guided inquiry)

Free/pure discovery can either be (a) deductive or (b) inductive in its mode of instruction.

In deductive guided discovery, the general principle of a phenomena is provided and the learners (pupils) are expected to use it to discover the soluition to a specific problem. This mode therefore involves movement from general principles to facts, or from the general to the particular (or specific).

Example: designing experiments to verify Boyle’s law, Charle’s law, Mendel’s law etc.

In inductive guided discovery however, the solution to a scientific problem is provided and the pupils are expect to discover the general principle on which the solution is based.  The mode involves movements from the particular (or specific) to the general. Obviously, general principles can be discovered from available gathered facts. Example: using induction to discover generalization e.g the fact that “shorter pendula swing aster than longer pendula” can be used to derive / discover the relationship about, period of swing.

FREE (OR PURE) DISCOVERY (UNGUIDED INQUIRY)

In this case neither the general principle nor the solution to the problem is provided, rather than pupil is expected to discover both through his activity. 

NB: both guided discovery and free discovery methods are complex in that they expect extensive use of mental processes and skills by pupils processes which involve higher mental activity expected of full-fledged scientists with many years of doing science experience behind them. To expect pupils (children) to do so would therefore be unwise. This is the view of professor Rosalind Driver and others.

These mental processes or skills are components of the scientific method of inquiry or investigation:

Identifying problem to be investigated

Formulating hypotheses to guide the investigation 

Designing experiments to collect data

Generalizing (or finding solution to the problem)

Developing scientific attitudes (e.g objectivity, curiosity and open-mindedness).

ADVANTAGES OF DISCOVERY METHOD

It is a means of obtaining knowledge by oneself thereby facilitating mental development (or maturity) and critical (or analytical) thinking.

It leads to achievement of independence and self-reliance (by making the learners to search and find out things for themselves.

It aids assimilation and retention of knowledge since it is based on direct, first-hand experience.

It facilitates the development of manipulative skills.

DISADVANTAGES OF DISCOVERY METHOD

It is usually slow and time-consuming 

It is basically pupil-centered and therefore unpredictable and more or less ineffective.

It is more or less indifferent to content and the syllabus.

It is apparently more costly than other methods.

Recommended Use of Discovery Method

It should be used in conjunction with:

A moderately-structured lesson for the purpose of guidance

Discussion i.e a pre-discussion before making discovery and post-activity discussion to discuss relevant questions.

Continued trial in conjunction with other methods 

Group work may be necessary when dealing with large classes.

DISCUSSION METHOD 

Discussion is the act of talking about subject or topics or issues or problems from various points of view. It is student-centered and based on the  philosophy that a knowledge’s arises from with the person not an external source”. The teacher’s role in discussion method is not to dispense or communicate knowledge but to act as a moderator in the exercise. Moderator in the exercise. Moderator however does not imply dictating terms or influencing decisions. Rather, the students are allowed to express their points of view in a relaxed atmosphere. Motivation for the student’s discussion should come in the form of carefully-framed teacher’s questions that can elicit reasoning rather than recall.

ADVANTAGES OF DISCUSSION METHOD

Activity – based lessons can be introduced through discussion

Interpersonal relationship through interaction may be promoted (I.e pupil-pupil and pupil-teacher interaction).

Frequent exchange of ideas can be build confidence in the students.

Students can obtain knowledge on their own through active participation in discussion.

DISADVANTAGE OF DISCUSSION METHOD

The method is usually time consuming

It cannot be used quite often because it doesn’t allow easy coverage of the syllabus.

Certain topics are not suitable for discussion 

Boredom\ and fatique ay result when the topic lacks a good background.

The topic must be stimulating enough because of the limited attention span of pupils.

GUIDELINES FOR EFFECTIVE USE OF DISCUSSION METHOD

Both the topic of discussion and the moderator’s questions must be at the level of the students or pupils.

Use of qualitative topics: which are not too factual, too ordinary, too farfetched and hardly understood.

The moderation should be good and efficient 

Good questioning technique is a pre-requisite; good questions that will elicit reflexive thinking as well as critical thinking should be used. Vague, rhetorical questions should be avoided.

Good acquaintance of the leader of discussion with the topic, which will be shown by his ability to break the total learning product into its components parts.

A good teacher summary may be necessary in order to facilitate understanding of subsumed concepts and principles.

PROJECT METHOD OF TEACHING 

The project method is often aimed at individualism instruction by providing for the needs of the individual and small groups of students so that those with special talents may fulfil them. It usually gives students relative freedom to look for problems that are of special interest to them and search for their solutions without having much prior knowledge about them. It is by no means a verification exercise aimed at confirming simple facts and principles. It will however elicit some bit of originality on the part of the students and help teacher to get closer to meeting individual student’s needs. A good method for teaching learning normally satisfies group and individual needs of the pupils or students.

SOME SOURCES OF PROJECT TOPICS

Project copies for students may be obtainable through a number of sources e.g:

Student – student or pupil – pupil interaction 

Readings in scientific journals and magazines

Abstracts from paper presented by scientists

Reports from science seminars and workshops.

Classroom experience on particular topics

Science and art text books

Visits and field trips.