The dictionary meaning of the word "demonstration" is the outward showing of a feeling etc.; a description and explanation by experiment; so also logically to prove the truth; or a practical display of a piece of equipment to snow its display of a piece of equipment to show its capabilities . In short it is a proof provided by logic, argument etc.

To define "it is a physical display of the form, outline or a substance of object or events for the purpose of increasing knowledge of such objects or events. Demonstration involves showing what or showing how". Demonstration is relatively uncomplicated process in that it does not require extensive verbal elaboration.

Now it will be easy to define what is lecture cum demonstration method.

To begin with, this method includes the merits of lecture method and demonstration method. The teacher performs the experiment in the class and goes on explaining what she does. It takes into account the active participation of the student and is thus not a lopsided process like the lecture method. The students see the actual apparatus and operations and help the teacher in demonstrating experiments and thereby they feel interested in learning. So also this mehod follows maxims from concrete to abstract Wherein the students observe the demonstration critically and try to draw inferences. Thus with help of lecture cum demonstration method their power of observation and reasoning are also exercised. So the important principle on which this method works is "Truth is that works."

The success of any demonstration following points should be kept in mind.

1.It should be planned and rehearsed by the teacher before hand.

2.The apparatus used for demonstration should be big enough to be seen by the whole class. If the class may be disciplined she may allow them to sit on the benches to enable them a better view.

3.Adequate lighting arrangements be made on demonstration table and a proper background table need to be provided.

4.All the pieces of apparatus be placed in order before starting the demonstration. The apparatus likely to be used should be placed in the left hand side of the table and it should be arranged in the same order in which it is likely to be used

5.Before actually starting the demonstration a clear statement about the purpose of demonstration be made to the students.

6.The teacher makes sure that the demonstration lecture method leads to active participation of the students in the process of teaching.

7.The demonstration should be quick and slick and should not appear to linger on unnecessarily.

8.The demonstration should be interesting so that it captures the attention of the students.

9.It would be better if the teacher demonstrates with materials or things the children handles in everyday life.

10.For active participation of students the teacher may call individual student in turn to help him in demonstration.

11.The teacher should write the summary of the principles arrived at because of demonstration on the blackboard. The black board can be also used for drawing the necessary diagrams.

These are some of the requirements of a good demonstrations.

1.Planning and preparation: A great care be taken by the teacher while planning and preparing his demonstration. He should keep the following points I mind while preparing his lesson.

a.Subject matter.

b.Questions to be asked.

c.Apparatus required for the experiment

To achieve the above stated objective the teacher should thoroughly go through the pages of the textbook, relevant to the lesson. After this he should prepare his lesson plan in which he should essentially include the principles to be explained, a lot of experiments to be demonstrated and type of questions to be asked form the students. These questions be arranged in a systematic order to be followed in the class. Before actually demonstrating the experiment to a class, the experiment be rehearsed under the condition prevailing in the classroom. Inspite of this, some thing may go wrong at the actual lesson, so reserve apparatus is often useful the apparatus has to be arranged in a systematic manner on the demonstration table. Thus for the success of demonstration method a teacher has to prepare himself as thoroughly as possible.

2.Introduction of the lesson: As in every subject so also in the case of science the lesson should stat with proper motivation of the students. It is always considered more useful to introduce the lesson in a problematic way which would make the student's realise the importance of the topic. The usual way through which the teacher can introduce the lesson is by telling some personal experience or incident of a simple and interesting experiment. A good experiment carefully demonstrated is likely to leave an everlasting impression on the mind of the young pupils and would set the students talking about it in the school.

3. Presentation: The method presenting the subject matter is very important. A good teacher should present his lesson in an interesting manner and not in an boring manner. To make the lesson interesting the teacher may not be very rigid too remain within the prescribed course rather he or she should make the lesson as much as broad based as possible. For widening the lesson the teacher may think of various useful application taught by him. He is also at the liberty to take examples and illustrations for allied branches of science like history, geography

etc. Constant questions and answer should form a part of every demonstration lesson. Questions and cross question are essential for properly illuminating the principles discussed. Question should be arranged in such a way that their answers may form a complete teaching unit.

4. Performance of experiment: A good observer has been described as a person who has learnt the use the senses of touch, sight, smell in an intelligent way. Through this method we want children to observe what happens in a experiment and to state it carefully. We also want them to make generalization without violating scientific spirit i.e. we should allow children from one experiment or observation. The following steps are generally accepted as valuable in conducting science experiment generally.

a.Write the problem to be solved in simple words.

b.To make a list of activities that has to be used to solve the problem.

c.Gather material for conducting the experiment

d.Work out a format of steps in the order of preocedu8re so that everyone knows

what is to be done.

e.Teacher should try the experiment before conduction. f. Record the findings.

f.Assist students to make generalisation.

5. Black Board Summary: A summary of important results and principles should be written in the Blackboard. Use of blackboard should be also frequently used to draw sketches and diagrams. The entire procedure should be displayed to the students after the demonstration.

6. Supervision: Students are asked to take the complete notes of the black board summary including the sketches and diagrams drawn. Such a record will be quite helpful to the student while learning his lessons .Such a summary will prove beneficial only if it has been copied correctly from the black boards and to make sure that it is done so the teacher must check it frequently during this stage.

Common Errors In Demonstration Lesson

A summary of the common errors committed while delivering a demonstration lesson is

given below:

a)Apparatus may not be ready for use

b)There may not be an apparent relation between the demonstration experiment and

the topic under discussion.

c)Black board summary not up to the mark

d)Teacher may be in a hurry to arrive at a generalisation without allowing students

to arrive at a generalisation from facts.

e)Teacher may take to talking too much which will mar the enthusiasm of the

students.

f)Teacher may not have allowed sufficient time for recording of data.

g)Teacher may fail to ask the right type of questions

a)It is an economical method as compared to a purely student centered method

b)It is a psychological method and students take active interest in the teaching learning process

c)It leads the students from concrete to abstract situations

d)It is suitable method if the apparatus to be handled is costly and sensitive. Such apparatus is likely to be handled and damaged by the students.

e)This method is safe if the experiment is dangerous.

f)In comparison to Heuristic, Project method it is time saving but purely Lecture method is too lengthy

g)It can be successfully used for all types of students

h)It improves the observational and reasoning sills of the students

a)It provides no scope for "Learning by Doing" for the Students as students are only observing the Teacher performing.

b)Since Teacher performs the experiment at his/ her own pace many students may not be able to comprehend the concept being clarified.

c)Since this method is not child centred it makes no provision for individual differences, all types of students including slow learners and genius have to proceed with the same speed.

d)It fails to develop laboratory skills in the students.

e)It fails to impart training in scientific attitude. In this method students many a times fail to observe many finer details of the apparatus used because they observe it from a distance.