Plan and execute an investigation into the energy changes of a table tennis ball in terms of the energy changes that occurs when it bounces on a rigid surface.

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Andrew Dhushantha

                                Physics Coursework

                                 

               Planning Experimental Procedures and Obtaining Evidence

Aim:

        To plan and execute an investigation into the energy changes of a table tennis ball in terms of the energy changes that occurs when it bounces on a rigid surface.

Equipment:

        To conduct this experiment the following equipment will be required:  two-metre rule, clamp, boss, stand, and ping-pong ball.

Diagram:

 (DIAGRAM)  - cant email diagrams – too much bytes

Method:

        First of all the equipment is assembled as shown in the diagram above. The ping-pong ball is dropped from two metres above the ground. It is dropped from here, as this is where air resistance starts to be tested, I know this through the result of my pliminary experiment. When dropping the ball the first time you must be careful to measure exactly two metres from ground level. When dropping the ball from two metres, the bottom of the ball must be at two metres above the ground. You must look at the bottom of the ball with your eyes being at the same level as the bottom of the ball. This is done to obtain very accurate results.

        Next drop the ball from the desired height, first record the general height of the bounce of the ball. When dropping the ball be careful not to push downwards as this will disorientate your results. Then when the ball is bounced again we can record the bounce height more accurately, again when measuring the bounce height, make sure your eyes are at the same level as the ball. This will prevent the ball from appearing lower or higher than it really is. The first estimated recording is used to find what region to bounce gets up to also allows us to be at eye-level to the maximum height of the bounce and therefore acquire a better more accurate reading.

        This processes is repeated continuously as the ball is dropped from 10 cm lower each time. Eventually we obtain 20 results, ranging from 200cm to 0cm. We will repeat this process so that we obtain 3 sets of results so that we could use the average of these results to draw up a graph. Using this data we plotted a graph, we then drew a best-fit line for this graph. If any anomalies were spotted for certain heights, a second reading or even a third for that height was acquired. I dropped the ball from each height 3 times getting very accurate results in the first place. I took the mean of the 3 heights and rounded it up or down to the nearest centimetre. This will provide us with more accurate and reliable results. During the experiment the temperature, surface and the ball used will remain constant to make this a fair test.

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Prediction:

        I predict that the ping-pong ball will not bounce as high up as it was when originally dropped. I predict so because I do not think the ping-pong ball bouncing on a laboratory floor is very efficient (50% - 80%). Lots of energy is lost as heat or sound. Since a ping-pong ball is being used, when dropped from higher distances more energy is lost due to the force of air resistance. Considering this factor I predict that the ping-pong ball will bounce more efficiently as it is dropped closer to the ground.

        I also can predict ...

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