HELP WITH THE BOUNCING BALL INVESTIGATION

You have till the last Saturday of term to get this finished and handed in to me.

Planning

• Make sure you have explained how you made sure it was a fair test.  Which factors did you vary?  Which did you keep constant?  {Be clear that this is not to do with experimental accuracy, repeating, and so on...}
• You need a clear prediction, preferably not just a vague "if this increases, then that will increase" sort of prediction.  A graph makes a good prediction.  Suggesting that something remains constant makes a nice clear prediction. 
• Theory: Explain what you think is happening, using your wide knowledge of physics ...   Draw diagrams.  Give other examples.  Talk about mechanical energy transforming to heat.  Draw a flow diagram showing the energy conversion.  Why is heat being generated (Consider what is happening to the atoms in the material of the ball)?

Observing

• You need repeats of the data.  Remember to put units on the headings of the columns.

• You can use a table-tennis ball as well as - or instead of - the bouncy rubber ball.  Obviously the efficiency of bounce at a particular height may be different.  Furthermore, the way this efficiency changes on your graph as the height changes may be different.  You can plot two kinds of ball onto the same graph, for an interesting comparison.

• If you have discussed the rubber hysteresis loop as part of your theory, you might like to add weights to stretch (quite a long way, to get beyond Hooke's law) an elastic band, and then remove the weights to unstretch it, and hence plot the hysteresis loop you are discussing.

Analysing

• Show at least one complete sample calculation of efficiency.

• You can draw more than one best-fit line (trend line) onto the graph - and then discuss which one you think is more likely.

• Refer back to your prediction.  Does the data seem to support it, or not?

• Refer back to the theory.  Does it look as though it is correct?

Evaluating

• This is the hardest one.  You have decided what the trend shown by your data is.  But all your data points are not exactly on the trend-line.  Why not?  You need to explain carefully why it was not reasonable to expect this.  Discuss the experimental inaccuracies.

• You need a quite detailed description (at least half a page) of a further experiment that you could do, involving bouncing balls.  (This is not just an improved version of your experiment; it is a new one)