1. Task
Will involve the energy transfers involved when a
table tennis ball is dropped vertically and allowed
to bounce on a horizontal surface
Equipment provided for taking measurements
Metre rule for measuring heights-uncertainty
Set-square-to set in vertical position

2. Task
Will involve the energy transfers involved when a
table tennis ball is dropped vertically and allowed
to bounce on a horizontal surface
Height (dropped from),h
Height of rebound,s

3. Table and graph
Words or abbreviations
height/centimetre or
h/cm
at top of column
Height
(dropped from)
Height of
rebound

4. Results
Range of values to be between 100 and 10cm
(this includes the rebound heights)
This implies- preliminary tests to check rebound
height
Lowest height requires a rebound height above 10cm
Maximum height of 100cm – could be less
sensible intervals chosen
Minimum number of readings- to see a trend

5. Repeats
Repeats
Repeats
Repeats
Repeats
Rebound height should be measured at least
3 times for each height.

6. Readings presented appropriately
Sig Fig cm mm m for drop height
Rebound height is more difficult:-
Either nearest mm or nearest cm would be
accepted

7. Calculating means should also be included in your
results table

8. Graph
s/cm
h/cm

9. Line graph analysis
Proportional - straight line through the origin
Linear - a straight line (not through origin)

10. uncertainty in h uncertainty in s(rebound)
h will be + or – 1mm
Uncertainty in an averaged result
will be ½ x range of repeat values

11. Use of set square-checking for vertical

12. Use of set square- measuring diameter of ball
Uncertainty in A = + or – 1mm
Uncertainty in B = + or – 1mm
2 uncertainties for a distance added together
uncertainty in diameter =+ or – 2mm (or more)

13. Uncertainty in w + uncertainty in h
Change in gpe
height - diameter
Measured height
Gpe = w x h
uncertainty
will be
Uncert in w + uncert in h
Uncertainty will be:-
Uncertainty in w + uncertainty in h

14. Tricks with gradients
Well drawn
straight line
Lines can be
extended
If necessary
Smooth
curve

15. Gradient rules
Large triangle for linear part of graph
(extend line if necessary)
Correct readings taken
Gradient calculation:- 2 or 3 sig. fig
Correct unit must be stated

16. Does temperature affect the bounce using a
Larger ball?
How to measure temperature
Number of temperatures (8,9 or 10)
How to release the ball
Control variable -----height
Quick transfer from water reduces heat loss
Use tongs for hot temperatures to avoid burns
Better way to measure rebound height
(still frame analysis from video)
Repeat readings (reheating ball each time)