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

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

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

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

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

Readings presented appropriately Sig Fig 70.0cm 700mm 0.700m for drop height Rebound height is more difficult:- Either nearest mm or nearest cm would be accepted

Calculating means should also be included in your results table

Graph s/cm h/cm

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

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

Use of set square-checking for vertical

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)

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

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

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

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)