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...bouncing balls - part 2...













• Be able to collect data about the bounce height of a table tennis ball.



• Be able to produce a scatter graph from your results.



• Be able to explain what you found, using scientific ideas to justify your conclusions.
















Task 1 - Peer assessment of homework tables





Think hard!





You designed a results table for homework.




Swap your results table with the person next to you. 




You are going to give their table a mark out of 5, using the criteria below.








Peer marking - rules for a good results table





1) Do all the columns have descriptive headings?


2) Do the columns have units in the header row?


3) Are there columns for repeat readings?


4) Is there a a column for the average?


5) Were the lines drawn using a pencil and ruler?




Award one mark for each criterion, up to a maximum of 5.  If the table scores less than 5, write a suggestion for how to improve.









Example results table





Your results table should look something like this:



There is a copy of the table you can print for students here, or a skeleton results table here.












Task 2 - Collecting data






You are going to collect data for your experiment.  You will need:





1 x metre ruler

1 x table tennis ball

Some blu-tack or sticky tape





Record each measurement in your results table.











Your experiment will look like this.















Task 3 - Graphing





Graphs.  Woop woop!





Calculate the average of the results for each drop height, and then draw a scatter graph of your data.



Follow the five points below to make sure you draw a good graph.








Rules for a good graph





• The independent variable goes on the x-axis.


• The dependent variable goes on the y-axis.


• Both axes should start at zero.


• The numbers should be evenly spaced, and go up in equal intervals.


• Both axes should have descriptive labels, and units.



When you have plotted your points, draw a straight line of best fit starting at the origin (0,0).











Task 4 - Conclusion





Think hard!




Explain how your independent and dependent variables were connected.



1) Is the bounce height bigger or smaller than the drop height?

Explain why, using ideas about energy.



2) Did increasing the drop height make the bounce height bigger or smaller?

Explain why this happened, using scientific ideas about energy.



3) What kind of relationship does the graph show?  Is it linear?  Is it proportional?



4) Can you extrapolate or interpolate to gain any additional information from your graph?



Your teacher will tell you which questions to think about.












Task 5 - Something to think about




Think hard!

I know!  Me!




Could the ball ever bounce back to the same height it was dropped from?




Could the bounce height ever be higher than the drop height?




Think about energy to help you come up with an answer!  What would be different if the ball was thrown instead of dropped?










Hip-hoppity pop!




Think hard!




This is a Hip Hop Popper The bounce height is greater than the drop height!



This hip hop popper is angry.




How can this work?!  Think about the types of energy involved.



















Write an evaluation of your experiment.



1) How scattered was your data?



2) What does the amount of scatter tell you about the quality and repeatability of your results?



3) Were there any anomalies?  What could have caused these?



4) How could you improve or extend your investigation if you did it again?