Based on an experiment by Dr. Holly Hirst.
Bungee jumping looks pretty exciting. Today we will let you decide how
long to make the bungee cord for a fragile jumper -- a raw egg. The goal
is to make it exciting but not fatal for your jumper. A small prize
will be given to the group that gets closest to the ground without harming
their egg. There is only 1 egg per group.
The Experimental Stage Gather your data as follows:
Make 3 jumps each with 2, 3, 4, and 5 rubber bands from a height of 1
meter. You may wish to use a pen, and hold it perpendicular to the top of
the stick, so that you drop the egg sufficiently far away from the meter
stick.
Record how far the egg travels from the top of the
meter stick to the point closest to the ground (12 data points).
Be very careful with your egg - protect it from hitting anything
and make sure that it doesn't swing back and hit the meter stick.
Accuracy is important, so
the same person should drop the
egg each time, and the same person should be watching the meter
stick each trial.
Number of rubber bands
Distance dropped in centimeters
2
2
2
3
3
3
4
4
4
5
5
5
Excel and Data Analysis Enter the chart data into excel in 2 columns.
Click on the grey A box above the number of rubber bands data.
The column will become highlighted.
Click the shift (or similar) key, hold this down and then
then
click on the grey B box above the distance data so that
both columns will be highlighted. Under the Insert menu, release on
Chart.
Look for and click on XY (Scatter) and then on Marked Scatter.
Right
click on one of the points on your graph. Under the Chart menu
release on Add Trendline.
Click on Options and select the bottom two
options (Display equation on
chart and Display R-squared value on chart). Click on OK.
I'll come around and help!
Back on the chart, click on the equation of the line, so that you can read the
info.
REGRESSION LINE:
R^{2} VALUE:
Even with the variability in rubber bands and possible measurement
inconsistencies,
using the r^{2} value,
your number of rubber bands should be a very strong predictor of
the distance traveled because
he stretch ability and similarity of the
rubber bands shows a
constant slope for the change in
distance dropped / change in rubber bands.
EXACTLY what prediction of the number of rubber bands required
for 2.0 meters (200 cm) does the equation of the regression line give
(plug in for the y-value and solve for x)?
Next decide how many rubber bands you would like to add to the
5 you already have. I'll bring them to you. Add them and then bring egg
(in the bowl!) up to the front (don't test it now!).
Next work with your group members on
What Kind of Research Should Our Government Support?
until we come back together.