Raw Egg Bungee Experiment

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:                                                                    R2 VALUE:

  • Even with the variability in rubber bands and possible measurement inconsistencies, using the r2 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.