Bungee Jumping Barbee uses a Barbie doll and rubber bands to simulate a bungee jump. Several rubber bands are attached end to end to make the bungee cord, and then the cord is attached to the feet of a Barbie doll. The Doll is then placed upright on a horizontal meter stick and allowed to fall, being sure that the other end of the rubber band cord is looped around the meter stick. The amount the rubber bands stretch on the first bounce is noted as well as the number of rubber bands in the cord.

Skills addressed in this activity:

• Graphing methods
• Predicting data and estimating for conditions not tested
• Measuring length of rubber band cord
• Extrapolation beyond measured points
• Behavior of rubber bands as an example of kinetic and potential energy

extrapolation

estimation

kinetic and potential energy

Materials:

• meter sticks, 3
• Barbie doll
• Rubber bands
• Graph paper

Procedure:

1. Find a suitable Drop Zone, such as a stair well for three floors, for the final jump.
2. Locate a spot in the room such as the top of a cupboard from which to have the Barbie fall for data collection. Put the meter stick horizontally on the top of the cupboard so the end sticks out beyond the edge of the cupboard.
3. Attach about 4 rubber bands end to end to make the bungee cord. Attach one end of the cord to the feet of Barbie. Let Barbie fall and measure how far she falls on the first fall. Measure the length of the rubber bands without Barbie.
4. Add another rubber band or two and repeat. Measure 10 different data points. Graph the length of the fall on the y axis versus the number of rubber bands on the x axis. Connect the points.
5. Extrapolate the graph to find the number of rubber bands for the official Drop Zone. Make the new, longer, real bungee cord. Drop Barbie at the Drop Zone.

After all the groups have dropped their Barbies, the results may be announced. A short break may be taken to allow students to make small adjustments. Then the students may have a second chance to drop Barbie.

Students should work in groups, 3-4 per group. When testing at the Drop Zone, have one group at a time bungee jump the Barbie. Assign one student to drop the Barbie at the top of the stair well and three other students to observe the drop at the bottom. One student should hold up a meter stick, one student watch carefully to judge how close to the floor the Barbie falls, and one student to record the measurements. In case Barbie does not stop before hitting the floor, place a blanket on the floor to cushion the fall, and prevent Suicide Barbie. For the graph, be sure that the paper has small enough squares so there will be enough squares for the extrapolation. There will be a number of ways that students can extend the line to find the number of rubber bands for the Drop Zone.

Students should enter the data from the Drop Zone onto their graphs. Are there surprises? Does everything happen as expected? Several topics of discussion:

• Accuracy of graph
• Accuracy of extrapolation
• Data collection techniques
• Is the graph linear?
• Barbie versus reality
• To jump or not to jump - trust the math or not?

Possible errors can be discussed.