**Objective:** At the completion of this experiment, the students will be able to make an accurate prediction using the

equation of a trend

line created using real-world

data that they have collected themselves. They will then have the opportunity to test their prediction.

**Prior Knowledge:** Students should be able to write the

equation of a

line using the point-slope formula

*y = m(x – h) + k*

where m is the

slope of the

line and (h, k) is an

ordered pair on the line. The students should also be able to make a

scatter plot and

graph the

equation of a

line on the TI-83.

**Materials needed:** various size eggs (each group gets one, and only one egg)

a meter stick

rubber bands (each group will need 10 – 50 of the same size)

zippered sandwich bags

several stations around the room with 2 meter sticks taped end-to-end to the wall

graph paper

TI-83 calculator

a balcony or crosswalk at least 4 meters above the ground from which students will make their final egg drop

**Group size:** 3

**Procedure:**- Each group will get one egg, a sandwich bag and up to 7 rubber bands (depending on the size). Place the egg in the sandwich bag and make sure it is tightly sealed. Attach one end of the rubber band to the sandwich bag, and the other to the meter stick.

- Each group will begin the experiment by measuring the length of the drop of one rubber band. To do this, hold both the end of meter stick that the egg bag is attached to and the bottom of the egg at the top of one of the 2 meter heights. One person will drop the egg while the other 2 group members record how many centimeters the egg dropped. Repeat with one rubber band at least 3 times.

- Add another rubber band, drop at least 3 times and record the length of each drop. Continue this process, adding rubber bands and recording drop lengths, until the group feels there is sufficient data to make a scatter plot, draw a trend line, and write the equation of the trend line.

- Each group member should draw a scatter plot of the data, making sure that the independent variable is on the x-axis. Your axes should be appropriately scaled and labeled.

- Draw a trend line, pick 2 grid points that the line passes through (these may or may not be actual data points), and write the equation of the trend line.

- Enter the data into List One and List Two on your TI-83, and recreate the scatter plot on your calculator. Verify the accuracy of your trend line by entering the equation into your Y= screen and graphing it on your scatter plot.

- Once you are sure that you have the equation that best fits your data, your teacher will give you the final height from which you will be required to drop your egg. Use your equation to predict the number of rubber bands that will be needed to get your egg as close to the ground as possible without breaking it. Your teacher will probably require you to show your work in order to receive the rest of the rubber bands necessary for a successful egg drop.

- Add your predicted number of rubber bands to the ones you have already attached to your egg. Once the entire class is ready, your teacher will take you to the designated drop area. Each group will drop their egg once while the other groups are at the bottom to judge how close any non-broken eggs come to the ground.

- Survivors will have a few minutes to adjust the number of their rubber bands, and then will drop again. The teacher and other groups will determine the winners (the group whose egg comes the closest to the ground without hitting it).

Good luck – don’t make egg drop soup!