1)  Measure is the length of the string that the plane will be hanging from with a meter stick

2)  Measure the plane's mass with a scale to the nearest tenth of a gram

3)  Hang the plane and turn it on, giving it a throw to get it going. Wait until the plane looks like it is no longer changing its vertical position (this should take about 30 seconds)

4)  With the plane at equilibrium in the y direction, have one student grab the plane and be careful to not move it in the vertical direction. Then measure the vertical distance from where the plane is to the vertical level at which it is anchored with a meter stick. Repeat the process again, and gather another data point.