Spandex Gravity Well (+instructions to make your own!)

THIS VIDEO IS INTENDED FOR INSTRUCTIONAL USE. Please consult a physics teacher for a more complete explanation. Instructions to make your own gravity well are given below!
Objects in this demo will fall into the center of mass because of friction between the objects and the spandex. In the vacuum of space, objects would remain in orbit, following the applicable physical laws of motion.
Instructions to make your own:
- 3/4 inch diameter PVC tubing with 1/8 inch thick walls. Usually comes in 100 foot coil for ~$12-$30 (find at local hardware store).
To create a 60 inch diameter hoop, you'll want to cut a 188.5 inch length of tube. You can cut the tube with a PVC pipe cutter or hack saw. Slowly expand to full circle. You can use a heat gun or hair dryer to aid the process. Tape ends together. You can also connect the pipes with an inside PVC connector for less than $1.
- 60x60 inch spandex fabric (as stretchy as you can find 15-20% spandex content). 60 inches is the typical width of a spandex bolt. Get a little extra just in case. Usually fabric stores have coupons for 40-50% off a single item ~$10-$20.
- 12 large binder clips ~$5-$12, found at most stores.
Clip spandex to PVC pipe, stretching to keep spandex tight. Readjust as necessary.
Use chairs, stools, or tables to hold up completed gravity well. A more sturdy structure made of PVC pipe can be easily constructed.
For central mass, a 2 pound weight toning ball works well ~$5, found at most big box stores.
Marbles work well for test particles ~$5 at Toys-R-Us.