Hi Bob
An activity I did when I wa teaching was to design and build a rubber band racer. It’s kind of a take off on the “Pine Wood Derby” but a bit more advanced. The car had to be “Powered” by any non-metalic stretchy material ie, rubber band, elastic out of your underware, grandma’s corset, surgical tubing works great; leave it a bit open ended but stay away from metal springs and there will be fewer cuts and injuries.
Car had a size requirement: I gave them a 2 X 4×12” long. Some great looking dragsters were designed.
I showed them how to band saw off the sides like a band saw box, cut out the bottom for a slot to put the rubber band in, then glue the sides back on. Made a jig to sand the wheels nice and round, rubber bands off broccoli work great for tires traction, bottle caps for front wheels, soda straw thru car for bearings, rear wheels press fit to rear axle (3/8 dowel, little pin of 1/8 dowel on reaxle center to hold band, roll car in reverse to tighten…. you have the idea. Anybody that wants to get real creative and exotic…. bondo fairs out real nice with the end of a tongue depressor and will make a nice inside curve on fenders and pieces added on. Paint hides all sins. A lot of kids put on decals. Have a race day: we raced for fastest thru 20 feet, single elimination.
Was a lot of fun.
-- Islandwoodworker@Gmail.com