Encouraged by the great success we had with NASA's paper rocket plans we decided to give their rocket car project a go.
We are revving up to start on the STEAM Club project for the Oxford Kinetics Festival, which will be one large Rube Goldberg set-up. It seemed like a rocket car might be a good component that might be able to be added to this future work.
There was some rough going with the rocket cars. The propulsion came from the air leaving a balloon which had to be attached to the vehicle. We used drinking straws as a means of inflating the balloon. Most of the consternation centered around axles and wheels. Kids had a lot of trouble finding the right combination to get the cars to really move along the way they hoped. Decisions had to be made as to whether you wanted fixed axles and rotating wheels, or fixed wheels and spinning axles. Overall the fixed wheels seemed to work best. Most success came from using a part of a drinking straw attached to the underside of the craft. Then a small dowel could be set inside the straw and used as the axle; wheels could then be fixed to the axle.
We laid down a very long strip of duct tape down the hall to track distances so kids can compete against each other and against their own previous iterations. I think this could be a successful project with some pre-implementation trials of materials. We try to just source optional materials from the local hardware store or our weird collection of odds and ends. If you purchased actual wheels to use that fit securely on an axle that would make things easier but do away with some of the inventiveness. If kids can power through the frustration phase they can really find some innovative solutions. Connecting the balloons to the straws and finding suitable wheel options were problem areas.