Almost Unschoolers: Building Balloon Powered Racers

Physics and engineering turn into boredom buster fun, when you design and build your own balloon powered racers. Best of all, they can be built with simple supplies, and recyclables found around the house.

We made our first racer out of a piece of a PopTart box, four milk caps, three bendy straws, a wooden skewer, some tape, and a balloon, with the use of a thumbtack, nail, and a pair of scissors.

First we used the thumbtack, and then the nail, to make holes in the centers of the milk caps.

We opened the PopTart box (any cereal type box would do), and cut out one of the side pieces.

The side of our box was bent a little, so we cut that part off, too.

We cut a hole in the middle, sort of closer to one end, than the other.

And, we cut the straight end of the straws, just slightly shorter than the width of the cardboard, and taped them on the bottom of the cardboard, as axles.

Then, we broke the tip off of the skewer, before breaking the skewer in half, and threading them through the straw axles, and sticking one of the milk cups on each of the sticks.

All that was left then, was to place the non-bendy ends of what was left of our straws into the balloon (two didn't seem to fill mouth of the balloon very well, so we shortened a third straw to match, and used it too).

We started out using masking tape, but switched to electrical tape, because it held tightly, without squishing the straws. I think clear tape would work fine, but we were out of that.

We taped the straws together into the balloon, and through the hole in the cardboard, pointing out, aiming slightly down, in the back of the car.

Our seal was not perfect around the mouth of the balloon, so to blow up the balloon, through the straws, we had to hold the mouth of the balloon firmly on the straws.

The younger children had some trouble holding the seal on the balloon (remember to keep an eye on younger children with uninflated balloons - they are choking hazards), so we added a clothes pin...

...that they could remove, after they set the car on the floor to let it go.

Of course, the children wanted a second car, so they could race, but we were all out of milk caps (I kicked myself pretty good, for the pile of the them I threw away recently). But, necessity is the mother of invention, so enter - the Lego and toilet paper tube, balloon racer.