CAUTION: this topic uses latex balloons.
Toy cars have a special appeal for children, and when they move, whatever their means of power, they hold people's attention. In this project, children build cars from cardboard and make them move using inflated balloons. Children are both surprised and fascinated that an inflated balloon can propel a car. Both the making of the balloon-powered car and its resulting movement can be highly motivating.
The skills required to construct a model car and the procedures for using a balloon as a means of propulsion are challenging ones for younger children. With some practice, they can achieve satisfying results.
The activities in Balloon-Powered Cars have been sequenced to let the children master different parts of the overall challenge rather than taking on all of the different problems at once. Therefore, in the first activity they only work on the problem of making a car without attaching a balloon. This allows them to focus on the goal of building a smoothly running car. Then they are introduced to only one kind of balloon, a 9-inch round one, instead of dealing with the several different sizes and shapes that are available. Different sizes are introduced later after they have mastered the problems of mounting and launching the 9-inch balloon. You will have to judge when to move on to each new activity depending on the skill level and interests of your children.