I have found this cool project on Home Science Tools  and was really pumped to share this with the Cub Scouts for which I am the new Cubmaster. Here’s a quick step by step for how to build a balloon powered rocket car.

First off we need a plastic water or soda bottle (500ml or 16.9 oz depending on your favorite measurement system).

You will also need 5 beverage straws, one wooden shish-kabob skewer, 4 water bottle caps (wheels), a balloon, and duct or masking tape.

Tools will be a nail, hammer, knife, and scissors.

First step is to cut one beverage straw into two bottle width lengths.

Second step is to use a hammer and small nail to put the hole in the wheels (bottle caps).

Make sure the nail is a bit narrower than the skewer.  If it is not, you will need some modeling clay, or some form of glue to adhere the wheel to the axle (skewer).

 

After putting one wheel on each axle, you will then attach the cut straws on the bottom of the bottle and attach the other wheel on each axle.

 

Following this, you will then stretch out the balloon a bit, by pulling it, and then inflating/deflating the balloon several times to prepare it.

After doing this, you will insert four straws into the balloon and then tape them together.

 

After this you will cut a small x in the bottle about 4 inches from the mouth of the bottle and then insert the straws from the cut through the mouth.

 

You will then blow into the straw, between breaths pinch the balloon above the straws to seal it and let you inflate another breath into the balloon.

After it is full, set it on a hard surface and let her go.  She should move along the ground powered by the air from the nozzle you built with the straws and the balloon.

Your rocket can be decorated with stickers, paint, or other light weight objects.

Send me pictures of what you have made here