How do you build a rocket for a science fair?

Answer 1

Try a bottle rocket. Pumping air through the water the pressure inside the bottle builds up until the force of the air pushing on the water is enough to push a cork out of the end of the bottle. The water rushes out of the bottle in one direction whilst the bottle pushes away (takes off) in the other. This results in the bottle shooting upwards.

Method:-What you need is an empty plastic bottle (i.e. coke soda bottle)

cardboard made into a cone and 4 fins, a cork, a Tyre pump or similar with a needle adaptor'

water.

Push the needle adaptor of the pump through the cork, it needs to go all the way through so you might have to trim the cork a little. Then decorate the bottle with the cone and fins in a colour of the school for instance or even teams if you want to make a team event.

Fill the bottle one quarter full of water and push the cork in tightly.Now, take the bottle (make sure your out side a building and away from people and connect the pump to the needle adaptor. ) Make sure the fins will hold the bottles weight if you make some strong fins it should stand up by itself.

Pump air into the bottle, making sure all spectators stand back, the bottle will lift off with force after a few seconds.

It's not as impressive as a real fueled rocket but its safer, costs less and can be recharged with water for another go at launching it. It you want a greater effect of course you can select a larger plastic container (here we used a 1 ltr bottle).