These easy squeezy bottle rockets are great fun to make and a brilliant introduction to forces, in particular Newton’s Third Law of motion, which sounds complicated but actually makes a lot of sense.
Newton’s Third Law
For every action there is always an opposite and equal reaction.
Think about a space rocket taking off. The rocket’s action is to push down on the ground with the force of it’s engines, the equal upwards force pushes the rocket up or if you think about air coming out of a balloon, the air is being forced downwards yet the balloon flies upwards.
In the case of our squeezy bottle rockets, as you squeeze the bottle, air is forced out of the straw and pushes against whatever you have sealing the top of the larger straw, this force causes the straw to “fly” through the air.
How to make a squeezy bottle rocket
- Empty Squeezy water bottles
- Blue tack
To build a mini rocket which can be launched from the water bottle.
For the bottle
Lift up the sports cap and push in half a straw, seal around it with blu tack.
Squeeze the bottle and make sure air is coming out of the top of the straw, not the sides.
For the rocket
Draw and cut out a cardboard rocket.
Seal one end of a larger straw than the one in the bottle with sellotape.
Attach the rocket onto one side of the straw.
Place the rocket on the bottle and squeeze the bottle hard, the rocket should fly into the air.
Squeezy sauce bottles can be used instead of water bottles to make this activity a little easier.
What happens if the rocket is made bigger/heavier, does it fly as far?
How do you think using a smaller bottle will affect how the rocket flies?
When experimenting remember to only change one factor at once, so either change the size of the bottle or the weight of the rocker, not both!
Key Stage 1 Working Scientifically
Key Stage 2 – Forces/Working Scientifically