Did you know you can make and launch a water bottle rocket using just a plastic bottle, water, cork, needle adaptor and pump?
How to make a Bottle Rocket
How do water bottle rockets work?
As you pump air into the bottle the pressure inside the bottle builds up until the force of the air pushing on the water is enough to force the cork out of the end of the bottle. The water rushes out of the bottle in one direction whilst the bottle pushes back in the other. This results in the bottle shooting upwards.
What you need to make a bottle rocket
- an empty plastic bottle
- cardboard made into a cone and 4 fins
- a cork
- a pump with a needle adaptor
- water
You can buy a kit with the parts except from from the pump and the bottle – please check the contents before buying
Instructions – how to make a bottle rocket
- 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 bit.
- Decorate the bottle with the cone and fins.
- Fill the bottle one-quarter full of water and push the cork in tightly.
- Take the bottle outside and connect the pump to the needle adaptor. Ours wouldn’t stand up on the fins so we rested it on a box, but 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.
Warning!
Please make sure an adult is around as the rocket takes off very suddenly and forcefully as you can see in this video clip. Do not approach the rocket once you have started pumping even if it looks like nothing is happening.
Why does the water bottle rocket launch?
As you pump air into the bottle pressure builds up inside. If you keep pumping, the force of the air pushing on the water eventually becomes strong enough to force the cork out of the bottle allowing water to rush out in one direction while the bottle pushes back in the other direction. This forces the rocket upwards.
Space rockets work in a similar way to the bottle, but instead of squirting water, they burn fuel to make a powerful jet of hot gas. The force of the gas downwards pushes the rocket upwards. This is a great demonstration of Newton’s Third Law.
What is Newton’s Third Law?
Newton’s Third Law says:
‘for every action there is an equal and opposite reaction’
Who was Issac Newton?
Issac Newton was an English scientist most famous for his theory of gravity, but he also worked out three laws of motion to describe how objects move. You can find out more about the Three Laws of Motion in my book, This Is Rocket Science which has lots of activities to demonstrate all three laws based around rockets and space.
More Rocket Experiments
Find out how to make a rocket mouse
Make a film canister rocket
Try one of these other easy air pressure experiments, including making a fake lung, a barometer and a coin popper!
Can you show a friend how to make a bottle rocket?
This Is Rocket Science – Space Experiments for Kids
For more fun rocket science activities check out our new book This Is Rocket Science
Affiliate links
Images taken from This Is Rocket Science
Last Updated on May 11, 2023 by Emma Vanstone
What a lovely project! We’ll give it a go too, thanks for sharing:)
Oh WOW Emma and Kerry this is AWESOME!!! We will definitely be trying this amazing experiment out …. all for the children’s benefit of course (cough, cough).
Donna 🙂 🙂
I love stuff like this. My 7-year-old is our little scientist around here, and he is going to love this project!
It was brilliant! I’m so glad you liked it. 🙂
Thank you. We are very excited by it, and can’t wait to add to our growing collection of experiments!
Water rockets are soooo much fun, but just a little scary 🙂
It was quite scary! We were lucky it didn’t go out of the garden! x
yay, this is fabulous – how fun & educational! Thanks for sharing on the Sunday Showcase!
Thank you!
That looks awesome. I learned the hard way not to go near projects like that after I did……. That was an unpleasant chemical burn and took a few days to stop stinging.
I’ll have to see if we have a hand pump anywhere.
ouch, sounds painful! The rocket was fantastic though.
The little blue cone makes the rocket look so much more exciting!!!
This is a great experiment that I think any kid would enjoy! Thanks for sharing with Learning Laboratory at Mama Smiles 🙂
We used to do this…so fun!
its great and so easy!
WHAT FUN! My kids will love this.
Thank you, my children thought it was fantastic
Love love love this experiment! Such fun! And love the Science Sparks look!
Thank you for sharing on Kids Get Crafty! Great to see you there!
Maggy & Alissa
This looks so much fun I can remember making them with my physics class. J would also love it. I love the new look to science sparks.
Thank you for linking up to Tuesday Tots
This is so cool. I can’t wait to try this with my kids!
We loved it!
oh no. what happened?
WOAH! Look at that rocket go! Love this! I’ll be featuring this post as part of my Earth Day Activities for Kids: Upcycling roundup from the Weekly Kids Co-Op. xoxo P
oh wow, thank you.
Found this through the parent pin it party and love it we must try this
There is a little air leaking out when flip the bottle over. Is there a certain cork or needle I can use? Right as the bottle fills up with air it starts to leak. any advice would be appreciated.
Bob
Hi–what a fun craft! Would this work with different sized plastic bottles–such as a 16oz plastic soda bottle? Thanks!
This is a awesome experiment…
What size cork would be best to use for this project?
Not Very Good
I haven’t tryed it yet but I bet it will be cool
bottle rocket?
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Great work on engineering ,I will attempt the Rocket with my science club when schools open in January 2020.