This is fabulous home made rocket using a plastic drink bottle
Pump air in with a bike pump and increase the air pressure inside the bottle. Finally, the pressure is high enough for the rocket to take off, firing water out of it’s mouth and streaking up into the sky. This rocket can go 10-20 meters off the ground. It’s serious.
BEWARE: This rocket is quite powerful. Make sure you have an adult around to supervise.
You need:
- A plastic (PET) bottle (empty soft drink bottle – any size)
- A bike pump
- A needle to pump up a basketball OR a bike valve (cut it from an old bike tyre).
- A rubber stopper (that fits the mouth of the bottle)
- Tie wire or coathanger wire (OR thick cardboard)
- Straw
- Strong sticky tape
- Pliers, Wire cutter
- Water
There are two types of launch pads you can make:
Launch Pad Type 2 |
Launch Pad Type 1 |
What to do
Make your rocket launch pad:
This is the trickiest part. You need to make something sturdy enough to keep the rocket standing up straight, about 5 – 10cm off the ground. The fins or the stand must hold the rocket high enough off the ground for the pump to attach underneath.
Type 1: Use cardboard cutouts of fins, attached to the bottle with sticky tape. (The fins will travel up with the rocket when it launches.)
Type 2: fold a wire into a stand. OR make a stand out of an upside down icecream bucket with a hole in the top for the bottle. (These stands stay on the ground while the bottle flies up.)
a) Stopper with bike pump valve | b) Stopper with ball pump needle |
To set your rocket up
- Fill the bottle about one third full of water.
- Push the rubber stopper into the mouth of the bottle firmly.
- There are two ways to attach the pump:
- a. Drill a hole through the stopper, and glue a bike valve over the hole. OR b. Poke the bike pump needle through the rubber stopper. It must be a tight fit. Place your bottle-rocket the right way up on its stand (with the bottle upside down)!
To launch your rocket
- Pump air into the bottle.
- Keep pumping. Sooner or later the rocket will take off! (You get no warning. Don’t EVER lean over the rocket!).
Why it works
Air fills the bottle-rocket as you pump. As you squash more and more air into the bottle the pressure increases. Eventually the air pressure will be strong enough to push the rubber stopper out.
When the rubber stopper is forced out, the air pushes the water out too.
As the rubber, water and air come out the bottom of the bottle, the bottle is pushed in the opposite direction. When the rubber-water-air-mix goes down, the bottle-rocket goes up! Because the bottle-rocket doesn’t weigh very much it goes a long way up. We put water in the bottle because water is much heavier than air. So the rocket will go further.
Why it doesn’t work
Everything depends on getting a good seal with the rubber stopper. If the rubber stopper doesn’t fit tight enough, water will leak out when you pump. Or the bottle will fly off too early and not go far.
- When nothing happens: Look for air bubbles when you pump. You should see air bubbling in. Your pump may not work, or it may leak air out before it gets to the bottle.
- When your bottle doesn’t go far: You may have the wrong amount of water in the bottle. Try with more or less water
hi this web site is really good esspesially if you are working on how to power homemade rockets could you send me some other ways to power rockets? or is this the only way? my class are talking about something like bicarbonite of soda and viniger or diet coke and a mometntos sweet but dont if it will work
thanks
hope to hear from you soon
alys:-)
—-Sorry Alys, I ony just saw your comment (3 weeks later). I hope you had fun with the bicarb and vinegar. — Jo
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This is a Nice Site, thank you
you’ve helped me a lot, now i can have fun 🙂
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thanks it really helped a lot. It worked on the first try
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Well after seeing Anna Rose’s interrogation of David in your kitchen I’m glad to see that David Evans is married to a real rocket scientist 🙂
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Thank you. Been looking for something easy to do with summer camp kids coming soon. Children going into 1st grade. I’ll have them decorate their own bottles and I’ll shot them up. Thanks again.
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Hi Jo
Any chance you could re-link these images in the science-activities/bottle-rocket/ post.
I am curious as to how you used the valve.
I have a 6yo who is fascinated by rockets and thought we could try this this weekend.
Thanks
REPLY I will try to get it right for you! – Jo
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Fixed! Thanks for letting me know.
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IT WORK!!!!!!!!!!!!!!!!!
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thanks
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[…] can find pretty simple DIY instructions to make you own at home on this site, or a really hard-core version from […]
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Cool
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