Cosmo's Balloon Rocket Blast Off!

Hey fellow aspiring astronauts, it’s your mate Cosmo here!

So, you want to go exploring planets and stars!? Maybe you’ve picked up an alien distress signal you need to respond to...well, if you want to get out there we need to learn the clever clever science behind how a rocket gets off the ground here on Earth, up into the sky, and out into the vastness of space! DON’T WORRY this is science even I can understand so you’ll pick it up no problem I’m sure :)

I’ve got an activity here to help us learn, it’s easy, educational AND fun!

Here’s what you’ll need:

  • 1 Straw

  • 1 Balloon (The big round ones work but the long tube shape, like I’ve got in the picture, work the best)

  • 1 Peg

  • A nice long bit of string (the smoother the better, it could be wire or kite string if you’ve got it!)

  • Some tape

Now first of all, you’ll no doubt have noticed my very nice looking rocket there too!

It’s completely up to you how you want to design yours, use your imagination and come up with any shape you think would fly best, you can colour it in however you like too, just make sure it’s not too much bigger than your straw!

(I’ve used a nice picture of me and Carrie in Rocket 3 from the Let’s Go to Space activity book but you get to choose what rocket you’d make, what features it would have, and who’s flying it with you! Be super duper creative!)

Hold onto your rocket for later, and maybe ask an adult to help you cut it out ready for take off once the preparations are in place...and for the preparations you’ll need to start with your straw and string.

Feed one end of the string through the straw (it can be a bit fiddly but you’ll get there!) so now your straw is on the string. It should move quite easily up and down the string for the best take off!

Now, keeping your straw on the string, tie each end to some secure points in a room, or outside, but keep it nice and tight in a long straight line. Maybe see if an adult can help you (or someone tall-ish, you might be the tallest in your house!) fasten one end high up and the other a bit lower down for a proper rocket take off! (You can experiment with the angle of the string too, how will it affect your rocket travel?)

Blow up your balloon but don’t tie it! Use the peg to stop the air getting out...for now!

Now attach the inflated balloon to the straw with two bits of tape, just like I’ve shown you in the picture there.

Now’s the time to prepare your rocket for take off! Use a little more tape to stick your rocket onto the straw. Put on your helmets, get all your space exploring gear ready and strap yourselves in for the launch!

Here we go...start the countdown and when you’re ready remove the peg to watch your rocket fly...3...2...1...BLAST OFF!

Now here’s the science-y bit! A very clever chap called Isaac Newton discovered that with every action there is an equal and opposite reaction, fancy words I know, but this means that when our balloon, all filled with air, tries to return to the flat floppy shape it used to be, it pushes all the air out again! This creates a motion called THRUST which is a push created by energy. Thrust pushes our rocket along the string!

Our rockets are nice and light so don’t need much thrust to get them moving but with proper space rockets they’re much bigger, much heavier, and have loads further to go so they need lots and lots more thrust. They use thrust created from burning rocket fuel in the rocket engines, the blast energy pushes DOWN on the earth, to launch the rocket UP into space!

So so so so so clever! Enjoy playing, exploring and learning with this activity...we’ll be astronauts before we know it!

(There's a bit of a spoiler video below to show you what this experiment looks like in SLOW MOTION! But if you're about to make a rocket of your own maaaybe hold off watching for now so you can get the most excitement out of your launch!)