You will need:

What to do:

1. Cut the string to the right length, but don’t tie it yet!

2. Cut your straw in half.

3. Thread the two bits of straw onto the string and then tie the string to two secure points somewhere in the room. When you tie it make sure the there’s a little bit of tension in the string.

4. Cut two short lengths of tape and place the middle of them on each bit of straw. These will hold the balloon in place.

5. Blow up the balloon, but don’t tie it off. Hold the end closed with one hand, or use a clothes peg, and stick it to your two bits of straw (get a helper for this bit if required).

6. Start your countdown and let go when you reach zero. We have liftoff!