How high will your squeezy bottle rocket fly?

What to do:

1. Take the tube end of the snorkel and loosely wrap one sheet of paper around it. Tape the wrapped paper to itself so that it stays in a tube shape, even when you let it go. The paper should be loose enough so that you can easily remove it from the snorkel, but not so loose that it can fall right over the mouthpiece end.
2. Remove the tube of paper from the snorkel and fold over one of the open ends of the paper tube and tape it into place.
3. Now repeat steps 1 and 2 using as many different types of paper you want to. Try shiny ones, thin ones, thick ones, green ones, rainbow ones, invisible ones; the choice is yours. Once you have made these paper tubes, set them aside - they are going to be your rockets - but first we've got to make the rocket launcher!
4. Take the snorkel and with an adult's help carefully cut off the mouth piece.
5. Insert this freshly cut end of the snorkel into the opening of the plastic bottle until it is far enough in so it does not easily fall out. If it doesn't quite fit cut a little more of the snorkel off, or perhaps cut a small slit into it, this will make it easier to put inside the bottle neck.
6. Secure the snorkel in place with lots of sticky tape making sure that the seal is as airtight as possible. Now your launcher is ready.
7. Slide one of the paper tubes (the ones you made earlier) on to the snorkel and, while a friend holds the bottle in place, stamp on the bottle (be careful that's the bottle - not your friend's fingers!) and watch your rocket fly.
8. Once you've practiced a bit with your launcher, you could have a competition with your friend. Take it in turns to fire the rockets. Try all the different rockets you made. Which one works best? You could even get your Lab Rats to hold the string as a highjump, and see who can get their rocket the highest.

This is all about forces and friction. When you stamp on the bottle you push all the air that is inside the bottle closer together. The air then tries to escape out of the snorkel, but is blocked by the rocket. So instead the air fills the rocket, and then pushes down, out of the base of the rocket towards the ground. According to Blast Lab all-time hero, Sir Isaac Newton, if there is a push down, then there is also a push up, and it's this upwards push that sends the rocket flying through the air.

The friction part comes in, when you have to choose the rocket to use. The smoother the paper, the less friction there will be between it and the launcher. This means the rockets made of the smoothest paper should be easier to fire and go further.