Step 3: But I Want to Build a REAL Rocket!
Back to Newton again, and an important point: at no point does Newton mention size. He doesn't say 'throw loads of stuff out the back of a big thing to go forwards', he just says 'throw stuff out the back to go forwards'. It doesn't have to be tonnes of liquid hydrogen and oxygen, a matchstick will do. This really is rocket science on the cheap.
Just a Match?
Yes, just a match. The head of a match is a mix of chemicals that act as fuel and oxidiser, allowing the whole thing to burn rapidly and generate a lot of gas. If you can contain this gas and let it our through a small hole, you will get a jet of gas that is fast enough to launch your rocket, as long as you keep the rocket light.
Time to Build Yet Another Rocket
This is important: if you are going to make a rocket, you must be aware of the dangers. You are playing with fire, here, in every sense of the phrase. You will have very hot objects whizzing around the room. This presents a fire risk. If you are not a responsible adult, you must have one present when you attempt matchstick rocketry. You have been warned.
It is strongly advised that you have some form of fire-control to hand. Suitable methods are containers of sand or water, wet cloths or a properly-designed fire blanket or extinguisher. Remember not to use water-based extinguishers near electrical appliances.
Building a rocket isn't as hard as it sounds, but we will need some specialist items:
> Some matches
> Some aluminium kitchen foil
> Two paperclips (one will be a tool to build your rockets, the other becomes the launch-pad).
> You may also need a piece of Blu Tac, modelling clay or sticky-tape to hold your launch-pad down.
> A fire-proof surface to launch from (baking trays are ideal, but ask before you use them).
> Safety goggles are also a very good idea, as matchstick rockets can fly off in unpredictable directions - even in curves or spirals.
Start by straightening out one of the paperclips. With a pair of strong scissors or cheap wire-cutters, snip the head off the match.
Cut a square of kitchen foil, about four or five centimetres square (the exact dimensions you eventually settle on will depend a lot on skill and personal preference.
Look at your foil, and mentally divide it into quarters. Lay the match-head in the centre of the top-left quarter.
Now lay your straightened clip on the foil, one end touching the match-head, the other end passing down the middle of the bottom-left quarter of the foil and sticking out past the edge of the foil. When you remove the clip later, it will leave behind a channel or tube for the gases to travel along.
Carefully fold the left-hand edge of the foil over towards the right, creasing along the line of the paperclip and match-head. Make sure you keep the end of the paperclip touching the match-head, otherwise the gases will not be able to escape.
Fold the foil again, lifting the left-hand edge and creasing along the original edge of the foil. Fold again and again until you run out of foil. You should now have a long rectangle of folded foil, with the lump of the match-head about one quarter of the way along from one end, and the paperclip poking out from the other end.
Gently twist the foil along the length of the paperclip, forming a tube, and on the other side of the match-head, forming a point. Make sure that the pointed end (which will be the front of the rocket) is twisted tightly enough to seal the gases in, and make sure that the foil wrapped around the paperclip (which is now the rocket's nozzle) is a slightly snug fit (it should slide easily on and off the clip). Your rocket is now finished.
Launching Matchstick Rockets
Matchstick rockets are very light, and completely at the mercy of the slightest breeze, so they are definitely an indoor missile. Just be very careful about the flammability of the suroundings. Sofas and matchstick rockets mix a little too well!
Every launch needs a launchpad. Ours is made from the second paperclip. Look at the clip. Did you notice that it is made of four straight sections, joined by curves? Open up the clip slightly so that three of the straight sections form a triangle. Lay the triangle flat on the fire-proof tray, and bend the fourth section up so that it points upwards into the air at about 45Ã�??Ã�?Ã�Â°. Use the optional equipment to hold the clip to the tray.
Slip the rocket off the straightened paperclip and onto the launchpad paperclip.
Put your goggles on and tie any loose hair back.
Take a second match, light it, and hold the flame under the lump of the rocket that holds the match head. After a few seconds, the heat of the lit match will ignite the match head. The flame and hot gases will (hopefully) rush out of the rocket nozzle, propelling the rocket into the air.
This is the dodgy time, though. Your rocket could shoot metres across the room, fizzle on the pad, or shoot off sideways in a random flight. If you do not use enough foil, the motor (the match head) could burn out through the side. Too much foil, and it will be too heavy to go far.
Recovering the Matchstick Rockets
Let's be honest; many of your matchstick rockets won't need much effort to recover. You will need to be careful, though, as they will be hot. If you need to pick them up quickly, use tweezers, tongs or a clothes peg. If you don't want to squash them, leave them to cool for a couple of minutes. You must watch every flight carefully, as parts of the match-head can fly off in a different direction to the rest of the rocket.
Improving the Matchstick Rocket
There is always room for improvement in matchstick rocketry. Practice is the best way to improve your rockets, but you may also wish to experiment with the actual design;
Change the way you twist the rocket nozzle; leaving the last part flat to act as a tail can improve the flight.
Change the dimensions of the rocket - does it fly best with a longer or shorter nozzle? What about the amount of foil in front of the match-head, or the amount of foil in the whole rocket?
Try altering the fuel supply - can you make a rocket using two match-heads, or with the fuel alone (chipped carefully off the match)? Do different kinds of match make better rocket fuel?