1x piece of flat wood - 50 x 20, though most sizes work
3x nails - about 2.5 inches (6cm) long, the kind with a flat head work better
5x rubber bands, or however many work for you
'ammo' (pegs work well, especially wooden ones)
1x piece of string, ribbon or other material - 10cm or more
1x magnifying glass - optional fun
1x pair of scissors
Cut wood to desired length, this can depend on what type you want, though 50 by 20 works well.
Get the wood, hammer and the nails.
Put two nails at the top of the piece of wood. Each nails should have about 5cm on each corner.
Put a nail at the bottom of the piece of wood. This nail should be about 5cm in from the bottom of the piece of wood.
Get the rubber bands. String them together and place each end rubber band around the top two nails.
Get the string/ribbon/wool etc and tie a loop around the middle of the rubber band chain. Pull the rubber band down towards the bottom nail and tie the string/ribbon/wool etc around the bottom nail. This should be done with care not to let the rubber band go, for this could snap the string or the rubber band. Once you have tied the sting/ribbon/wool etc around the bottom nail, then you can let go of the rubber band chain.
Take your peg/wood/ammo or whatever and place it in the V that the rubber band chain makes. See diagram for best peg positioning.
Take two more pegs or substitutes and use them to angle the catapult.
