A wind-up toy
A wind-up (mechanical) toy moves by the force of a spring or a rubber band. By turning the key we wind the spring and store energy in it, and the toy spends this energy slowly as it moves. Long ago craftsmen made moving devices with small levers and gears. In ancient Greece there were said to be mechanical puppets that made sounds. Later came clockwork toys: music boxes, singing birds, dancing figures, wind-up trains and steamships.
You need: 8×15 cm card, 2 drinking straws (9 cm), 2 wooden skewers (11 cm, blunt ends), 4 bottle caps, glue and tape, 1 rubber band, 1 paper clip, play-dough. Steps: 1) Tape the straws across the underside of the card, 2 cm from each end; do not stick the skewers to them. 2) An adult makes a hole in the middle of each cap with a needle or nail and widens it to fit a skewer. 3) Pass the skewers through the straws, press a cap on each end and fix it with a little glue or play-dough so the wheels turn with the skewer. 4) Tape the paper clip to the front edge of the card. Hook one end of the rubber band onto the clip and tape the other end to the middle of the rear skewer. 5) Roll the car backwards on the table so the band winds round the skewer, then let go. Safety: an adult must file or cover the skewer ends with play-dough; only an adult makes the holes; never shoot rubber bands at anyone.