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Build your own static electricity rotor

 

 

 

 

YOU NEED:

You need

  • An empty cool drink tin
  • Tin snips
  • About 1 metre of thin plank
  • A length of plastic tubing. Rigid water pipe or the centre of fax machine film rollers
  • Bubble wrap or a piece of wool or nylon fabric
  • Wood glue


WHAT TO DO

Cut the bottom

Cut the bottom of the cool drink tin with your tin snips to give you a round dome


Find the centre

Find the exact centre of your plank and spread some wood glue on it

Glue it

Fix your cool drink tin bottom inside out so that the dome points outwards. The wooden plank should balance freely on the domed lid and if you touch it, it should rotate.
Wait for the glue to dry.

The Experiment

Rub the plastic tube vigorously on the bubble wrap, nylon or wool

Hold it about five centimetres away from and parallel to one end of the plank.

What’s happening

The plank will start to rotate in the direction of your plastic tube.
Keep the gap to about five centimetres and you will set the plank rotating on its cool drink tin bearing.

The Science

When you rub the plastic tube on bubble wrap or wool electrons are rubbed of from the wrap and stick to the plastic tube. The tube is now negatively charged. When you bring it close to the plank the negatively charged electrons induce a positive charge on the plank. Opposite charges attract and the plank starts to turn towards the plastic tube. Experiment with various cloths and wraps and see what gives the best results. The dryer the air the better it works.