Syllabus bites Electricity

Overview

Electricity – what is it?

Girl with hair standing on end

Why is this girl’s hair standing up?

Static electricity was the first kind of electricity that people discovered. We can all produce it by stroking a cat or rubbing a balloon1.

Electricity can do useful work – if you use the correct device you can get heat, light, motion or other forms of energy from electricity. Survey a classroom or a room in your house and find the electrical appliances. You could make a list like the one below.

Static versus current

Extension

Extension: All matter is made of tiny particles.

Graphic showing attraction and repulsion of positive and negative charges

'Like' charges repel, 'unlike' charges attract.

Many of these particles are charged, and the charge may be positive or negative. The particles that are easier to move are called electrons. They have a negative charge and are much too small for us to see. Negative charges repel each other. The hairs on the girl’s head have excess charges and those charges are repelling each other.

If the girl in the picture pushed her hair together, it would spring apart again. We spend energy pushing the hair together. While the hair is held together the energy is stored and we get it back as it springs apart.

The usual way for us to move electrons is through a metal wire. Most metals are good conductors of electricity – they allow the electrons to move through easily.

Extension

Explore further6

Warning – only click here if you’re gamereally hard stuff inside

Links

  1. http://phet.colorado.edu/en/simulation/balloons
  2. http://www.thetech.org/exhibits/online/topics/11b.html
  3. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/vandeg.html
  4. http://www.codecheck.com/cc/BenAndTheKite.html
  5. http://dsc.discovery.com/tv-shows/mythbusters/mythbusters-database/ben-franklin-electricity.htm
  6. http://www.thetech.org/exhibits/online/topics/1xb_flash.html