Electrostatics

Observe the beauty and power of lightning

Lightning strikes over the Pacaya Volcano

How is it possible to produce such electric spark? It is basically a large electrical discharge

Almost all of us are familiar with static electricity because we can see and feel it in the winter. On dry winter days, static electricity can build up in our bodies and cause a spark to jump from our bodies to pieces of metal or other people's bodies. We can see, feel and hear the sound of the spark when it jumps.

Why are paper attracted to the comb?

You may also have the experience of hearing a crackling sound as your take off a nylon sweater. Can you explain?

The crackling is caused by small electric sparks.

Charged by Rubbing

The electron theory The atoms of all substances contain both negative and positive charges.

Why rubbing things together product electricity? When you rub two different materials together, electrons can rubbed off one materials and on to the other. These electrons are very tiny. Each electrons carries a small electrical charge If you rub two pieces of the same materials together, electrons don’t move. (because of equal chance)

When two substances are rubbed, some of the outer electrons moved to one of substances

One substance will has extra number of electrons (so it is negatively charged). Another substance has fewer electrons (so it is positively charged)

Why rubbing things together produces electricity ? When two different materials are rubbed together, ________________ are rubbed off one material and on to the other. The material that gains electrons becomes _____________ electrical charged. The material that loss electrons becomes _____________ charged These two charges are exactly ____________ in size.

Like charge repel

Like charges repel

Unlike charges attract

Van de Graaff Generator - a device to produce charge easily

THE PLASTIC ROLLER BECOMES ELECTRIFIED

Making use of static electricity

The sky is filled with electric charge. In a calm sky, the + and - charges are evenly interspersed thoughout the atmosphere. Therefore, a calm sky has a neutral charge.

When the clouds move, they are rubbed.