static electricity

Describe how friction causes static electricity

In insulating materials when materials are rubbed together negatively charged electrons will transfer from one to the other due to friction. This leaves a positive static charge on material that lost elections and a negative static charge on the one that gained electrons.

What is the way that electrons are transferred depend on

The two materials involved

Give example of materials were static electricity is built up due to friction

Polythene rod and cloth- where negative electrons move from cloth to rod

Acetate rod and cloth- where negative electrons move from rod to cloth

What is important note about the transfer of electrons between materials

ONLY ELECTRONS MOVE

• the positive static charge on other material occurs bc an object has lost negative charge not that it’s gained positive protons

Why does no charge build for conductive metals

Because in conducting materials electrons are able to move so they flow straight back again so no charge is built up

Explain how too much static causes sparks

As more and more electrons are being transferred and the force of the charge increase. A potential difference will develop between the charged material and the earthed object. (0v on earth)

If potential difference between charged object and earthed bite is large enough then electrons can jump across the gap and the jumping electrons is what causes spark