Static Electricity

Positive and Negative Charge

Same charges repel

Positive and Negative Charge

Unlike charges attract

Ben Franklin discovered lightening was static

electricity

What is Charge?

Atoms are composed of protons (+), electrons (-) and neutrons. The nucleus contains the protons

and neutrons and the electrons surround the nucleus.

What is Charge?

Protons are much larger than electrons but have an equal and opposite charge.

Force on an Uncharged Particle

Initially the paper is uncharged, but the comb polarizes the charges in the paper.

Conductors and Insulators

A conductor is a substance through which electric charge flows readily. An insulator is a substance that strongly resists the flow of electric charge.

Conductor

insulator

Enlargement of 5 mm square

computer chip.

Static electricity

is produced

by friction

between ice and water in the huge

cloud

Lightening

http://upload.wikimedia.org/wikipedia/commons/c/c2/Van_de_graaf_generator.svg

Effect of Van De Graaf

• Hair is pushed apart as all the electrons on the hair repel each other.

Summary

H/W

• P 370/1• Q 1,2,3,13.