ElectricityChapter 10

Recall this info…

• All matter is made of atoms which are the smallest particle of an element that has all the properties of that element.

An atom has:– Protons (+)– Neutrons(No Charge)– Electrons (-)

Remember atoms usually have the same number of protons

and electrons….this makes the atom neutral.

More Recall

• The object that gains electrons : NEGATIVE charge

• The object that loses electrons : POSITIVE charge

• Only electrons move causing a change in the charge, not protons.

Electric Forces

• When charged particles come near one another they give rise to two different forces:

1) Force of Attraction -Pulls objects together

-Exists between oppositely charged particles

2) Force of Repulsion

-Pushes objects apart

-Exists between particles of the same charge

+ -

+ +

- -OR

Electric Field

• Electric Field- is the region surrounding a charged particle in which an electric force affecting other charged particles is noticeable

The strength of an electric field

depends upon the distance from the charged particle

Types of Electricity

• Electricity- The energy associated with electrons that have moved from one place to another.

• 2 Kinds of Electricity– Static–Current

Static Electricity• Static Electricity- The buildup of electric charges

on an object• One object gains electrons and the other object

loses electrons.– Then they become oppositely charged– Then they attract each other

• Static Electricity Eventually leaves the object– Into the air or onto another object.– http://www.cabrillo.edu/~jmccullough/Videos/SWF/static.swf

Methods of Charging Static Electricity

1) Friction – 2 Objects rubbing against each other2) Conduction – Charging by direct contact of objects.

-Electrons flow through one object to another

-Examples of conductors: Silver, Copper, Aluminum

-Examples of insulators ( Do NOT allow electrons to flow freely): Rubber, Glass, Wood, Air, Plastic

3) Induction – Rearrangement of electric charges by coming close to a charged object. No contact necessary

Grounding• Grounding- The process of removing the charge on a

charged object by connecting it to the Earth

• Electric Discharge – The loss of static electricity as electric charges move off an object.

• Example: Lightning Rod – (DO NOT WRITE) Are attached to the tops of buildings and a wire connects the rod to the ground. When lightning strikes the rod it travels through the rod and wire and is dispersed into the ground.

Lightning• During a storm, particles contained in

clouds are moved about by the wind. Charges become separated and there are buildups of + and – charges. If a negatively charged cloud forms near the surface of the earth, objects on Earth become charged by induction. Soon electrons are jumping from the cloud to the earth. The result of this transfer of electrons is a giant static spark. Can also occur from cloud to cloud.

• http://www.youtube.com/watch?v=RDDfkKEa2ls