Static Electricity and Static Electricity and LightningLightning

9.10

Advantages of Advantages of Static ElectricityStatic Electricity

Pollution control in industryRemoval of pollutants and dust

from the airChemical precipitation in industry

Disadvantages of Disadvantages of Static ElectricityStatic Electricity

Hairs and dust cling to clothingSparks creating fires and

explosions

LightningLightningLightning occurs when the negative

charges concentrated near the bottom of the cloud returned to the ground in a huge spark.

Lightning appears jagged because it follows concentrations of positive ions, of the path of least resistance.

Tall objects such as trees and skyscrapers are most likely to become conductors.

LightningLightningLightning rods are used to help

neutralize and to conduct lightning to the ground .

Lightning and Safety: Outdoors: stop playing golf, soccer,

tennis… Get out of pools, lakes…

Indoors: avoid taking showers or baths. Do not handle electric appliances. Turn off TV’s and stereos.

Section 9.10 LightningSection 9.10 Lightning

Did you know lightning is static electricity moving between two clouds or a cloud and the ground?

Lightning is the spark you might see in the sky during a thunderstorm and is five times hotter than the surface of the sun.

Even though lightning may discharge an enormous amount of electricity, because lightning lasts for such a short amount of time, the electricity cannot be trapped to be a source of energy.

Flashes of lightning can be very dangerous. Lightning can start fires, knock over trees and even injure or kill people.

Lightning tends to strike the highest objects such as a tall tree, telephone pole or a person who may be standing in a flat field.

There are many things that a There are many things that a person may do to stay safe if person may do to stay safe if

a thunderstorm is close:a thunderstorm is close: Stay away from water: don't stand

under an umbrella, or keep swimming; Go indoors or into a car if possible Stay away from telephone poles Stay away from trees Stay on low ground, and avoid being the

tallest object If you are in a field, crouch low Stay away from anything metal, such as

a bicycle, or golf club

If you are inside:If you are inside: Stay away from windows and doors

because of metal hinges and doorknobs. Stay away from water taps that might

conduct electricity like tubs or sinks. Don't use and unplug any electric

appliances like the television, a toaster, computer or iron.

Do not use a telephone unless it is an emergency.

Task 1: Design a safety poster telling people at least two ways of how to be safe during a thunderstorm and to avoid lightning.

Insulators and Insulators and ConductorsConductors

• In order to use electricity to our advantage, we need both insulators and conductors.

• An insulator is a substance which slows the free movement of electrons from atom to atom.

• Since insulators do not allow the free movement of electrons, they can encourage the build up of static charge on the surface.

Insulators and Insulators and ConductorsConductors

• A conductor is a substance in which electrons can move freely from one atom to another.

• On the other hand, since conductors such as copper allow the free movement (conduction) of electrons, a static charge can never build up.

Static Electricity and Static Electricity and WinterWinter

The reason static electricity is worse in the winter is that the cold air is drier then the rest of the year and contains few water molecules.

Dry air is an insulator and does not easily pick up the charges from our body.

Therefore, any static charges that build up on our clothes and body tend to stay.

Common Insulators and Common Insulators and ConductorsConductors

Good Fair GoodConductors Conductor Insulator

Copper Carbon FurGold Human body

RubberMercury Earth WoodIron Water Vapour Paper

Dusty Dusty

This charging effect is known as induced charge separation.

Glass Rubber+ -

Gold Wool- +Copper Silk- +

+ -

-+

Calcium Sulfur

Cotton Paraffin wax

Object 1 Charge Object 2 Charge