static electricity lesson

8/2/2019 Static Electricity Lesson

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ELECTRICKERY

Presented byPresented by



Have you ever stuck a balloon to theHave you ever stuck a balloon to the

wall af ter rubbing it on your head?wall af ter rubbing it on your head?

Has your jumper ever made cr acklingHas your jumper ever made cr acklingnoises when you took it off ?noises when you took it off ?

Have you ever got an electric shockHave you ever got an electric shock

off your door knob?off your door knob?

Have you ever seen lightening?Have you ever seen lightening?



All these things happen

because of

Static

Electricity



What is Static Electricity?

Static electricity occurs when there isStatic electricity occurs when there is

a build up of electric charge on thea build up of electric charge on the

sur fa

ce of a

materi

al.sur

face o

f a

materi

al.

It is called static electricity becauseIt is called static electricity because

the charges don¶t move.the charges don¶t move.

The electricity we use everydayThe electricity we use everyday

involves moving charges.involves moving charges.



What is charge?

To understand charge we have to lookTo understand charge we have to look

at things on an extremely small scale.at things on an extremely small scale.

We have to try and understand thingsWe have to try and understand thingsthat we can¶t even see with the mostthat we can¶t even see with the most

power f ul microscope.power f ul microscope.

Atoms!



The atom

Everything we see around us everyday isEverything we see around us everyday is

made of atoms.made of atoms.

We can¶t see individual atoms becauseWe can¶t see individual atoms because

they are so small.they are so small.

In fact the diameter of an atom is aboutIn fact the diameter of an atom is about

0.0000000001m0.0000000001m

In the air in your classroom there are aboutIn the air in your classroom there are about1500000000000000000000000000 atoms.1500000000000000000000000000 atoms.



What is inside the atom?

The atom is made of 3 sorts of particles.The atom is made of 3 sorts of particles.

The electronThe electron

The protonThe proton

The neutronThe neutron

We can imagine each as a tiny little ball. We can imagine each as a tiny little ball.



Inside an atom

The protons andThe protons and

neutrons sitneutrons sit

together in a lumptogether in a lump

in the middle calledin the middle calledthe nucleus.the nucleus.

The electrons orbitThe electrons orbit

around thearound the

nucleus, a bit likenucleus, a bit like

the planets orbitingthe planets orbitingthe Sun.the Sun.

Most of the atom is empty space if Most of the atom is empty space if

atoms were the size of f ootball f ields,atoms were the size of f ootball f ields,

the nucleus would be a gr ain of sand inthe nucleus would be a gr ain of sand in

the middle and the electrons would bethe middle and the electrons would be

orbiting around the edge. orbiting around the edge.

..



Charge

The electron is negatively charged.The electron is negatively charged.

The proton is positively charged.The proton is positively charged.

The neutron has no charge, it is neutr al. The neutron has no charge, it is neutr al.



Charge

Most things have the same number of Most things have the same number of

electrons and protons in them.electrons and protons in them.

They don¶t have any over all charge.They don¶t have any over all charge. If this isn¶t true interesting things canIf this isn¶t true interesting things can

happen.happen.



Atoms«

HaveHave neutronsneutrons,, protonsprotons, and, and

electronselectrons..

Protons areProtons are positivelypositively chargedcharged

Electrons areElectrons are negativelynegatively

chargedcharged



Electrons«

Are located on the Are located on the outer outer edges of atoms«they can beedges of atoms«they can be

movedmoved.. A A concentr ationconcentr ation of electrons inof electrons inan atom creates a netan atom creates a net

negativenegative charge.charge. If electrons areIf electrons are strippedstripped away,away,

the atom becomesthe atom becomes positivelypositively

charged.charged.



+

-

+

+

++

The wor ld is f illed with electrical

charges:

+

+

+

+

+

-

-

- -

-

-

- --



What is this electrical potential

call

ed?Static ElectricityStatic Electricity

- --

--

-

- ++++

+



Static Electricity

TheThe build upbuild up of an electricof an electriccharge on thecharge on the sur facesur face of anof an

object.object.The charge builds up butThe charge builds up but doesdoes

not flow.not flow.

Static electricity isStatic electricity is potential potential energyenergy. It does. It does notnot move. It ismove. It isstoredstored..



Static Discharge«

Occurs when there is a Occurs when there is a lossloss of of

static electricity due to threestatic electricity due to three

possible things:possible things:FrictionFriction -- rubbingrubbing

ConductionConduction ± ± direct contactdirect contact

InductionInduction ± ± through anthrough an

electrical f ield (not directelectrical f ield (not direct

contact)cont

act)



How do charges behave?

What do you know about magnets?What do you know about magnets?

2 north poles will repel each other, but2 north poles will repel each other, buta north and a south put together will a north and a south put together will

attr act one another .attr act one another .

opposites attr act, likes repel.opposites attr act, likes repel.



How do charges behave?

Exactly the same thing happens withExactly the same thing happens with

charges.charges.

2 positive ch

arges put together wi

ll 2 positi

ve ch

arges put together wi

ll repel each other .repel each other .

Put a positive charge near a negativePut a positive charge near a negative

charge and they will attr act eachcharge and they will attr act each

other .other .

A charged object may even attr act a A charged object may even attr act a

neutr al one.neutr al one.



Static electricity

Static electricity is caused whenStatic electricity is caused whencertain materials are rubbed againstcertain materials are rubbed againsteach other .each other .

Electrons can be rubbed off oneElectrons can be rubbed off onematerial and on to another . material and on to another .

The material that has got extr a The material that has got extr a

electrons is now negatively chargedelectrons is now negatively charged The material which has lost electronsThe material which has lost electrons

is positively charged.is positively charged.



+

+

+

+

+

+

+

+

+

+- -

-

-

-

-

- -

-

-



Static electricity

It is this imbalance of positive andIt is this imbalance of positive and

negative charges that causes:negative charges that causes:

Ball

oons to stick to wall

s.

Ball

oons to stick to wall

s.

Your hair to stand on end when brushYour hair to stand on end when brush

your hair on a dry day.your hair on a dry day.

And the e

lectric shock you sometimes

And the e

lectric shock you sometimesget f rom the door handle.get f rom the door handle.



Your Turn to Experiment



Lightning



Lightning

kills morekills more

than 60than 60

people andpeople and

injures moreinjures more

than 400than 400

people a year people a year in the USin the US

one mile everyone mile every

five secondsfive seconds

about 20,000 Cabout 20,000 C

Voltage of up toVoltage of up to

1.2x101.2x1088 voltsvolts



What causes lightning?

Lightning is actuallyLightning is actually just static electricity just static electricityon a much larger on a much larger

scal

e.

scal

e.

The rubbing isThe rubbing iscaused by air caused by air moving aroundmoving around

In thundercloudsIn thundercloudsbottom is usuallybottom is usually

negative and top isnegative and top ispositive.positive.



Thunder

When the lightning flash happens itWhen the lightning flash happens it

heats the air to a temper ature 5 timesheats the air to a temper ature 5 times

hotter than the sur face of the sun.hotter than the sur face of the sun.

This causes nearby air to expand andThis causes nearby air to expand and

vibr ate f orming the sound we hear asvibr ate f orming the sound we hear as

thunder .thunder .



Interesting facts

Lightning bolts can tr avel at speeds of Lightning bolts can tr avel at speeds of

up to 60,000 miles per second.up to 60,000 miles per second.

Every second

around 100 bo

lts o

f E

very second

around 100 bo

lts o

f lightning strike the Earth.lightning strike the Earth.

One lightning bolt has enoughOne lightning bolt has enough

electricity to power 200,000 homes. electricity to power 200,000 homes.

You are more likely to be struck byYou are more likely to be struck by

lightning than be eaten by a shark.lightning than be eaten by a shark.



Some myths

Lightning never strikes in the same placeLightning never strikes in the same place

twice. twice.

False, the Empire State Building isFalse, the Empire State Building is

reportedly struck 100 times a year .reportedly struck 100 times a year . Wearing rubber shoes will protect me in a Wearing rubber shoes will protect me in a

thunder storm.thunder storm.

Fal

se, Lighting is too power f ulto beF

alse, Lighting is too power

f ulto bestopped by half an inch of rubber or sever al stopped by half an inch of rubber or sever al

hundred f eet of rubber f or that matter .hundred f eet of rubber f or that matter .



Limit Exposure

static electricity lesson

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