ELECTRICITY
TOPIC #1.1 - STATIC ELECTRICITY
STATIC ELECTRICITY
Static electricity is the build-up of electric charge on an object. An object has static
electricity when it has an excess of electric charge.
Electric discharge is the the removal of an electric charge from an object. Lightning is
an example of a large electric discharge.
ELECTRIC CHARGES
There are two types of electric charges - negative and positive.
Electron - a subatomic particle carrying a negative electric charge that is outside the
nucleus of the atom.
Proton - a subatomic particle with a positive electric charge, found in the nucleus of the
atom.
Neutron - a subatomic particle with no electric charge, found in the nucleus of the atom.
When two different types of matter are brought into close contact with each other, one
may lose electrons to the other as shown below.
A negatively charged object gains electrons.
A positively charged object loses electrons thus making the total charge positive.
A neutral charge means that the object has no charge at all.
The “LAWS” of Electric Charges
1.Opposite charges attract each other.
-- ---> <--- +
2. Similar charges repel each other.
-- <--- ---> --!
+ <--- ---> +
3. Charged objects cause CHARGE SEPERATION with neutral objects.
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-- ---> <--- o!
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+ ---> <--- o
Van De Graaff Generator
They produce static build-up by using friction.
A rubber belt rubs on metal and transfers the charge to a sphere, the charge builds up
on the sphere and transfers to you when you touch it.
STATIC ELECTRICITY
1. How does it work?
When you rub your head with a balloon, the balloon will stick to the wall - why? The
reason is that friction made when the two different objects are rubbed together creates
static electricity. Three ways to tell if static electricity is present are:
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1) It sparks and can shock you.
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2) It makes a crackling sound.
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3) It causes things to stick together.
Step 1!!
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Rubbing causes the balloon to!
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“steal” electrons from your hair.!
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Step 2
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The balloon has a buildup of electrons
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so it has a negative charge. Your hair
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has lost electrons so it becomes
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positively charged.
Step 3!!
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Because opposites attract, the!
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negatively charged balloon will!
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stick to the wall.!
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Step 4
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If there are enough electrons on the
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balloon, they will try and “jump” to the
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wall and will make a small spark.
2. Where does static electricity occur?
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Everyday examples include:
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1) Dragging rubber soled shoes can “steal” electrons from the carpet and you
can usually shock someone with your buildup of electrons.
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2) Certain types of cloth rubbing together in the dryer will “steal” electrons
causing clothes to stick together (static cling).
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3) Electrons collect on your TV screen and produce static electricity.
Static Electricity
Name:__________________________ Date:_________________
Use pages 275-278 in Science in Action to answer the following questions:
1. How does a proton differ from an electron?
2. What does it mean to be statically charged?
3. How does a Van de Graaff generator work?
4. a)What happens when like charges interact?
b) What happens when unlike charges interact?
5. You rub your feet across a floor and electrons transfer from you to the
floor. Are you now negative or positively charged?
6. A neutral object contains no charge. Is this statement true? Explain.
7. Why is a neutral object attracted to a charged object?
8. Large trucks that carry flammable liquids often have a metal wire or chain
that drags on the ground. Why?