3. •Electricity is a form of
energy. Electricity is the
flow of electrons . All
matter is made of atom
which contain positively
charged proton ,
negatively charged
electron & uncharged
ELECTRICITY
4. STATIC ELECTRICITY
•When electricity or charge is confined in an
object that means the current is not moving
from one place to another is called Static
Electricity.
5. CHARGE
•Charge is the
fundamental property
of forms of matter that
exhibit electrostatic
attraction or repulsion
in the presence of
other matter.
6. WHERE DO CHARGE COME FROM ?
• If electrons = protons neutral
• If electrons > protons gaining electrons, negative charge
• If electrons < protons losing electrons, positive charge
7. WHERE DO CHARGES COME
FROM?
When a balloon rubs a piece of wool...
– electrons are pulled from the
wool to the balloon.
The balloon has more electrons than
usual.
+
+
+
+
+
–
–
–
–
–
The balloon: – charged,
The wool: +chargedwool
8. WHERE DO CHARGES COME
FROM?
Rubbing materials does NOT create electric
charges. It just transfers electrons from
one material to the other.
9. TWO KINDS OF CHARGES
• After being rubbed, a
plastic ruler can attract
paper scraps.
Ruler carries electric charge.
It exerts electric force on paper.
The interaction between static electric charges is called
electrostatics.
This charging method is called charging by friction.
10. HOW CAN YOU CHARGE OBJECTS?
• There are 3 ways objects can be charged:
1. Friction
2. Conduction
3. Induction
**In each of these, only the electrons move. The protons stay
in the nucleus**
11. FRICTION
• Charging by friction occurs when electrons are “wiped” from
one object onto another.
Ex.
If you use a cloth to rub a plastic ruler, electrons move from the
cloth to the ruler.
The ruler gains electrons and the cloth loses electrons.
12. CONDUCTION
• Charging by conduction happens when electrons
move from one object to another through direct
contact (touching).
Ex. Suppose you touch an uncharged piece of metal
with a positively charged glass rod. Electrons from
the metal will move to the glass rod. The metal
loses electrons and becomes positively charged.
13. INDUCTION
• Charging by induction happens when charges in
an uncharged object are rearranged without direct
contact with a charged object.
Ex.
If you charge up a balloon through friction and
place the balloon near pieces of paper, the charges of
the paper will be rearranged and the paper will be
attracted to the balloon.
14. CONSERVATION OF CHARGE
• When you charge something by any method, no
charges are created or destroyed.
• The numbers of electrons and protons stay the same.
Electrons simply move from one atom to another,
which makes areas that have different charges.
15. INSULATORS AND CONDUCTORS
Insulators: materials that do NOT allow
electrons to flow through them easily.
Insulators can be easily charged by friction as the extra
electrons gained CANNOT easily escape.
16. INSULATORS AND
CONDUCTORS
Conductors: materials that allow electrons to flow
through them easily.
Conductors CANNOT be easily charged by friction as
the extra electrons gained can easily escape.
17. GROUNDING
How does grounding occur?
+
+
++
+
When we touch a metal ball of
positive charge...
electrons flow from the
earth to the metal ball to
neutralize the metal ball.
Metal ball becomes neutral.
18. Similarly, if the metal ball is of
negative charge...
GROUNDING
How does grounding occur?
–
–
––
–
extra electrons flow
from the metal ball to
the earth and the ball
becomes neutral.
19. ELECTRIC DISCHARGE
• The loss of static electricity as charges move
off an object is called electric discharge.
Sometimes,
electric
discharge
happens
slowly.
Ex: static on
clothes
Sometimes,
electric
discharge
happens
quickly.
Ex. wearing
rubber-soled
shoes on
carpet,
20. LIGHTING
• Lighting usually strikes at the highest point in a charged area.
• Lighting caused because of the static discharge of any charged
point.