Transcript Unit 2: Electricity

Mr. Fleming
9.2: The electrical force is a universal force that
exists between any two charged objects.
D4. Explain the relationship among voltage,
current and resistance in a simple series
circuit.
D5. Explain how electricity is used to produce
heat and light in incandescent bulbs and
heating elements.
D6. Describe the relationship between current
and magnetism.

What is electricity and how does it move
within an object?

Electricity: energy
due to the
movement of
electrons through a
material.
◦ Protons stay put

Discovered by Ben
Franklin.

All objects are made of atoms
◦ Contain electrons, protons, and neutrons.

Not Charged
◦ Objects charge= # of protons - # of electrons
◦ Objects that have an equal amount of electrons and
protons

Charged
◦ Objects can be negatively charged or positively
charged.
◦ Positively Charged=more protons than electrons
◦ Negatively Charged=more electrons than protons


Static electricity:
electricity involving a
build-up of stationary
charges.
Current electricity:
electricity involving the
flow of e- through a
material.


The accumulation of excess electrical charge
on an object.
To create static electricity:
◦ Electrons are transferred between materials
◦ By friction/rubbing causing one material to build
up an excess of electrons
◦ Second material ends up with a shortage of
electrons.
- charge = material with
excess of electrons
+ charge= material with
shortage of electrons

If the difference in
charges becomes large
enough the electrons
jump from – to +
creating a spark
(lightning)
What does electricity represent:
a.
b.
c.
d.
The movement of protons.
The movement of neutrons.
The movement of electrons.
All of the Above
Movement of Electrons
What causes a spark or lightening to happen?
a. Two objects that have an equal distribution of
positive and negative charges.
b. Two objects that are only positively charged.
c. When two objects build-up a difference in charge
between each other.
d. Two objects that are negatively charged.
c. When two object build-up a difference in charge
between each other.

Balloons

Like charges repel, unlike charges attract.
“Likes repel. Opposites attract.”


Electrical events simply rearrange the charges
or move them from one object to another
object
Total charge= positive + negative charges
within universe is 0.


Charged objects are
surrounded by an
electrical field that is
similar to magnetic
fields.
Electrical Field – a force
exerted by a charged
object.

Conductor
◦ A material in
which electrons
are able to move
easily.

Insulator
◦ A material in
which electrons
are not able to
move freely.


Static charges are not noticed until something
interacts with their field or they move by:
Charging by Contact or Conduction
◦ Rub two material together results in transfer of
electrons.
◦ One object has positive charge
◦ One object has negative charge
◦ OBJECTS TOUCH

Charging by Induction
◦ The rearrangement of electrons on a neutral object.
◦ Caused by presence of other object’s electric field.
◦ Objects DO NOT TOUCH.
Choose TRUE or FALSE
1. T or F. Opposite charges DO NOT attract
each other.


False
2. T or F. All charged objects have electrical
fields?

True
3. An insulator is:
A. Good at keeping heat in or out.
B. Make it easy for electrons to pass through.
C. Make it hard for electrons to pass through.
D. Both A & C
D. Both A & C
What is the difference between conduction and
induction?
A. One involves the movement of protons instead of
elections
B. One does not change the arrangement of electrons.
C. Conduction is the rearrangement of electrons by
touch while induction is rearrangement without touch.
C. Conduction is the rearrangement of electrons by
touch while induction is rearrangement without touch.