ch.12.less.5.how do we use electricity and magnetism (part 1)

HOW DO WE USE ELECTRICITY AND MAGNETISM? (PART 1)Chapter 12: Lesson 5:

WHAT IS MATTER?Matter is everything around us that has

mass and volume

Recap

WHAT IS MATTER MADE OF?

Matter is made of very small building blocks called ‘ATOMS’

WHAT ARE ATOMS?

•Smallest part of any matter•Cannot be seen with a normal microscope (use electron microscope)

•Example:Oxygen CarbonN.B. Water (H₂O)is made of 1 atom of oxygen and 2 atoms of hydrogen)

WHAT DO ATOMS LOOK LIKE?

ATOMS…

•Have neutrons, protons, and electrons.•Protons are positively (+) charged •Electrons are negatively (-) charged

Positive and Negative Charge

Opposites charges attract

Same charges repel

STATIC ELECTRICITY

•The build up of an electric charge on the surface of an object.

•The charge builds up but does not flow.•Static electricity does not move. It is stored.

EXAMPLES OF STATIC

ELECTRICITY

Try rubbing a balloon against a wool cloth

Place the balloon over anybody’s hair

and watch what happens

1) BALLOON EXPERIMENT

When we rub the balloon against a

wool cloth, the balloon gains a

negative charge (-)

The (-) charge in the balloon attracts the

(+) charge in the hair causing the hair to

stand.

EXPLANATION

Try rubbing a comb against a wool cloth

The comb will gain a negative charge

Bring the comb near some pieces of paper

2) COMB EXPERIMENT

Initially the paper is uncharged, but the comb attracts the positive

charges in the paper and repels the negative charges.

Rubbing of rain drops and ice inside a

storm cloud

When the (-) charges get large enough they jump to the ground as

lightning.9

3) LIGHTNING(IS CAUSED BY)

CURRENT ELECTRICITY

(CURRENT ELECTRICITY)•A flow of electrical charges through a circuit.

(Circuit is a path along which electric current flows)

Circuits should have 3 parts

Power sourceBattery (cell)

LoadBulb / Motor

ConnectorsWires

Power source

Load

Connectors

Types of circuits

Open circuitsBroken circuits (Incomplete)

Closed circuitsUnbroken circuits

(Complete)

CIRCUITS’ SYMBOLS:

1) Battery

2) Bulb

3) Wires

(A straight line)

4) Switch (off)

5) Switch (on)

6) Motor

7) Buzzer

SERIES AND PARALLEL CIRCUITS

SERIES CIRCUIT

• Series circuit - has only one path through which the electricity can flow.

• In the above diagram, the electricity flows through both loads.

PARALLEL CIRCUITS

• A parallel circuit has multiple paths through which the electricity can flow.

• In a parallel circuit, the current though one path may be different than the current through the other path.

PARALLEL CIRCUIT

• Place two bulbs in parallel. What do you notice about the brightness of the bulbs?

• Add a third light bulb in the circuit. What do you notice about the brightness of the bulbs?

• Remove the middle bulb from the circuit. What happened?

SIMPLE CIRCUITS

• Series circuit• All in a row• 1 path for electricity• 1 light goes out and

the circuit is broken

• Parallel circuit• Many paths for

electricity• 1 light goes out and

the others stay on

Conductors and Insulators

A conductor is a substance through which electric charge flows readily. An insulator is a substance that strongly resists the flow of electric charge.