electricity and electromagnetism

Electricity and Electromagnetism

What is Electricity?• Electricity is a form of energy

resulting from charged particles

What are the 2 types of electricity?

Static Electricity• Static electricity is the

buildup of electrical charges on an object

• EX- static buildup on clothes from a clothes dryer.

Current Electricity• Current electricity is the

flow of electrical charges through a path.

• EX- appliances get electricity from a current of electricity.

Static Electricity• Static electricity(1 time discharge)-

buildup of electrical charges. Example: socks clinging together from a dryer.

• **Object with positive electrons and an object with negative electrons that touch creates static electricity.

• Discharge- a movement of static electricity. Example: a shock from touching a metal doorknob after walking across carpet; lightning

Electrical Charges + -• Can be positive or negative• Opposite charges attractEx: positive and negative charges will cling

or pull together) + -• Like charges repelEx: two negatives will pull away from each

other - -• Electrons are NEGATIVE charges.

Conductors

• Allow electricity to flow through easily. • Examples: metal, copper, aluminum, water, steel

Insulators

• Do not allow electricity to flow through easily (protects from electricity flow and discharge.

• Examples: rubber, plastic, wood

Current Electricity• EQ’s ?????????1. How does electricity flow?

2. What kinds of electric circuits are there?

Current Electricity (Flow)• electric current- the FLOW of electricity

through a path of conductors (such as wires).

• Current electricity flows in a circular path called a CIRCUIT.

Circuits (there are 2 kinds)

Series Circuit• Has only one path

through which electricity can flow through.

Example: Christmas tree lights.

Parallel Circuit• Has more than one path

through which electricity can flow.

Example: The wiring and electric circuit in a home.

Open & Closed Circuits

Open Circuits• In a circuit, the path of

conductors is BROKEN or OPEN and results in the flow of electricity stopping.

For example:When a light switch is

turned OFF, the circuit is OPEN.

Closed Circuit• The path of conductors is

CLOSED and results in electricity continuing to flow.

For example:When a light switch is

turned ON, the circuit is CLOSED.

Switch• A Switch is a device that can open or

close the path in a circuit.

• Open Circuit • Closed Circuit

Voltage SourceVoltage or energy source pushes the

electrons through the circuit. For electrons to flow through a circuit, there must be an energy or voltage source.

Examples:Batteries (have a positive and negative

charge)Power plant

Resistor• Resistor- an object in an electrical circuit

that RESISTS the flow of electrons. • Electrons lose energy when they move

through a resistor. This lost energy is turned into heat or light.

Example: light bulb

Using Electricity SafelyEQ: How can you use electricity safely?

When too many appliances are plugged into the same power source (plug), the current of electricity can increase. This current can become large enough to start fires.

If you touch two power lines at the same time, or one power line and the ground it can be dangerous.

Fuses and Circuit Breakers• Fuse- a wire (conductor) that breaks if too

much current flows through it. • Circuit breaker- a switch that OPENS the

circuit (turns off) when it detects there is too much current. This is a safety feature for most electrical circuits in homes.

• Ground fault interrupter (GFI)- usually in bathrooms or kitchens. This will turn off a circuit if a short circuit forms or electricity starts to flow through water.

MagnetismWhat is magnetism?

Magnetism is the ability of an object to push or pull on another object that has magnetic property.

magnetsMagnets have many uses in our everyday

lives. What are some examples?

All magnets have north and south poles.• Like poles REPEL• Opposite poles ATTRACT

Questions to think about..What else have we learned about that

attracts or repels?

What else do we know about that has a north and south pole?

Is the earth magnetic?

Do magnets come in different shapes and sizes?

Yes! Including- bars, horseshoes, rings and flat sheets.

What would happen if you cut a magnet in half?

If you cut a magnet in half, each half will form two new magnets with two poles (a north and a south) on each.

• Magnetic field- strength and direction of a magnet’s force.

(when you sprinkle iron filings around a magnet, you can see this field.)

The closer the lines are, the stronger the magnet forces.

ElectromagnetismEQ’s• What are electromagnets?

• How do electromagnets create a magnetic field?

electromagnet• Electromagnet- an electric circuit that

produces a magnetic field.

• Electromagnets have at least 2 parts:1. a source of electricity (battery) 2. a conductor (wire)

Where are electromagnets used?

• Electromagnets are used in many ways and are in many appliances we use everyday. They are in:

Doorbells, computers, clocks, speakers, small appliances….

• How can you make an electromagnet stronger and thus increase the magnetic field?

make an electromagnet STRONGER by:

• increasing the number of coils in a wire• put an iron rod in the inside of the coil.• increase the voltage. (for ex: add more

batteries or a bigger battery)

What are the differences between electromagnets and PERMANANT magnets?

Permanant magnets• Have a north and

south pole• Can’t be turned on

or off

Electromagnets (temporary)• Have a north and south

pole• Can be turned on or off• Strength can be

changed

Generators• How can electromagnets produce

electricity?

• Generator- a device that creates electric current by spinning an electric coil between the poles of a magnet.

Alternating Current• Alternating Current- electric current that

rapidly changes directions.

Alternating currents are created in real generators that change direction 120 times each second.

Magnetic levitationMagnetic levitation- the lifting of an object by

the means of magnetic forces.

Magnetic levitation happens when two like poles of magnets face each other creating a pushing force against the force of gravity.