Electri

Static ElectricityThe build up of an electric charge

on the surface of an object.

The charge builds up but does not flow.

Static electricity is potential energy. It does not move. It is stored.

Electricity that moves…

Current: The flow of electrons from one place to another.

Measured in amperes (amps)

Kinetic energy

There are 2 types of currents:

Direct Current (DC) – Where electrons flow in the samedirection in a wire.

There are 2 types of currents:

Alternating Current (AC) –electrons flow in differentdirections in a wire

There are 2 types of circuits:

Series Circuit: the components are lined up along one path. If the circuit is broken, all components turn off.

Series Circuit

There are 2 types of circuits:

Parallel Circuit – there are severalbranching paths to the components. If the circuit is broken at any one branch, only the components on that branch will turn off.

Parallel Circuit

Conductors vs. InsulatorsConductors – material through

which electric current flows easily.

Insulators – materials through which electric current cannot move.

ExamplesConductors:

Metal

Water

Insulators:

Styrofoam

Rubber

Plastic

Paper

What is Resistance?The opposition to the flow of an

electric current, producing heat.

The greater the resistance, the lesscurrent gets through.

Good conductors have lowresistance.

Measured in ohms.

What Influences Resistance?Material of wire – aluminum and

copper have low resistance

Thickness – the thicker the wire the lower the resistance

Length – shorter wire has lower resistance

Temperature – lower temperature has lower resistance

What is Voltage?

The measure of energy given to the charge flowing in a circuit.

The greater the voltage, the greater the force or “pressure”that drives the charge through the circuit.

Difference b/t Volts and Amps

Example – you could say that…

Amps measure how much water comes out of a hose.

Volts measure how hard the water comes out of a hose.

Ohm’s Law

Resistance = Voltage / Current

Ohms = Volts / Amps

Practice with Ohm’s Law

Ohms Volts Amps

4 100 25

15 150 10

2 30 15

9 45 5

6 48 8

What is an electromagnet?

Electromagnet – a magnet made from a current bearing coil of wire wrapped around an iron or steel core.

What is a generator?

Generator – a machine that changes mechanical energy to electrical energy

Usually use moving magnets to create currents in coils of wire.

What is a motor?

Motor – a device that changes electrical energy to mechanical energy that can do work.