Basics of Electricity. What is Electricity? Involves the movement of electrons Is invisible Provides light, heat, sound, motion... Has been practical.

Basics of Electricity

What is Electricity?

• Involves the movement of electrons• Is invisible• Provides light, heat, sound, motion . . .• Has been practical for use over the last 100 years

History2500 years ago, the Greeks rubbed amber with other materials.

They discovered that this process would attract feathers and other lightweight materials to the amber.

History

Ben Franklin suggested that . . .

. . .opposite charges attract

and like charges repel.

+ -

History

Ben Franklin suggested that . . .

. . .opposite charges attract

and like charges repel.

+ +

The Law of Charges explains why the electrons continue to be bonded to the nucleus.

Electron Flow

An electron from one atom can knock out an electron from another atom.

Electron Flow

Electricity is created as electrons collide and transfer from atom to atom.

Play Animation

What Makes Up Electricity?

Let’s compare it to something we know --- Water!

Water Analogy

Tank = Battery

Pipe = Wiring

Faucet = Switch

Tank Faucet

Pipe

Current

Current: The flow of electric charge

When the faucet (switch) is off, is there any flow (current)?

NO

When the faucet (switch) is on, is there any flow (current)?

YES

Tank (Battery) Faucet (Switch)

Pipe (Wiring)

Current in a Circuit

When the switch is off, there is no current.

When the switch is on, there is current.

off onoff on

Voltage

Voltage: The force (pressure) behind the flow of current

When the faucet (switch) is off, is there any pressure (voltage)?

YES – Pressure (voltage) is pushing against the pipe, tank, and the faucet.

When the faucet (switch) is on, is there any pressure (voltage)?

YES – Pressure (voltage) pushes flow (current) through the system.

Tank (Battery) Faucet (Switch)

Pipe (Wiring)

Voltage in a Circuit

The battery provides voltage that will push current through the bulb when the switch is on.

off onoff on

Resistance

Resistance: The opposition to the flow of current.

What happens to the flow (current) if a rock gets lodged in the pipe?

Flow (current) decreases.

Tank (Battery) Faucet (Switch)

Pipe (Wiring)

Resistance in a Circuit

Resistors are components that limit the flow of electricity.

Reducing current causes the bulb to become more dim.

off on

Resistor

Types of Electricity

(You might already know these!)

Types of Electricity

Static ElectricityThe electrical charge an object develops as a result of having an unequal number of protons and electrons.

Current ElectricityThe movement of electrons through a conductor.

Static Electricity

• Uncontrollable Electricity

• Lightening• Static Cling• Wool socks on a carpet

“shocks”

Current Electricity

Two Types:

Alternating Current (AC)

Direct Current (DC)

Direct Current

The electrons flow in the same direction all the time, from negative to positive.

- +

Direct Current

Comes from• Batteries• Converted from Alternating Current

Used for electronic devices including• Computers• iPods• Cell phones• Anything that has a “charger”

Alternating Current

The electrical current (movement of electrons) changes direction.

Alternating Current

Comes from Generators• Coal burning and nuclear power plants• Hydroelectric power plants• Wind and solar generators

Used for• Motors• Heaters• Lights• Anything that plugs into the wall

Image Resources

Microsoft, Inc. (2008). Clip Art. Retrieved September 10, 2008, from http://office.microsoft.com/en-us/clipart/default.aspx