Electricity

Circuits and How They Work

What is Electricity?

How Electricity Works

Flashlights Flashlights are a perfect example of how electricity

travels in a path. The electricity flows through the batteries and up to the light bulb and then down through the metal bar on the side. The switch completes the circuit to turn the light on and breaks it to turn it off.

A Simple Circuit Electricity needs to travel in a path

called a circuit.

http://www.rkm.com.au/ANIMATIONS/animation-electrical-circuit.html

Go to the website below to see an animation.

Label the Parts

Label the parts of the circuit below.

load

conductor

switch

powersource

Open and Closed Circuits Since electricity must move in a path, if the path is

broken, the electricity can’t move. Think of when the bridge in Stone Harbor is up. No one can move until it closes again. But when the bridge is down, the path is complete and traffic can start moving again.

Drawbridge is open so traffic is stopped.

Drawbridge is closed so traffic can move.

Open and Closed Circuits

Open Circuits

In an open circuit, there is a break in the path, so the electricity cannot flow.

open circuit –motor won’t move

switch is open

Click here for a great website to practice circuits

Closed Circuits

In a closed circuit, the path is complete, so the electricity can flow.

closed circuit –light bulb lights

switch is closed

Open or Closed Circuit?

Look at the pictures below and decide if they represent open or closed circuits.

open

openclosed

closed

Conductors and Insulators

Conductors are substances that electricity flows through. Metals are good conductors, as well as water. Insulators are substances that electricity does not flow through. They are often wrapped around conductors to keep people safe.

Conductor or Insulator?

Look at the substances below and decide if they are conductors or insulators.

copper

plastic

water

rubber

wood

glass

aluminumsilver

insulator

insulator

conductor

conductor

conductor

insulator

insulator

conductor

Series and Parallel Circuits

Often, more than one item are connected to a power source. This can be done in two ways: series and parallel circuits.

In a series circuit, one switch controls all of the items in the circuit.

In a parallel circuit, more than one switch is needed so that the items can be turned on an off individually.

The big difference between a series and parallel circuit is the number of switches. A series has one, where a parallel has more than one.

Series Circuits

In a series circuit, all of the items are connected to one circuit and controlled by one switch. All the items are turned on and off at the same time.

Parallel Circuits

Parallel circuits are used when the items in the circuit need to be turned on and off individually. Look for more than one switch.

Series or Parallel?

series

parallel

parallel

series

Electricity Symbols

In order to be able to draw complicated electrical systems, a set of symbols has been created that everyone can use and understand.

Circuit Diagrams

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

This is a symbol circuit with a battery, switch, and light bulb.

This is a circuit with two batteries, a switch and a motor.

Circuit Diagrams

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Above is a series and parallel circuit diagram.

seriesparallel

Picture Credits

The graphics in this slide show can be found at the websites below:http://www.bbc.co.uk/schools/ks3bitesize/science/physics/electricity_4.shtml

https://9arevision.wikispaces.com/electric+circuits

http://www.pge.com/microsite/pge_dgz/wires/concepts.html

http://members.shaw.ca/len92/worksheet.htm

http://www.explainthatstuff.com/electricity.html

http://www1.curriculum.edu.au/sciencepd/electricity/elec-circ.htm