Fremont Magnet Elementary

• Magnets have two poles, north and south.

• A magnet's force is strongest at the poles (the ends)

• Like poles repel

• Unlike poles attract

• Not all metals are magnetic.  It must contain iron to be magnetic.

• The Earth is like a giant magnet.  It has a north and south pole.   The Earth has an invisible magnetic field that surrounds it, just like a magnet.

Click here for a brainpop movie about magnets

Click here to see the lesson about magnets

Can you answer these questions?

This picture shows two bar magnets set down next to each other.  What will most likely happen?

  Each magnet will turn from horizontal to vertical, with N up
  The magnets will repel each other
  The magnets will attract each other
  Nothing will happen until a current is switched on

If two objects both have a negative charge what will they do?

  They will attract toward each other
  They will repel away from each other
  They will do nothing

You can sprinkle iron filings around a magnet.  Where will the iron filings be most concentrated?

  at the source of the current
  at the poles
  toward the magnetic switch
  toward the center of the magnet

2. Electromagnets and Generators

 Here are a few facts about electromagnets and generators...

• You can make a magnet using electricity - called an electromagnet
  
  
  
  
  
   

• You can make electricity using a magnet - called a generator 
  
  
   

• There are 3 ways to change the strength of an electromagnet: 

  • wind wire around an iron core, like a nail

  • add more winds to the coil

  • increase the battery power

• Electromagnets are used in things like: fans, doorbells, washing machines, and dryers.

Click here to watch a brainpop movie about Electromagnets

Click here to go to the lesson on Electromagnets

Can you answer these questions?

If a magnet is moved back and forth inside a coil wire, what will happen?

  The force of the magnet becomes greater
  The magnet loses its magnetic properties
  The coil of wire grows very hot
  The motion creates an electric current
 

Which of these is the main characteristic of electromagnets that makes them useful in simple tools, such as hair dryers and doorbells?

  They can be very strong
  They cannot transmit electricity
  They can be switched on and off
  They can be made of plastic
 

Which does not affect the strength of an electromagnet?

   adding water
  size of the nail in the core
  amount of current from the battery
  number of coils of wire

3. Circuits

Here are a few facts about circuits...

• For electricity to flow the circuit must be complete or closed.
• The flow of electricity is called current
• The current flows in 1 direction
• If you reverse current it will flow in the opposite direction.  For example, if you flip the battery the current will go the other way.
• Electrical current makes a magnetic field

Click here to watch a brainpop movie about circuits

Click here to go to the lesson on circuits

Can you answer these questions?

This shows some electric devices on a circuit.  On this circuit, which of the devices will work?

  only the fan
  the lights and the doorbell
  only the light
  the light, the doorbell, and the fan
 

The picture shows a fan spinning clockwise.  What would happen if the current changed direction?

  it would spin faster
  it would spin slower
  it would spin in the opposite direction
  it would not change

4. Converting Electricity

• Electricity can be used to heat, move, or light things.

  Heat	Light	Motion

Can you answer these questions?

Which of the following performs its function by converting electrical energy to motion?

Which of the following converts electric energy to heat and motion?

  electric fan
  flashlight
  hair dryer
  electric iron

6. Static Electricity?

Here are some things you need to know about static electricity...

• You can move electrons from one thing to another by rubbing, like shuffling your feet across the floor.
• You get shocked when you touch a doorknob because the extra electrons are pulled toward the protons in the metal.

• An unequal amount of electrons causes 2 objects to attract

• An equal amount of electrons causes 2 objects to repel

Click here to go to the lesson on static electricity

Can you answer these questions?

Why can you get a shock if you touch a metal doorknob after walking across a wool carpet?

A child rubbed two balloons with a piece of wool.  What will happen when the balloons are brought near each other?

  the balloons will repel each other
  the balloons will attract each other
  the balloons will become positively charged
  the balloons will pop

Now try taking the online test

How Static Electricity Works

*Electricity Games

TechTopics Electricity