# Electromagnetism

Reference - Forumla Sheet

## Content Overview

Activities

Seeing Magnetic Fields Lab - Take a look at the magnetic fields you've put together using magnets and iron filings. Then move the magnets around to see how it all changes!

Electromagnetic Induction Demo - What's going to happen when a magnet passes over some wire?

Faraday's Law PhET Simulation - What's the best way to make the most electricity, and what type of current is it going to be?

Magnet in Copper Tube Demo - Showing how Eddy currents directly affect the rate of motion

Build a Speaker Project - Given magnet wire and some magnets, what kind of speaker are you going to build?

Thunder Ball Demo - Plasma ball interactions

Topics

Electromagnetism and Ferromagnetism

Magnetic Field & Field Lines

Electromagnetic Induction

Eddy Currents

Plasma (State of Matter)

## Students are Expected to Understand

Interactions between Magnets and Their Fields

How to Construct and Use Electromagnets along with Further Applications

### Some Notes on Electromagnets

• The polarity of magnets are known as North and South
• Opposing polarities attract. Like repels
• Ferromagnetsm is caused by a nearby magnetic field. They have domains which must be lined up increase magnetic field strength
• An electromagnet's strength is determined by how much current is flowing through and how much wire it is exposed to. That's why we often loop wires!
• Electromagnetic induction is a way of saying that when a magnetic field changes, electricity is made. The strength of the current depends on how big a change there is in the magnetic field. You can change the field strength or direction
• Eddy currents are caused by moving a magnet near a conductor. Moving the magnet changes the magnetic field, and the conductor now has a current that creates an opposing magnetic field slowing the magnet
• Plasma, a higher-energy state of matter, has properties that make it electrically conductive and magnetic