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### Course: Middle school physics>Unit 2

Lesson 7: Electromagnetism

# Electromagnetism

Moving electric charges create magnetic fields in the space around them. These magnetic fields can be used to generate magnetic forces. Oppositely, when magnetic fields are changed around charges, they can create moving electric charges, or electricity. Both of these phenomena are called electromagnetism, which is used in everyday items, from motors to medical scanners. Created by Khan Academy.

## Want to join the conversation?

• How can a magnetic field have direction? Are there particles around a magnet that move in one direction or other?
• A magnetic field can have direction because the particles that surround it are either moving in the north or south direction
• What would happen if you put permanent magnet close to a electric magnet, would the electric current change directions.
• If you put a permanent magnet close to an electromagnet, it can indeed affect the direction of the electric current flowing through the electromagnet
• How do you know the direction of a magnetic field?
• The direction of the magnetic field around a coil can be determined by using the right-hand rule. Place your right hand around the coil with your thumb pointing in the direction of the current flow, your fingers will curl in the direction of the magnetic field.
• What determines the strength of a permanent magnet?
• A magnet's strength is affected by its size and the material it is made of. The environment also affects it (e.g. surrounding temperature).
• How does a spinning magnet cause an electric current? Not sure I fully understand the mechanics
• When a magnet spins near a wire, it creates a changing magnetic field. This changing field induces an electric current in the wire through electromagnetic induction.
• Does this mean that everything that has electricity in it is also a magnet? My toothbrush?
• Technically not, it would be magnetic from the metals, but not a magnet. Electromagnets are very specific on what metal they are wrapped around, and how many coils, so i do not think that a toothbrush would be considered a magnet.
• How do you change the direction of the electricity on a coil (thus, changing the direction of the magnetic field)? Do you just loop it in the other direction? (instead of looping it in a clockwise motion, you do it counter clockwise?)