Download magnets - Elkhorn Valley Schools

MAGNETS
• Magnetic forces – Invisible forces that pull 2 magnets
together
• A magnetic field surrounds all magnets (we call these
magnetic field lines)
Magnetic poles (N+ and S-)
• The area where the magnetic force is greatest
• Don’t forget…like poles repel each other!!!
Earth’s magnetic poles
• Magnetic North is off from “geographic” North…why???
• Some think it’s due to Earth’s internal heat
What minerals are magnetic?
• Iron
• Cobalt
• Nickel
Magnetic domains
• Groups of atoms with similar aligned poles
• Nail (temporary) vs. permanent magnet
• How can magnetism be reduced?
• Being dropped or heated
• Don’t forget…break a magnet,
• and you now have 2!
Electricity and magnets
• Moving charges produce a magnetic field (or force)
• The greater the current, the stronger the field (or force)
Electromagnets
• A magnetic element wrapped in wire
• This creates a magnetic field around the wire
• How do you create a stronger electromagnetic?
• Increase the loops
• Increase the amount of iron
• Increase the current
• What all uses these things? All electric motors
• Let’s talk about how a stereo speaker works…