Magnetism

PhysicsMs. Allison

Agenda

• Engagement• Lecture• Demonstrations• Independent class work• Exploration• Closing

College Lecture

What can you record about magnetism?• Watch video• Record notes about important details• Magnetism Summary

What is Magnetism?

• Caused by moving electric charges • Charges interact with BOTH electric and

magnetic fields• 3 ways magnets can be created

What about Magnetic Domains?

• Microscopic clusters of aligned atoms• Align the atoms and make a new magnet

What are Magnetic poles

• One region on a magnet that produces magnetic forces

• North and south poles of every magnet• Opposite poles attract while like poles repel• Poles cannot be isolated

What are Magnetic fields?

• A force field around every magnet or current carrying wire

• Produced by motion of electric charges• Strongest near the magnet• Lines usually drawn from north to south

What is an electromagnet?

• A current carrying wire with many loops• Magnetic fields exert a force on moving

electrons in a loop• The magnetic field is strongest in the center of

the loop• Make with a wire, battery and nail

Solving for magnetic force and field

Magnetic field = force (charge)(speed)

B = F qv

Did you know the Earth is a magnet?

• Currents in molten part of Earth• Convection currents from heat of Earth’s core• Not stable

Magnets in today’s world

• Cell phones• Strips within cards• High speed trains

Closing

• How can one make a magnet?

• What happens to the electrons if a magnet exist or is made?

Homework

• Write 5 questions (with answers) about Magnetism