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