1. Magnetism Notes #2

2. Mr. Magnetism?

3. What if the magnet broke? What happens? *Although magnets ___________ and ___________ each other, the DO NOT have __________ poles! You get more magnets! (each piece now has a north and south pole) attractrepel + or -

4. Creating a MagnetHow to magnetize an object: To make a strong magnet: To make a weak magnet: How do you make a compass? Heat up the ferrous object and let it cool in the presence of a magnetic field. When completely cooled, it will be magnetized. (For example: ancient clay pots & lava) Let a ferrous object sit in the presence of a B- field Balance a bar magnet on a point so that it can spin freely

5. Ancient Clay Pots What do we use ancient clay pots for? We collect data from these pots in order to chart the decline of the Earth’s magnetic field.

6. Magnetic Field Reversals End of the world??? Using data from cooled volcanic lava, we know that it reverses about every 200,000 years. The last reversal was 780,000 years ago!

7. Destroying a Magnet What does it mean to demagnetize something? How do you do it? To make the e- spins of all the domains random 1.) Influence it by an outside magnet 2.) Hit it with an object or drop it 3.) Heat it up

8. Electric Current How does electric current relate to magnetism? So what would happen to a compass that is placed on a wire with current flowing through it? Electric current flowing through a wire generates a looping magnetic field around the wire. It would be influenced by the magnetic field and no longer point towards north

9. Car ExampleSolenoid: What is it? How does it work? Why is it bad if your car battery dies? In a car or truck, the starter solenoid is part of the starter system. The starter solenoid receives a large electric current from the car battery and a small electric current from the ignition switch. When the ignition switch is turned on, the small electric current forces the starter solenoid to relay a large electric current from the battery to the starter motor.