What is magnetism? The force of attraction or repulsion of a magnetic material due to the arrangement of its atoms, particularly its electrons. The earliest magnets were found naturally in lodestone used by the ancient peoples as compasses. Magnets produce magnetic forces and have magnetic field lines that show the location of the magnetic field

Magnets have two ends or poles, called north and south poles Magnets have two ends or poles, called north and south poles. At the poles of a magnet, the magnetic field lines are closer together showing that the magnetic forces are the strongest Unlike poles of magnets attract each other and like poles of magnets repel.

The earth is like a giant magnet! The nickel iron core of the earth gives the earth a magnetic field much like a bar magnet. Notice that geographic north and magnetic north are on opposite sides of the Earth. A compass needle is a magnet – it is attracted to the southern magnetic pole of the Earth which is found at geographic north.

What are magnetic domains? Atoms themselves have magnetic properties due to the spin of its electrons. Groups of atoms join so that their magnetic fields are all going in the same direction These areas of atoms are called “domains” When an unmagnetized substance is placed in a magnetic field, the substance can become magnetized when the domains line up in the same direction.

Electricity and Magnetism – how are they related? Use the Right hand rule to determine the direction of the current or magnetic field. Imagine your right hand curled around the wire, your thumb points in the direction of the current and your fingers show the direction of the magnetic field

What is an electromagnet? When an electric current is passed through a coil of wire wrapped around a metal core, a very strong magnetic field is produced. This is called an electromagnet. The more coils wrapped around the core, the stronger the magnetic field that is produced. This stronger magnetic field leads to a stronger current

What is a galvanometer? A galvanometer is an electromagnet that interacts with a permanent magnet and acts as an ammeter to measure current. Galvanometers are used as gauges in cars (part of the speedometer and odometer)

What are electric motors? An electric motor is a device which changes electrical energy into mechanical energy.

How does an electric motor work? Go to the next slide 

What is electromagnetic induction? We have seen how electricity can produce a magnetic field, but a magnetic field can also produce electricity! How? What is electromagnetic induction? Moving a loop of wire through a magnetic field produces an electric current. This is electromagnetic induction. A generator is used to convert mechanical energy into electrical energy by electromagnetic induction.

Quiz Grade Page 592 Define all terms Answer review questions 2, 3, 7, 9, 10 Answer think and explain question 36 Answer think and solve question 40