Electricity and magnetism … But mostly magnetism

Magnetism A magnet is an object that can attract other objects that contain one of 3 elements: ______________

Which of these are magnetic?

Which of these are magnetic?

Very important aspect of magnets to remember… Magnets have opposite poles, called “North and South”. Opposites attract (likes repel) North and South attract North and North repel South and South repel

Very important aspect of magnets to remember… Magnets have opposite poles, called “North and South”. Opposites attract (likes repel) North and South attract North and North repel South and South repel

Could you separate the poles of a magnet?

Could you separate the poles of a magnet? No, you’ll just end up with smaller magnets, each still having a North and South pole. Why?

Why? To understand why, we need to think about what a magnetic metal (eg iron) looks like up close. You would see that it has many tiny sections called domains, which are essentially tiny magnets that each have N and S poles.

Domain arrangement Normally, domains in an iron sample are arranged in a chaotic order.

Domain arrangement But when bring this iron close to a magnet… Not magnetized Magnetized

Domain arrangement The stronger the magnet, the more aligned the domains will be. Not magnetized Strongly magnetized

3 types of materials Magnetic: An object with a magnetic field that can apply a force to another object near it.

3 types of materials Magnetic: An object with a magnetic field that can apply a force to another object near it. Ferromagnetic: A substance containing Fe, Co, or Ni, that can be attracted by a magnet.

3 types of materials Magnetic: An object with a magnetic field that can apply an attractive force to a nearby object. Ferromagnetic: A substance containing Fe, Co, or Ni, that can be attracted by a magnet. Non-magnetic: A substance that is not attracted to a magnet.

Magnetic Field A magnetic field is the area of space in which the magnetic force of a magnet can act on another magnet.

Most important thing to remember… Magnetic field lines always go from the magnet’s north to the south pole. Also good to know: The field lines don’t ever cross each other. They’re strongest at the poles (where the lines are closer together).

What happens when you bring a compass into a magnetic field?

Draw the arrows for this compass:

Field lines for 2 magnets:

Aurora borealis and australis Aurora borealis (northern lights) occurs when charged particles from the sun enter the Earth’s magnetic field field, causing them to glow. Why does this happen only in polar areas?