ELECTRICITY AND MAGNETISM But mostly magnetism Magnetism A
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 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, causing them to glow. ◦ Why does this happen only in polar areas?
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