Magnets and Magnetism Magnet – any material that attracts iron or things made of iron

Properties of Magnets 2 opposite poles Magnets exert forces on each other Magnets are surrounded by a magnetic field

Magnetic Poles Each end of the magnet is a magnetic pole. Magnetic Poles are points on a magnet that have opposite magnetic qualities. Magnets have a north and south pole

Magnetic Forces The force of attraction or repulsion caused by moving (spinning) electric charges. Opposite poles attracted Like poles repel

Magnetic Fields The region around the magnet in which magnetic forces act.

Causes of Magnetism Electrons in certain materials move in such a way that it make a magnetic field. The atoms will then have a north and south pole. In iron, nickel, and cobalt groups of atoms are in tiny areas called domains. Domains are like tiny magnets of different sizes within an object. The arrangement of domains in an object determines whether the object is magnetic.

Domains & Alignment

Losing Alignment Magnets lose their strength when their domains no longer line up. Dropping a magnet Entering into a stronger, opposite magnetic field Increasing temperatures

Make a Magnet You can make a magnet from something made of iron, cobalt or nickel A nail can be magnetized by dragging a magnet down it several times to line up the domains

Cutting a Magnet When magnets are cut in half, they end up with a North and South Pole because the domains are lined up.

Kinds of Magnets Ferromagnets- magnets made of iron, nickel, cobalt and have strong magnetic properties. Electromagnets- magnets made by an electric current and usually has an iron core.

Temporary & Permanent Magnets Temporary – Easy to magnetize Permanent – Difficult to magnetize

Earth as a Magnet Imaginary magnetic bar running through the earth, point to North and South Poles. Compass used to tell direction. Earth’s Geographic poles are the axis on which the Earth rotates.

Core of the Earth Core is made of a solid iron/nickel inner core and a liquid outer core. As the earth rotates, the liquid core flows. Electric charges move, which makes a magnetic field.

Magnetic Light Show The Aurora is formed when charged particles from the sun (electromagnetic energy) hit oxygen and nitrogen atoms in the air. The atoms become excited & give off light of many colors. Northern Lights & Southern Lights