Magnets and Magnetic Fields

1. Magnets and Magnetic Fields Magnetic Forces

2. Magnetic Forces • Is the force a magnet exerts on another magnet, on iron or a similar metal, or on moving charges. - acts over a distance and varies over a distance as well.

3. Magnetic Forces • Magnetic Poles: two regions where the magnet’s force is strongest. The one is the North and the other is the South. • The direction of magnetic force between two magnets depends on how the poles face. • Like magnetic poles repel one another, and opposite magnetic poles attract each other.

4. Magnetic Fields • Magnetic Field: surrounds a magnet and can exert magnetic forces. • A magnetic field, which is strongest near a magnet’s poles, will either attract or repel another magnet that enters the field.

5. Magnetic Field Around the Earth • Magnetosphere: The area surrounding earth that is influenced by this field. • Geographic North pole is 90 degrees. • Magnetic North pole is 81 degrees North.

6. Magnetic Materials • Iron, Nickel, and Cobolt have strong magnetic fields. • Magnetic Domains: is a region that has a very large number of atoms with aligned magnetic fields. • Ferromagnetic Material: such as iron, can be magnetized because it contains magnetic domains. • When a material is magnetized, most of its magnetic domains are aligned.

7. Nonmagnetized Materials • Just because something is ferromagnetic doesn’t mean that it is magnetized. • If the domains of the material are not aligned and they are randomly aligned, the magnetic capabilities are cancelled out.

8. Magnetized Materials • Some materials can become magnetized by being placed in the magnetic field of another magnetic, but it then loses it magnetic capabilities. This is known as a temporary magnet. • When a material holds it aligned domains for longer periods of time, it is known as a permanent magnet.