Physics:Magnets and Electricity
Scientists believe that inside magnetic materials there are tiny little regions called domains. Each domain acts like a minute magnet with both a north pole and a south pole. In an unmagnetized piece of iron the domains are randomly scattered， so there's no overall magnetic effect. But in a magnet the domains are all made to line up with the north poles at one end and the south poles at the other. We'll also learn something about electromagnetics in this program.
- Added：2006
- Country：Australia
- Duration：23
- Time of update：2011/8/15 15:22:27