介绍:
Let's go fishing with a magnet.
Put different things in a box: a penny, a nickle, a dime, a twig, some tacks and paper clips, bits of aluminum foil, rubber bands, pieces of paper, and a pin or two.
Next, find a magnet. They come in different shaps and sizes.
Tie one end of a string around your magnet. Tie the other end to a stick or a pencil. This is your fishing pole.
Go fishing in the box. Put the things you "catch" in a pile. The others will stay in the box.
Everything you lifted out of the box is made of iron: the tacks, the paper clips, and the pin. The magnet won' t pick up a twig, rubber bands, aluminum foil, paper, a dime, a nickle, or a penny because they are not made of iron. Dimes, nickles, pennies, and aluminum foil are made of other kinds of metal. A magnet picks up only things that have a lot of iron in them.
You can make your own magnet with a needle. Needles are made of steel, which is mostly iron.
Hold the eye of the needle.
Stroke the needle along one end of the magnet.
Move along the magnet in only one direction: from the eye of the needle to the point, not back and forth. Do this twenty or thirty times.
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