Want to learn about magnetic fields? Sometimes the best way to learn is through visual representation, and this video shows you some funs ways to manipulate and view magnetic fields in action using a large horseshoe magnet, a steel keeper, plexiglass and some iron filings.
First you need some iron filings. The easiest way to get these is to use a hand file to file away bits of iron from an iron bar or iron pipe. Basically, find any piece of iron or steel that a magnet will stick to and file some bits from it. Next, to keep things clean, put a sheet of clear plexiglass or even a thin piece of wood or cardboard above a magnet. Put the iron filings on top of the sheet. Now move the magnet around below the sheet and you can see how that causes the iron filings to move above the sheet. Look for some of the effects demonstrated in this video.