Classroom Materials

Learn how to reveal iron hidden in your food
You may think of it largely in terms of lawn furniture and vitamins, but iron is everywhere. Not only is iron the fourth most common element in the earth's crust, it's also an essential part of our own blood!

Electricity and magnetism together make a circuit
Electricity and magnetism are best buddies. Magnets can be used to make electricity, and electricity can be used to magnetize objects. Essentially, everything that operates via electricity gives off its own small magnetic field, and when the object is unplugged, the magnetic field stops.

A magnet that drips: making ferrofluid
A ferrofluid is a special liquid with tiny magnetic particles floating around inside. Since these particles are attracted to each other, they must be coated with a special substance that prevents them from sticking together (so that the ferrofluid remains fluid). What makes ferrofluid so special is that in the presence of an outside magnetic field, each of the tiny particles becomes magnetized and the ferrofluid condenses into a solid.

Follow the needle: making a compass
Every magnet you'll see has a north-seeking and south-seeking pole, just like the Earth, which is basically a giant magnet. If two magnets are brought together, the north pole of one will attract the south pole of the other. This is why compasses work on the Earth.

A portrait of magnetism: drawing magnetic field lines
Magnets have two poles; the field lines spread out from the north pole and circle back around to the south pole. In this activity, you'll watch field lines materialize before your very eyes. The invisible will be made visible thanks to a handful of tiny iron filings.