The Earth itself is one giant magnetic force, and the magnesian stone is a naturally occurring permanent magnet. Magnets used in household objects and industrial processes are manmade, however, such as rare earth magnets, which are alloys of elements such as aluminum, copper and cobalt. There are two main categories of magnets: permanent magnets and induced magnets. Permanent magnets have a constant magnetic field surrounding them, while induced magnets only have magnetic properties when they come into contact with a permanent magnet.
Making your own magnet is a fun science experiment for kids keen to learn more about magnets and how they work. A really simple experiment is to create a small magnet that does not have a particularly large field of attraction. Find a permanent magnet, such as a refrigerator magnet, and gather a handful of tacks. Next, find a ferromagnetic object (an object that is strongly attracted to magnets but is not a permanent magnet itself) such as a large paper clip. Put a piece of paper onto a flat surface and place the clip on top. Using a swiping motion in one direction only, rub the permanent magnet over the surface of the clip. Repeat this movement 50 times. Place your tacks onto another sheet of paper, and hold your clip above them. If the experiment has been done properly, the tacks will attach themselves to the clip; the clip has become a temporary magnet.
Another way to create a magnet is to make an electromagnet. Find a large iron nail, copper wire and a D-cell battery. Wind the copper wire around the length of the iron nail, pulling it tight. Next, attach the copper wire to the battery: the lower end to the negative point on the battery and the higher end to the positive point. Use your creation to pick up the tacks. This electromagnet should work even after it has been taken away from the battery.
Electromagnets made from rare earth magnets are commonly used in manufacturing processes and in industry, for example as part of a crane picking up material in a scrap yard.
An interesting use of magnets is to encourage plant growth, known as biomagnetics. Back in 1862, Louis Pasteur carried out experiments on fermentation and discovered that the earth's natural magnetism affects plant growth. Seeds and water may be magnetized to help plants grow faster. A magnetizer improves seed germination by exposing them to the south pole of a manufactured magnet prior to sowing, although certain seeds--such as potatoes and carrots--grow better if exposed to the north pole of the magnet. This is because the types of starch molecules are different in certain seeds. Magnetized water is commonly used for irrigation as it improves the soil's fertility.