Magnets are materials that attract pieces of iron or steel. In ancient times, people first discovered magnetism when they found some naturally magnetic pieces of rock in the earth. They called

Here is the passage with the blanks filled in: Magnets are materials that attract pieces of iron or steel. In ancient times, people first discovered magnetism when they found some naturally magnetic pieces of rock in the earth. They called these rocks lodestone. Nickel, cobalt, certain types of ceramics and certain blends of metals can also make good magnets. Magnets have north and south poles. The north pole of one magnet will repel, or push away, the north pole of another magnet, and the south pole of one magnet will repel the south pole of another magnet. But, if you put the north pole of one magnet near the south pole of another magnet, you will feel an attractive force. You may have heard the saying