MAGNETIC ATTRACTION

• An object that attracts certain kinds of metals, especially iron, is called a magnet. The area near the magnet where the magnet can act to attract things is called its magnetic field. The farther away from the magnet an item is, the weaker the magnetic field is, and the less likely an object is to become attracted to the magnet.
• Magnets can be either permanent or temporary. A permanent magnet stays magnetized for a long time. A temporary magnet loses its magnetism after only a short time. You can even turn something made out of iron into a temporary magnet by rubbing it against a permanent magnet. The more you rub, the stronger the magnet is that you create. However, the effects will wear off over time. 
• The two ends of the magnets are called magnetic poles. The poles, which are found at the ends of bar magnets and the tips of the horseshoe magnets, are the strongest parts of the magnet. Each magnet has a north pole and a south pole. Opposite poles attract each other (pull toward each other), and same poles  repel (push away from each other). So a north pole and a south pole will pull toward each other, and two norths or two souths will push away from each other. If you are holding the magnets, you can actually feel the push and pull effects of magnetism. 
• A special kind of temporary magnet that uses electricity to create a magnetic field is an electromagnet. An electromagnet can be an extremely strong magnet, but it only acts like a magnet when it is receiving electrical current. A stronger electrical current will produce a stronger magnet. Unlike other magnets, an electromagnet can be controlled by a switch. As soon as the switch is flipped to turn off the electrical current, it loses its magnetism and drops whatever had been attracted to it. This technology is used to operate large cranes that lift heavy metal object, such as cars. Electromagnets are also used to make motors run in small appliances. The combination of regular magnets and electromagnets makes it possible for electrical energy to be turned into energy of motion. Thanks to magnets, we have things like fans and refrigerators!

Name:__________________________________

Answer the following questions based on the reading passage. Don’t forget to go back to the passage whenever necessary to find or confirm your answers.

1)   Explain the difference between a temporary magnet and a permanent magnet.

   2)   Would the pull of a magnet be stronger at its north pole, or at the middle of the magnet? How do you know?

   3)   Why is an electromagnet unique?

   4)   What do we use electromagnets for?

   5)   List as many appliances as you can think of that use energy of motion.