Magnetizing Metals: The Magnetic Nail
In magnets, the electrons of atoms are lined up so that they are all spinning in the same direction. This group of aligned atoms is called a magnetic domain. In nonmagnetic materials the electrons are oriented in different directions. Some materials, such as pieces of iron, can be temporarily magnetized with a bar magnet, which can line up the domains in the same direction. In this activity you will use a bar magnet to magnetize an iron nail so it becomes a temporary magnet.
Large iron nail; Three metal paper clips; Bar magnet; Safety glasses
- Pick up the nail and touch its pointed end to one of the paper clips. Is the paper clip attracted to the nail?
- Hold the head of the nail in one hand. Gently stroke the nail with the bar magnet thirty times.
- Put down the bar magnet and attempt to pick up a paper clip with the nail again. What happens?
- Attempt to pick up multiple paper clips with the nail. Is this possible?
- Put on your safety glasses and drop the nail so that it strikes the floor.
- Pick up the nail and attempt to pick up the paper clips.
- Were you able to pick up a paper clip in step 1? Explain why or why not.
- Were you able to pick up any paper clips in step 3? Explain why or why not.
- Were you able to pick up paper clips in step 6? Explain why or why not.
- No. The nail is not magnetized at this point.
- Yes. The nail had been magnetized with the bar magnet.
- No. Dropping the nail on the floor caused the orientation of the magnetic domains to be altered. When dropped on the floor, the iron atoms no longer all pointed in the same direction and the magnetic effect was lost.
Determine whether the number of times you stroke the nail with a bar magnet affects the quality of the temporary magnet produced. Also try to magnetize some other substances besides a nail.