Attractive: Can Electricity Produce a Magnet?
Can electricity produce a magnet?
- 1 yard (1 m) foil strip
- 16D iron nail
- 2 pencils
- sheet of typing paper
- duct tape
- 2 size D batteries
- iron filings (found in teacher supply stores or a hobby shop)
- new, clean penny
- short, wide rubber band
- Wrap the foil strip tightly around the nail. Neatly overlap the layers leaving about 6 inches (15 cm) of wire on each end.
- Lay the wrapped nail on a wooden table and lay both pencils perpendicular to the nail, one at each end.
- Cover the nail and pencils with the sheet of typing paper.
- Tape the two batteries together with the positive terminal of one touching the negative terminal of the other.
- Wrap one end of the foil around the penny. Tape the wrapped coin to the negative battery terminal and the second foil end to the positive terminal. Stretch the rubber band around the battery to hold the ends.
- While the foil ends are touching the battery terminals, sprinkle iron filings on the paper above the nail. Tap the paper gently to help the pattern form.
WARNING: DO NOT hold wire against battery terminals longer than 10 seconds. They can get hot and burn your fingers.
The iron filings form a pattern of lines around the nail.
The foil-like wires carrying a direct current are surrounded by a steady magnetic field (the area in which magnetic force—the push or pull around a magnet—can be detected). When an electric current flows through a coil of wire, the whole coil acts like a magnet. This type of magnet is called an electromagnet.
Winding the wire into a coil increases the strength of the magnetic field around the electromagnet. The iron nail becomes magnetized by the magnetic field around the wire, adding to the strength of the electromagnet. The iron filings are attracted by the electromagnet and they line up in the direction of its magnetic force field, forming a pattern.
- Would the amount of current flow affect the results? Repeat the experiment twice: first use one battery, and then use three batteries. As the number of batteries increases, the amount of current pushed through the wire increases.
- Does the number of times the foil is wrapped around the nail affect the results? Repeat the original experiment twice: first use foil 1.5 feet (45 cm) long, and then use foil 6 feet long (2 m). Be sure to wrap all the wire in the same direction. Science Fair Hint: A print of the iron filings pattern can be made by spraying a fine mist of white vinegar over the iron filings on the paper. Leave the paper undisturbed for several hours to allow the iron to rust. Turn the paper over and brush the rusty filings into the trash. The rusty marks leave a pattern of the magnetic field on the paper, which can be displayed as part of your project.
- Does the size of the core that the foil is wrapped around affect the results? Repeat the original experiment twice, first using a smaller nail, then using a larger nail.