Magnetic fields are an area of fascination for students of all ages, and third graders are often introduced to the basics of this captivating subject. Students in this grade learn that magnets attract certain substances and repel others, and you can help your third grader produce a science fair project with common materials to demonstrate his or her understanding of these concepts.
Create a Collection
One form of science fair projects you can help your child create is a collection of highly magnetic, weakly magnetic and magnetically repulsive substances. Help your child collect samples of different examples of highly magnetic metals such as iron and steel hardware. Include a section of extremely mild magnetic metals such as copper and silver. Finally, add a section of seemingly nonmagnetic materials such as wood and plastic and cloth. Glue each sample to a sheet of poster board, and beneath each sample, glue an index card on which your child can write a brief description of the object and how magnetic it is.
Build an Electromagnet
You can help your child demonstrate how electricity plays a role in magnetism by building an electromagnet. You'll need a steel bolt, about two feet of thin copper wire, a nine-volt battery and some masking tape. Wrap the bolt with tight coils of wire, but make sure to leave at least eight inches of copper wire left unwrapped at each end of the bolt. Connect each end of the wire to a terminal on the battery, and secure each one in place with a piece of masking tape. Once you have connected both ends of the wire, the bolt will be electrified and therefore magnetized. Your child can then demonstrate magnetism by exposing the bolt to paperclips and other small, magnetic metals.
Construct a Compass
You can help your child build a compass that he or she can actively demonstrate in front of the people who attend the science fair. You'll need a large bowl of water, a fairly strong magnet, a cork and a paper clip. Have your child straighten the paperclip and rub it against the magnet for a minute. Then, have your child stick the paperclip into one end of the cork, and set the cork in the bowl of water. The cork will float, and the paperclip will point itself in one clear direction. This direction is North. The paperclip will remain magnetized for only a few minutes, so your child can repeat this process over and over for people at the science fair.
Display Magnetic Fields
Third-graders can illustrate the lines and directions of magnetic fields by using a magnet, a piece of white poster board and either iron filings or iron powder. Have your child set a fairly strong magnet onto a table, and lay the piece of poster board on top of it. You might need to place small object underneath the corners of the poster board to keep it flat. Next, sprinkle the iron filings onto the poster board and watch how they collect around the magnet. They will form distinct lines that illustrate the magnetic field. You can also use two magnets, and see how their fields interact when they either attract or repel.
- Brand X Pictures/Stockbyte/Getty Images