This SEED Engineering Challenge is to build the best electromagnet you can. Your electromagnet will be judged by how much weight it can lift so the “best” electromagnet is the one that lifts the heaviest object or objects.

As with any engineering problem, there are limitations and requirements you must meet. Here are your guidelines:

1. You may use a maximum of 250cm of wire. There is no minimum.
2. The wire must be no less than 20 gauge. (The higher the gauge, the thinner the wire, so 20 gauge is the fattest wire you may use.
3. You may use anything for the core, or no core at all.
4. The electromagnet may be of any shape or size.
5. Your power source must be a single 1.5 volt battery, no larger than D size.
6. You may use any ferromagnetic material, such as iron, nickel or steel, as the weight you are lifting. You can try to lift a single object, or may small things such as paper clips or nails. It’s the total weight that counts.

After you’ve built your electromagnet send us pictures and a description of what you did along with your results. We’ll publish them here in the SEED Science Center.

Safety

1. Use only a single 1.5 volt battery, no larger than D size, as specified. Higher voltages can cause electric shock and a larger battery, even if it is only 1.5 volts, can cause dangerous overheating of some electromagnets.
2. Even with the precautions in 1, your electromagnet may get hot. If this happens, disconnect it immediately.

Find Out More

What is an electromagnet?
Look at how we built and tested our electromagnet.
Need some tips and suggestions?
Check out these related links.

What Is an Electromagnet?

When electricity flows through a wire, a magnetic field is produced. Most electromagnets consist of wire that is coiled around a core made of iron or steel. Here’s an example that we used in the Magnetic Relaxation Experiment.

The wire is wound around a straightened paper clip and is attached to one end of the battery. When the loose end of the wire is touched to the other end of the battery, electricity flows through the wire and the paper clip becomes magnetized.

This happens because the iron atoms in the paper clip are arranged in clusters known as domains. These are like little magnets, each with a north and a south pole. They are usually jumbled up and pointing every which way so their magnetic fields cancel each other out. When the domains are all lined up in the same direction the piece of metal is a magnet. When electricity flows through the wire that is coiled around the paper clip, the domains line up.

Another type of magnet is a permanent magnet, such as the ones you might stick on your refrigerator. A permanent magnet is made of iron or another ferromagnetic metal such as nickel or cobalt. The domains are lined up when the magnet is manufactured and stay that way.

PDF Version of this Engineering Challenge

Related Links

Magnetic Relaxation

The nuclei of some atoms can be made to line up with a magnetic field. When that field disappears the nuclei "relax," returning to their previous state of alignment. Here's an experiment you can do to get a feel for how this works.

Nuclear Magnetic Resonance Six Miles Deep: Physics in the Oil Industry

What type of measurement can identify molecules, make images of the interior of the human body and measure how fast fluids can flow through porous rocks?