It’s been a while since we actually did any science experiments, but recently I bought a magnet science kit that was only $7 (at a Tuesday Morning store). It was called Power of Magnets from Think Box so we decided to play with it last night.
I try really hard not to buy science kits unless I think they are worthwhile. This kit contained 3 ring magnets and a stand for them, a horseshoe magnet and a bar magnet, a metal bar and copper wire, a compass and a small toy ball maze and a ruler and piece of felt.
We first played with the ring magnets on the stand. Depending on which way you stack the rings, they either stick together (because opposite charges attract) or float on top of each other (because like charges repel each other).
After the girls played with the different magnets for a while and doing some of the simple magnet tricks, I decided to make an electromagnet. An electromagnet is a type of magnet which is created only by the flow of electric current that is applied to it. Because the copper wires connected to the battery got really hot, and sometimes created a spark if they shifted off, I decided to make this one simply a demonstration for them.
It’s a lot easier than I thought it would be. The hardest part was keeping the wires attached to the battery. The tape didn’t hold very well.
We took the metal bar that came with the kit, wrapped the copper wire tightly around it and attached each end of the wire to each end of a C-battery with tape
It was pretty cool to see that it worked.
According to Wikipedia
A wire with an electric current passing through it, generates a magnetic field around it, this is a simple electromagnet. The strength of magnetic field generated is proportional to the amount of current.
Current (I) through a wire produces a magnetic field (B). The field is oriented according to the right-hand rule.
In order to concentrate the magnetic field generated by a wire, it is commonly wound into a coil, where many turns of wire sit side by side. The magnetic field of all the turns of wire passes through the center of the coil.
The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be rapidly manipulated over a wide range by controlling the amount of electric current. However, a continuous supply of electrical energy is required to maintain the field.
Would you like to make your own electromagnet? There’s some easy instructions for an electromagnet over at Science Bob’s website using a battery, thin-coated copper wire, and a steel nail and some paper clips.