Electromagnets love iron too
The horseshoe-shaped electromagnet in the kit is even stronger than your
homemade electromagnet. But the construction is very similar: two
spools mounted on a U-shaped iron core. See how it works!
HERE’S HOW
Connect the horseshoe electromagnet to the battery via the push button
switch and two plug wires (figure 1). Before turning it on, hold a few
pieces of iron (screws or a nut, for example) in front of the bare metal
prongs. You won’t feel any pull at all.
Now press briefly on the button to make current flow through the horse-
shoe. The pieces of iron will be attracted to it.
What happens to the iron pieces sticking to the magnet when you switch
the current off?
Test the strength of the magnet. How close do the iron pieces have to get
for them to react? Are both poles equally strong?
Try carrying out the experiment using the colorful disks (figure 2).
EXPERIMENT 54
54
WHAT’S HAPPENING
The horseshoe electromagnet real-
ly does turn into a magnet — an
electromagnet — when current
flows through it. Then it attracts
iron just like a permanent magnet.
But it only does so while the cur-
rent is flowing. Turn it off, and the
electromagnet loses its power.
1
2
Summary of Contents for Electricity and Magnetism 620417
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