You've just done 2 things! First, you've built an electrical
circuit. "Circuit" sounds like "circle" because they're both from the Latin root "circ-" which means "circle".
Electricity from the battery travels in a circle - as long as
the circle doesn't have a gap in it! A gap is called a "short". That's where we get "short circuit".
Second, you've made an electromagnet. It's only a magnet
when electricity is actively running along the wires.
Once you've connected everything, test by sliding the paperclip
to connect the 2 screws that are the switch. When electricity travels along a coil (your wire-wrapped nail), it creates
a magnetic field. Touch a paperclip to the head of the nail. When the switch is connected (on), the clip should
"stick" to the nail head. It'll fall off when you slide the paperclip switch away from the screw (off).
If it doesn't work, that means there's a short in your circuit. Someplace, the wires
or clips are not totally touching each other or they're not touching the battery securely. So, go around
your circuit and tighten it. Make sure ALL of the connections are touching very well. Try touching the switch's
paperclip to different spots on the switch's screw. Also, it could be that the battery has lost its power.
You can replace the battery the same way you installed the first one. Don't leave the switch on, or it will overheat
the battery and use it up!
Now for some thoughts: This could be the start of a great science fair project! (I
know. Every year I'm a science fair judge all around the Metroplex!) So keep a lab notebook where you write all
the things you think of or try out - it'll really set your project apart from the rest!
What if you wound TWICE as much wire around the nail? (What about 3 or 103 times
as much?) You can buy wire at Radio Shack or the hardware store. The type of wire we used is "16 gauge bell wire".
It's pretty cheap!
Speaking of wire, what if you changed the size or type of wire?
What if you changed the size of the nail?
What if you added a second battery? (Or a 3rd?) How would you add another battery to your
circuit? Look up the words "parallel" and "series" in a book about electricity and circuits.
What if you added a different type of battery? (Like "AAA, C, D, 9-volt".)
How could you test your electromagnet's power? (hint: wonder how many paperclips or washers or
little metal pieces it can pick up?)
Could you use this circuit to power another device?
I hope you have lots of fun with your electromagnet circuit. I also hope you'll discover
that it's TONS of fun to make projects like this!