Today we created a working telegraph. It's a simple concept, really. We had a kit.
Create an electromagnet by winding wire around a nail. Attach one end of the wire to a battery (with a big rubber band), and the other end to a paperclip attached to a brad on a piece of cardboard. Bend the wide end of the paperclip up so it makes a switch you can press down...onto a second brad. Attached to this second brad is another wire going to the other end of the battery. Insulated, except for the contacts, of course.
The thing about electicity is that it always is a circut, either open (off) or closed (on). When you flip a light switch, you are either opening the circuit to turn the light off, or closing it to turn it on. Same with an appliance plugged into the wall. You tap into a circuit and then close it by flipping your hair dryer switch...and the motor starts.
The thing that makes it a telegraph, is the the electromagnet (nail wrapped in wire) is sticking into a foam block. Next to it is a paper clip with one end straightened and the other end bent and hovering over the top of the nail, also sticking in the foam block. When the circuit is closed, the paper clip taps the top of the nail because it is magnetically attracted to the electromagnet.
Pretty cool, huh?
Then we played with morse code.
Last night two of my kids made a working motor all by themselves. Wouldn't it be nice if the motor could actually DO someting besides wiggle? Perhaps someday we can take these concepts and figure out a way to hook the TV up to a stationary bicycle.