A galvanometer is an instrument that detects electrical current. You can easily make one at home with items you may have lying around your house. All you need is a match box (or other small box) that is large enough to house a compass, a compass, tinfoil, and a D battery.
Take the ends and connect to the terminals of a D battery. Watch the needle of the compass move. The battery emits electrons that run through the aluminum foil (your conductor). When electrons move they create a magnetic field which moves the compass needle.