What to Do
1. Make a simple kind of direct-current meter that will show you that there's a magnetic field around a wire carrying an electric current and that will detect a very tiny current.
2. Make a more refined D.C. instrument (galvanoscope) and measure the voltage of different sizes of dry batteries, and show how an electric current can be induced.
Tools and Materials You'll Need:
Pair of pliers, knife, small hammer
30 feet of No. 24 bell or magnet wire
Compass
Two coins—a penny and a dime
Fine sandpaper
Blotting paper
Plastic or cellophane tape
Wooden blocks (See Figure 4)
Glue
2 small nails
One #905 dry cell, a penlight battery, and two regular flashlight batteries
Table salt
Drinking glass
2 paper clips
Two machine bolts