Electricity for the 4-H Scientist

by Eric B. Wilson

1. Lay out the board with a pencil and ruler as indicated in Figure 1.

2. Bend the three-inch nail as shown in Figure 2, using pliers, vise and hammer.

3. Pound the one-inch nails into the board for a half-inch at points A, C, and D. Use the three-inch nail to make a hole a half-inch deep at B. Put the crank nail in this hole and pound in a little farther. Attach the lamp socket brackets at E and F. Stretch the rubber band as in Figure 3.

4. Lay out the electricity path, the circuit (Figure 3). Use the black wire for the positive side of the circuit (the center pole of battery). Twist it around the switch crank B, and the center pole of battery. Run another piece to the outside terminal of bulb socket at E. Run white piece to negative pole of battery from the other terminal at E.

Figure 1 (Circuit Board)

Figure 2 (Switch)

5. Close the switch. The rubber band should hold the switch nail tightly against nail at C. Does the bulb light? __________ If it doesn't, check the connections.

Now you have a circuit—a closed circuit when the electricity runs all the way from the positive pole to the negative pole. The black wire is the hot side, the live wire, because it carries the full load of the battery up to the bulb.