Series Circuit 1

• To build a series circuit, you will need three E10 lamp holders with bulbs, a size D battery with holder, three 9-inch pieces of copper bell wire with ends stripped and a 20-inch piece of copper bell wire with the ends stripped. Connect the lamp holders in a line, screwing the 9-inch pieces of wire into the screw terminals on the lamp holders. Connect one end of the 20-inch wire to the open screw terminal on the third lamp holder and the other end to the negative battery terminal. Connect the remaining short wire on the first lamp holder to the positive battery terminal. Because electricity flows in one direction, and the bulbs compete for energy, the bulbs will be dimmer the farther they are from the battery.
  
  

Series Circuit 2

• For this project, you will need a complete circuit consisting of three lamp holders with bulbs, three E10 lamp holders with bulbs, four 9-inch pieces of copper bell wire with ends stripped, 1 size D battery and holder that can accommodate 2 D batteries and a commercial knife blade switch. Observe the brightness of the bulbs in the complete series circuit. Add three more lamp holders to the string, using three 9-inch wires. What happens to the brightness of the bulbs? The more bulbs that are on a circuit, the dimmer the light. Add the knife blade switch to the circuit by connecting it between the long wire and the negative battery terminal with the remaining 9-inch wire. What happens when the switch is in the up position? What happens when you put the switch in the down (closed circuit) position? Observe the brightness of the bulbs. Change battery holders and add the extra battery to the circuit. When the circuit is closed, what happens to the brightness of the bulbs? With the circuit closed, remove one bulb from a lamp holder. What happens? The missing bulb broke the circuit.
  
  

Parallel Circuit 1

• To make a parallel circuit, you will need three lamp holders with bulbs, a size D battery in a holder, four 9-inch pieces of copper bell wire with ends stripped, two 20-inch pieces of copper bell wire with ends stripped and 1/2 inch stripped at 6 inches and 13 inches. Put the three lamp holders in a row. Connect short pieces of wire to each terminal on two of the lamp holders. Connect a long wire to each terminal of the remaining lamp holder. Bend the long wires toward the other two lamp holders. Connect the middle lamp holder to the stripped wire section at 6 inches of both long wires. Connect the remaining lamp holder to the stripped section at 13 inches of both long wires. It should look like a three-step ladder. Connect the remaining ends of the long wire to the battery terminals. Electricity flows following multiple paths in the branched design of the parallel circuit.
  
  

Parallel Circuit 2

• You will need a complete parallel circuit with three lamp holders and bulbs and a commercial knife blade switch. Remove one bulb from the parallel circuit. What happens? If a bulb burns out or is removed, the circuit is not broken, so the other bulbs remain lit. This is why household wiring uses parallel circuits. Add the knife blade switch in place of one of the lamp holders. What happens if you put the switch in the up position? Why?