Have you ever been to a party that was lit up by the strings of overhead lights? Sets of these lights hang as holiday or patio decorations. As you may have observed, some of these light sets are hooked up in a special way. When one bulb goes out, the others remain lit! This way of wiring makes it much easier to identify the burned-out bulb. Otherwise, you’d be faced with testing the entire set.
Things Required:
Two “D” cells in battery holders
Two torch bulbs in lamp holders
Connecting wires with each end stripped 1½ inches bare of insulation
Switch
Directions:
Assemble the setup shown below.
Close the switch. What happens? Do both bulbs light? Is one bulb brighter than the other? In this circuit, how many different paths can the electrons flow through?
Keep the switch closed. Unscrew one of the bulbs. What happens? Can you explain your observations?
Draw a diagram of this circuit using the symbols presented earlier. Use this diagram to describe the flow of electrons.
This Is What Happens:
The circuit you built is called a parallel circuit. It offers more than one path for the moving charges. This circuit had two possible paths. The current of flowing electrons split up. Half the current travelled through the nearer “arm” of the circuit. The other half travelled through the distant “arm”.
This time, when a bulb was removed, the remaining bulb stayed lit. That’s because the path to the untouched bulb remained intact. The electrons continued to flow along this smaller but complete circuit loop.
