|MadSci Network: Physics|
What is a parallel circuit? The word "circuit" comes from the Latin word for circle. When you run around the kitchen table, you run around a circuit. When you leave home in the morning, go to school and come home again, you have travelled a circuit. A circuit is a path that takes you back to where you started. A parallel circuit is a group of separate paths that start and finish at the same place. If you leave home for school in the morning and your father leaves home for work, but you both return home in the evening, the two of you have travelled a parallel circuit. You can observe a parallel circuit with water, a styrofoam cup, a pencil and a bowl. Fill a styrofoam cup with water. Quickly pour it out. This is an example of static discharge. The water didn't return to the cup. To make a circuit, the water has to return to the cup. You can feel a static discharge of electricity when you scuff your feet on the carpet and touch a doorknob. Poke a small hole on one side of the bottom of the cup with the pencil. Fill the cup with water. Use the bowl to catch the water as it runs out of the cup. You can form a circuit by pouring the water in the bowl back into the cup. When you turn a flashlight on, the switch completes the electrical circuit. When you catch the water with the bowl and pour it back into the cup you are acting like the batteries in the flashlight and powering the circuit. Now, poke another small hole on the other side of the bottom of the cup. Fill the cup with water. Now the water comes out in two SEPARATE streams of water. Catch the water with in bowl and pour it back into the cup. You now have a parallel circuit. The water starts in the cup, takes two paths to the bowl and returns to the cup. When your parents turn on their car headlights, they are completing a parallel circuit. Electricity runs in separate paths from the car battery to each light and back to the battery.
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