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We have a special guest with us here today to teach us some basics about electrical circuits.

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We have Mr. Rick Walker, who is an electrical engineer from NASA Langley Research Center.

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How many people think electricity is mysterious?

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Why do you think electricity is so mysterious?

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It's probably because we can't see it.

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That's a pretty common answer, Jacob.

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Most people have a hard time understanding things they can't see.

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So to help us see how electricity works, we're going to use something that we all know about.

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Let's go outside and learn about the basic components of a circuit using a fire truck and water.

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Whoa!

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Today we're with firefighters from the Fox Hill Company No. 5 in Hampton, Virginia.

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Hey, guys.

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Hi, Rick.

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Let's say these guys were on the scene of a fire.

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What are some things that they would need to be able to put the fire out?

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Water.

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And a fire truck.

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That's right.

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We'll need a fire truck filled with water.

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What else?

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What about a fire hose?

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All right.

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Now how do the firefighters get the water to the fire?

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They hook up the hose to the fire truck.

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Right.

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We definitely have to have the hose hooked up to the truck.

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So what we have here are the basic components of a circuit.

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They have a power source.

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They have conductors or wires and a load.

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What do you mean by a load?

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In a circuit, a load is a device that converts electrical energy into some other form of energy.

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For example, in an electrical circuit, we use a light bulb to convert electricity into light.

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The power source is what supplies our circuit with the energy to do work.

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For example, a battery creates electrical pressure called voltage that will push electrons through the circuit.

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On the fire truck, a pump creates water pressure.

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The pressure will push the water out if there's a path for the water to flow.

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The water travels to the load, which is our water cannon.

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Okay, guys, whenever you're ready.

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All right.

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Whoa!

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Now, let's go inside and compare this to an electrical circuit.

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Who remembers what components we need to make up a simple circuit?

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PJ?

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A power source, conductors, or the wires, and a load.

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That's right.

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What we're going to do is use this battery as our power source, the wires as our conductors, and this lamp will be our load.

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If we connect them in the right order, the circuit will be closed, and the light bulb will light.

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Basically, what we have here is the battery creating an electrical potential called voltage,

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which is pushing the electrons through the wires, up to the light bulb, and back around to the other side of the battery.

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When this circuit's closed, the light bulb lights.

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It's important to remember here that the battery is not creating electricity, but merely pushing electrons around the circuit.

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So what would you call it if you disconnected one of the wires?

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If it's called a closed circuit when the lamp is lit, then would it be called an open circuit when the lamp doesn't light?

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That's right.

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For example, the lights in our room right now, we have a closed circuit.

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But if I was to go over to the wall and flip the switch, what would we have?

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Exactly.

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At home, you use devices like switches and circuit breakers and fuses to make open circuits.