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Hey, you heard me, yeah, you come see our clubhouse and our tree.

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We are kids on a mission to educate ourselves about the NASA vision.

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Come explore math and science cause that's what makes our alliance.

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We are the Wi-Fi Club. We yearn to learn and want to see everything that we can be.

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So come join us on our journey. Don't you touch that dial.

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And welcome to the NASA Wi-Fi House.

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Hey, that's cool. What is it?

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It's this new game I bought. It uses batteries so I can play it at the pool.

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Yes, high score.

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Can I play?

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Sure, here you go.

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So you ready to go to Mr. E's pool?

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Yeah, as soon as Bianca gets up here.

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Whew, it's starting to rain and it's thundering and lightning too.

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Does this mean we can't go swimming?

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I don't know, it doesn't look good.

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Let's see if KSNN is reporting anything on the storm.

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I'm Ted Toon with this Kids Science News Network Bulletin.

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The National Weather Service has issued a severe thunderstorm warning for the immediate listening area.

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Anyone outside should take shelter immediately and no one should go to the pool right now.

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This storm is capable of heavy rain, dangerous lightning and damaging winds.

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We have a report from our on-the-scene reporter, I Am Listening, who is coming to us live from Wattsville.

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Ted, I'm on the western edge of town and I can tell you that the storm is just about here.

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We are experiencing high winds and rain showers.

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From where I'm standing, I can see spectacular lightning.

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That one was close.

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Oh my, the power has gone out.

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Ted, if you can see behind me, the homes of Wattsville have all gone dark.

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Victims of the storm's tremendous electrical surge.

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Back to you.

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Thanks, I Am, for that shocking report.

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We'll be back, so stay tuned to KSNN for the latest news on the storm.

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Unless, of course, your power is out and you can't see or hear me.

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The lights are flickering on and off.

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The storm's right over us.

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Maybe we better get out of the treehouse and into our houses where it's safe.

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Good idea. I'll see you later.

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Our lights are working again.

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I can't wait to go swimming in Mr. E's pool.

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Well, we can't. Mr. E tells me that his power is still out in his house across the street.

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Is that his house right over there?

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Yes.

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Hmm, I wonder what the power is on in our treehouse, but out across the street.

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Well, we are the treehouse detectives.

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We've solved a lot of other problems and we can solve this one.

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What problem? It was just a lightning storm.

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Now, let's not jump to conclusions. We need to think about this scientifically.

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Why do we have to use a scientific method every time?

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Because it works. You know, those scientific methods like observation...

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Hypothesis, variables. Yeah, we got it.

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Well, listen, if it doesn't work this time, then we'll never use it again.

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Like that will ever happen.

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You do know where we need to go to get started, don't you?

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The problem board.

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So what do we know? We know that we had a lightning storm last night.

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And we know the power is on before the storm.

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We also know that the power is still off across the street.

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We need to know if lightning can cause a power outage.

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And we need to know what else can cause power outages.

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And we also need to know why we have power in the treehouse, but not across the street.

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I still think lightning caused the power outage.

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Okay, let's make that our hypothesis. Lightning caused the power outage.

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But that still doesn't explain why we have power in the treehouse and not across the street.

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I'll go do a web search on lightning and see what I can find.

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While you're doing that, let's check our hypothesis.

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How are we going to do that? I don't know. Let's see if Dr. D will help us.

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Hi, Dr. D. Hi.

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Hi, guys.

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Can you tell us what lightning is?

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Sure. Wait a minute, what brings this up?

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Well, I was telling Kaylee and Jacob that the power is still out across the street,

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but it's still on in our treehouse. We're trying to figure out why.

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Where are you going to start?

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We came up with a hypothesis. We think that lightning caused the power outage.

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It was a pretty big storm last night. How are you going to test your hypothesis?

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We're not sure.

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Well, to understand lightning, we first need to look at some basics.

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Let's rip up this paper.

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Now comb your hair briskly and then bring the comb down close to the paper.

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Nice.

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Neat. Why did it do that?

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The ancient Greeks noticed the same thing when they rubbed amber with wool.

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Who's amber?

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Not who, but what. Amber is fossilized tree sap.

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Oh, okay.

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The amber picked up little objects like strands of fiber and hair,

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just like the comb picked up the paper.

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We say that the comb and the amber are electrically charged.

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Can objects do the same thing?

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Sure. This balloon can pick up the paper, too.

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Wow.

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And it picks up other things, too,

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like this rice cereal and salt.

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The balloon will also stick to the wall

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and also attract the stream of water.

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Whoa.

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If you rub the acrylic rod with a plastic bag, it'll do the same thing.

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Now how do you know that the balloon was charged and not the paper?

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Well, if an object is electrically charged,

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it should pick up objects like little pieces of paper or other such objects.

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Let's see.

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Nothing happened.

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Very good. A charged object will pick up other neutral and uncharged objects,

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but an uncharged object won't.

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Let's do an experiment with some tape.

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Bring this bar around.

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Put some tape on the table.

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I'll pull it up real quickly.

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And watch this.

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It attracted the paper.

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It must be charged.

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Now let's try two pieces of tape, one on top of each other.

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Hold on to that, please.

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How can we tell if these are charged?

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We need to do the paper scraps test to find out.

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Let's try it.

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Yep, they're charged all right.

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Well, here's the experiment.

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Let's hang up a single piece of charged tape.

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I will pull up a double tape.

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Rehearse the top piece.

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It attracts the tape, just like before.

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It's repelling the second tape.

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We haven't seen that before.

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What conclusions can you make?

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Well, if an object is charged, it attracts uncharged items,

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but it may attract or repel other charged items.

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Does that mean there are two types of charges?

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That's right. Two types of charges are positive and negative.

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The top piece and the bottom piece have different charges.

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Now let's do this again.

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This time we'll take both pieces of tape in exactly the same way.

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So...

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They must have the same charge.

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That's right.

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Will they attract or repel?

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They repel.

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Let's see. If the charges are different, then they must attract.

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Let's find out.

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All right, we'll use the two tapes again.

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Both have different charges.

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How about that?

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Look at this machine. It's called a Van de Graaff generator.

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Jacob, stand up on this stool, if you would, and put your hands on top.

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I'm going to turn this machine on and transfer a lot of charge into you.

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It won't shock you, I promise.

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Wow, his hair is really standing out.

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Is it because all my hair is charged the same way

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and each strand is repelling or pushing away from the strand next to it?

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That's right. In the beginning, your body was neutral.

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It had the same number of positive and negative charges.

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All the positive charges, protons, and negative charges, electrons.

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When we transfer an awful lot of negatively charged electrons into your body,

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what kind of charge would you have then?

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Well, if the number of electrons and protons in his body were the same,

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then they would basically cancel each other out.

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And then if we added a lot of electrons,

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then I guess his body would be negatively charged.

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That's right.

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And I always thought you were the negative one.

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Now, if we turn the thing on again,

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build up a huge charge on top, move the second ball closer to the first.

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Wow, it looks just like lightning.

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Now, what's going on there?

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Well, the electrons are jumping from the Van de Graaff to the ball.

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It looks more like a flash of light than a bunch of particles.

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Well, I learned that you can't see electrons,

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so how can we see these electrons?

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Well, you're right. Electrons aren't too small to see.

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As the electrons jump from the Van de Graaff to the ball,

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they heat up the air and cause it to glow.

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What you're seeing is the glowing air, not the moving electrons.

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Is this how lightning works?

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Yes, it's very similar.

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So, Dr. D, do we get electricity from lightning?

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Not quite. I'll tell you what.

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I'm going to line you up with a researcher

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from NASA Langley Research Center in Hampton, Virginia.

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His name is Bruce Fisher.

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He's done a lot of studies on lightning.

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I'll arrange for you to meet him at the Virginia Air and Space Center.

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Great. Thanks, Dr. D.

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So, let's get up and go.

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Bye, Dr. D.

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Bye, guys.

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Hi, Mr. Fisher.

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Dr. D said that you have studied lightning

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and could explain it to us.

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Sure. I worked for several years on a research program at NASA Langley

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where we studied the effects of lightning on airplanes.

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What is lightning and how does it work?

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Do you understand about positive and negative charges?

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Yes.

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As a thunderstorm builds and matures,

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the charges tend to separate inside the storm.

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Typically, the positive charges go towards the top of the storm

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and the negative charges go towards the bottom of the storm.

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Now, what's important to remember about positive and negative charges?

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I know that opposite charges attract and like charges repel.

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Exactly.

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What happens as the storm matures,

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you start to get an attraction between the negative charges

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at the bottom of the cloud and the positive charges on the ground.

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And eventually, you'll get those two charges to meet.

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And when they do, there's a channel between them,

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between the positive and the negative.

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That's what we call a lightning bolt,

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and that is a cloud-to-ground lightning discharge.

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Why doesn't the negative and positive charges attract each other in the cloud?

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They can.

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In fact, 70% of all lightning which occurs in nature

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just occurs up in the clouds, what we call cloud-to-cloud lightning.

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Does lightning ever hit the planes?

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Absolutely.

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In fact, let me show you something here in the museum.

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Walk over this way.

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Now, see the airplane over there?

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That's an F-106B Delta Dart, which is a two-seat fighter aircraft,

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and it was used by NASA Langley, where I work,

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for about five or six years to fly through thunderstorms

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to intentionally look for lightning strikes to aircraft.

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The airplane's been struck about 700 times by lightning.

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During that time, I sat in the back seat of the aircraft,

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and I was struck by lightning about 256 times

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during all of our research flights.

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There's no way I go up in a plane during a lightning storm.

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What's it like to fly a plane through a storm?

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The greatest worries that you have when you're flying through a thunderstorm

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is not the lightning, because we were looking for the lightning,

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and the airplane was ready for that.

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What we were frightened of was the turbulence.

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It's a very rough ride inside of thunderstorms.

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This is a very rough-riding aircraft,

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so you get bounced around and jiggled around a lot

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inside the cockpit of the aircraft.

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It's a very rough ride.

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The lightning was the fun part.

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You could see the lightning boom, the lightning flash,

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hit the nose boom of the aircraft.

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You'd see the lightning channel cause sparks

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where it was melting metal on the front of the airplane.

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You'd see the lightning channel flicker.

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Sometimes you'd hear it rumble.

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It was a big enough lightning flash.

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You'd see it sweep from the front of the airplane

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to the back of the airplane, a real light show,

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as if it was in slow motion.

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It only lasts about one second,

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but it seems it takes forever when you see it hit the aircraft.

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And all you would typically hear, because we're wearing headsets,

251
00:13:27,000 --> 00:13:29,000
would be just a snap in your ear,

252
00:13:29,000 --> 00:13:31,000
just a snap when the lightning would strike.

253
00:13:31,000 --> 00:13:33,000
But a lot of the lightning flashes, lightning strikes,

254
00:13:33,000 --> 00:13:35,000
we never saw because they all hit back up

255
00:13:35,000 --> 00:13:37,000
in the rear end of the airplane,

256
00:13:37,000 --> 00:13:40,000
from wingtip to wingtip around the exhaust of the engine.

257
00:13:40,000 --> 00:13:42,000
So we'd have to come back afterwards

258
00:13:42,000 --> 00:13:44,000
and look at videotapes with the pilots

259
00:13:44,000 --> 00:13:46,000
and figure out where the lightning strikes hit us

260
00:13:46,000 --> 00:13:48,000
and when the lightning strikes hit us.

261
00:13:48,000 --> 00:13:51,000
Because most of them, we never knew we'd been hit.

262
00:13:51,000 --> 00:13:53,000
You might just hear a snap, and you might lose that snap

263
00:13:53,000 --> 00:13:55,000
and all the other noises that are going on

264
00:13:55,000 --> 00:13:57,000
inside the cockpit of the airplane.

265
00:13:57,000 --> 00:14:00,000
All the research that we did is being used

266
00:14:00,000 --> 00:14:02,000
to make commercial aircraft safer,

267
00:14:02,000 --> 00:14:04,000
to make fighter aircraft safer,

268
00:14:04,000 --> 00:14:08,000
and it's even being used to make the launches of the space shuttle safer

269
00:14:08,000 --> 00:14:10,000
so that they don't get involved with lightning

270
00:14:10,000 --> 00:14:13,000
when they're trying to go into orbit from the Kennedy Space Center.

271
00:14:13,000 --> 00:14:16,000
Wow! Does electricity come from lightning?

272
00:14:16,000 --> 00:14:18,000
Lightning is an electrical spark,

273
00:14:18,000 --> 00:14:22,000
but power and electricity and lightning are not quite the same thing.

274
00:14:22,000 --> 00:14:24,000
Can lightning cause the power to go out?

275
00:14:24,000 --> 00:14:27,000
Lightning can cause all sorts of unpleasant things to happen,

276
00:14:27,000 --> 00:14:29,000
including power outages.

277
00:14:29,000 --> 00:14:31,000
But I'm not an expert in power generation.

278
00:14:31,000 --> 00:14:33,000
I'm an aerospace engineer.

279
00:14:33,000 --> 00:14:35,000
What you should do is send an e-mail to your local power company

280
00:14:35,000 --> 00:14:37,000
and see what they can tell you about power outages

281
00:14:37,000 --> 00:14:39,000
and power disturbances from lightning.

282
00:14:39,000 --> 00:14:41,000
Okay. Thanks for your help, Mr. Fisher.

283
00:14:41,000 --> 00:14:42,000
You're welcome.

284
00:14:42,000 --> 00:14:43,000
Bye.

285
00:14:43,000 --> 00:14:44,000
Have a good day.

286
00:14:48,000 --> 00:14:51,000
I'm rubbing this balloon on my arm to give it charge.

287
00:14:51,000 --> 00:14:53,000
Okay, that ought to be enough.

288
00:14:53,000 --> 00:14:55,000
Now let's see if we can move this can.

289
00:14:55,000 --> 00:14:57,000
Wow! Pretty neat.

290
00:14:57,000 --> 00:14:59,000
You can see how to do this experiment

291
00:14:59,000 --> 00:15:02,000
and other experiments on static electricity

292
00:15:02,000 --> 00:15:08,000
at the NASA WIFOS website at wifos.larc.nasa.gov.

293
00:15:09,000 --> 00:15:12,000
Now that we've learned about static electricity and lightning,

294
00:15:12,000 --> 00:15:14,000
let's go back to our problem board.

295
00:15:14,000 --> 00:15:15,000
What do we know?

296
00:15:15,000 --> 00:15:19,000
We know that lightning isn't the same as the electricity we use in our homes.

297
00:15:19,000 --> 00:15:22,000
We've learned about positive and negative charges

298
00:15:22,000 --> 00:15:25,000
and how opposite charges attract and like charges repel.

299
00:15:25,000 --> 00:15:27,000
What else do we know?

300
00:15:27,000 --> 00:15:29,000
Remember the e-mail that I sent to the power company?

301
00:15:29,000 --> 00:15:32,000
Well, the response says that lightning can cause an outage

302
00:15:32,000 --> 00:15:36,000
either at the power source or somewhere between the power source and our home.

303
00:15:36,000 --> 00:15:37,000
Hmm.

304
00:15:37,000 --> 00:15:41,000
So maybe we should change our hypothesis to lightning hit the power source.

305
00:15:41,000 --> 00:15:43,000
But what is a power source?

306
00:15:43,000 --> 00:15:45,000
Isn't it the place where they make the power?

307
00:15:45,000 --> 00:15:47,000
You know, where the power comes from?

308
00:15:47,000 --> 00:15:49,000
Like a bunch of big batteries?

309
00:15:49,000 --> 00:15:55,000
I suppose we need to know what a power source is and how power gets to our homes.

310
00:15:55,000 --> 00:15:58,000
I guess that's the next part of our investigation.

311
00:15:59,000 --> 00:16:01,000
So how's your research coming along?

312
00:16:01,000 --> 00:16:03,000
Fine. We changed our hypothesis.

313
00:16:03,000 --> 00:16:05,000
You have to revise your hypothesis sometimes.

314
00:16:05,000 --> 00:16:07,000
It's part of the scientific process.

315
00:16:07,000 --> 00:16:08,000
How does it read now?

316
00:16:08,000 --> 00:16:10,000
We said that lightning hit the power source.

317
00:16:10,000 --> 00:16:11,000
I see.

318
00:16:11,000 --> 00:16:12,000
Your train set is really neat.

319
00:16:12,000 --> 00:16:13,000
Well, thank you.

320
00:16:13,000 --> 00:16:14,000
We're working on it a long time.

321
00:16:14,000 --> 00:16:16,000
Just putting the finishing touches on it.

322
00:16:16,000 --> 00:16:17,000
Can you turn it on, Dr. D?

323
00:16:17,000 --> 00:16:18,000
Sure.

324
00:16:19,000 --> 00:16:21,000
That's funny. It was working before.

325
00:16:21,000 --> 00:16:23,000
Well, is the train plugged in?

326
00:16:23,000 --> 00:16:24,000
Let me check.

327
00:16:24,000 --> 00:16:26,000
Yeah, it's still plugged in.

328
00:16:26,000 --> 00:16:27,000
I'm really stumped.

329
00:16:29,000 --> 00:16:30,000
So what's up?

330
00:16:30,000 --> 00:16:33,000
Can you think of some reasons why Dr. D's train set doesn't work?

331
00:16:33,000 --> 00:16:37,000
Why is the power out on one side of the street and not the other?

332
00:16:37,000 --> 00:16:40,000
Do you think that lightning caused the power outage?

333
00:16:40,000 --> 00:16:44,000
How can the Treehouse Detectives use scientific methods to solve the problem?

334
00:16:44,000 --> 00:16:47,000
Stay tuned. We'll have more next time.

335
00:16:49,000 --> 00:16:50,000
Check it out.

336
00:16:54,000 --> 00:16:58,000
So, Dr. D, PJ tells us that your train set's pretty cool

337
00:16:58,000 --> 00:17:00,000
and that you're having problems with it.

338
00:17:00,000 --> 00:17:01,000
Have you figured out what was wrong yet?

339
00:17:01,000 --> 00:17:04,000
Not yet, but I'll bet if we work together as a group

340
00:17:04,000 --> 00:17:07,000
and check out the variables one at a time, we'll find the problem.

341
00:17:07,000 --> 00:17:08,000
Okay.

342
00:17:08,000 --> 00:17:09,000
What's a variable?

343
00:17:09,000 --> 00:17:14,000
A variable is one specific thing that can affect or change the end result or the answer.

344
00:17:14,000 --> 00:17:15,000
I've got an idea.

345
00:17:15,000 --> 00:17:17,000
I bet it's the wall outlet.

346
00:17:17,000 --> 00:17:20,000
There's no electricity there. Nothing else will work.

347
00:17:20,000 --> 00:17:22,000
Let's make that our first variable.

348
00:17:22,000 --> 00:17:24,000
How can we check out the wall outlet?

349
00:17:24,000 --> 00:17:26,000
We can plug in something that we know works.

350
00:17:26,000 --> 00:17:27,000
Exactly right.

351
00:17:27,000 --> 00:17:29,000
I've got a plasma ball we can use.

352
00:17:29,000 --> 00:17:32,000
Let's turn the lights down a little so we can see it better

353
00:17:32,000 --> 00:17:34,000
and we'll plug it in over there to make sure that it's working.

354
00:17:37,000 --> 00:17:38,000
Cool!

355
00:17:38,000 --> 00:17:41,000
Now let's plug it into the same outlet the train set up uses.

356
00:17:43,000 --> 00:17:44,000
It works fine.

357
00:17:44,000 --> 00:17:46,000
I guess we've eliminated one possible variable.

358
00:17:47,000 --> 00:17:49,000
I'll check out a couple of other things later.

359
00:17:49,000 --> 00:17:52,000
By the way, how are you coming along with your electricity mystery?

360
00:17:52,000 --> 00:17:57,000
Well, we still think lightning caused the power outage across the street from the treehouse.

361
00:17:57,000 --> 00:17:59,000
We know that lightning doesn't cause electricity,

362
00:17:59,000 --> 00:18:02,000
but we're still not sure where it comes from.

363
00:18:02,000 --> 00:18:04,000
Can you tell us?

364
00:18:04,000 --> 00:18:07,000
Well, electricity is electric charges flowing through the wires of a circuit.

365
00:18:07,000 --> 00:18:10,000
In a standard circuit, the charges are electrons.

366
00:18:10,000 --> 00:18:12,000
There are several ways to force the charges to flow.

367
00:18:12,000 --> 00:18:14,000
Do you know what some of them are?

368
00:18:14,000 --> 00:18:16,000
Don't batteries produce electricity?

369
00:18:16,000 --> 00:18:17,000
That's right.

370
00:18:17,000 --> 00:18:21,000
In fact, we can make our own battery out of lemons or other pieces of fruit.

371
00:18:21,000 --> 00:18:24,000
A battery? From fruit?

372
00:18:24,000 --> 00:18:25,000
Sure.

373
00:18:25,000 --> 00:18:28,000
A flashlight or the battery in your parents' car isn't made of lemons,

374
00:18:28,000 --> 00:18:30,000
but it works using the same principles.

375
00:18:30,000 --> 00:18:32,000
Can you use a lemon to power something?

376
00:18:32,000 --> 00:18:33,000
Let's see.

377
00:18:33,000 --> 00:18:35,000
I've got a little LCD clock.

378
00:18:35,000 --> 00:18:38,000
It normally works with a watch battery, about one and a half volts.

379
00:18:38,000 --> 00:18:42,000
Hook together some lemons like this and let's see what happens.

380
00:18:43,000 --> 00:18:44,000
It's working.

381
00:18:44,000 --> 00:18:46,000
That's amazing.

382
00:18:46,000 --> 00:18:48,000
Can you think of another way to create electricity?

383
00:18:48,000 --> 00:18:49,000
How about solar power?

384
00:18:49,000 --> 00:18:51,000
That's called a solar cell, isn't it?

385
00:18:51,000 --> 00:18:54,000
I saw on TV that NASA uses solar cells to power satellites

386
00:18:54,000 --> 00:18:56,000
and even the International Space Station.

387
00:18:56,000 --> 00:18:57,000
That's right.

388
00:18:57,000 --> 00:18:59,000
Look at this solar-powered bicyclist here.

389
00:18:59,000 --> 00:19:03,000
The brighter the light, the faster he pedals.

390
00:19:06,000 --> 00:19:11,000
So do you know how solar cells and batteries cause the charges to flow?

391
00:19:11,000 --> 00:19:12,000
What do you mean?

392
00:19:12,000 --> 00:19:14,000
Electricity doesn't appear out of nowhere.

393
00:19:14,000 --> 00:19:18,000
A very important law of physics says you can't get something for nothing.

394
00:19:18,000 --> 00:19:21,000
It takes work to push the charges through the wires,

395
00:19:21,000 --> 00:19:24,000
and the energy to do that work must come from someplace.

396
00:19:24,000 --> 00:19:27,000
With a solar cell, it uses the energy of the sun,

397
00:19:27,000 --> 00:19:29,000
and batteries use chemical energy.

398
00:19:29,000 --> 00:19:31,000
What other kinds of sources of electricity are there?

399
00:19:31,000 --> 00:19:33,000
A power company is the source of electricity.

400
00:19:33,000 --> 00:19:36,000
It's easy to plug into our outlets and get power.

401
00:19:36,000 --> 00:19:38,000
But I guess I don't know how they produce it.

402
00:19:38,000 --> 00:19:40,000
Do they use a battery?

403
00:19:40,000 --> 00:19:41,000
No, that's a good guess.

404
00:19:41,000 --> 00:19:45,000
The power company uses mechanical motion, however, to create electricity.

405
00:19:45,000 --> 00:19:46,000
Let me illustrate.

406
00:19:46,000 --> 00:19:49,000
Turn this crank, and tell me what happens.

407
00:19:57,000 --> 00:20:00,000
The faster I turn the handle, the brighter the light bulb glows.

408
00:20:00,000 --> 00:20:01,000
That's right.

409
00:20:01,000 --> 00:20:02,000
When you turn the handle,

410
00:20:02,000 --> 00:20:06,000
you're providing the energy to force the electrons to move through the wire.

411
00:20:06,000 --> 00:20:09,000
The motion that charges through the wire is called a current.

412
00:20:09,000 --> 00:20:11,000
This time, turn the crank, keep your eyes closed,

413
00:20:11,000 --> 00:20:13,000
and tell me when something happens.

414
00:20:17,000 --> 00:20:19,000
Wow, it's a lot easier to turn now.

415
00:20:19,000 --> 00:20:20,000
What happened?

416
00:20:20,000 --> 00:20:22,000
I screwed the light bulb.

417
00:20:22,000 --> 00:20:25,000
It only takes work to turn the crank as long as you're lighting the bulb.

418
00:20:25,000 --> 00:20:27,000
You're only lighting one bulb.

419
00:20:27,000 --> 00:20:30,000
Let's add some more bulbs, see if it's harder to turn the crank.

420
00:20:33,000 --> 00:20:35,000
All right, go ahead.

421
00:20:35,000 --> 00:20:37,000
Whoa, it's a lot harder now.

422
00:20:37,000 --> 00:20:39,000
I'm trying to work at this.

423
00:20:40,000 --> 00:20:44,000
But Dr. D, obviously people don't turn the cranks on a power plant.

424
00:20:44,000 --> 00:20:48,000
What other sources of energy could you use other than people power to turn the crank?

425
00:20:48,000 --> 00:20:50,000
We can use wind power to turn the crank.

426
00:20:50,000 --> 00:20:52,000
Well, wind power is used to create electricity,

427
00:20:52,000 --> 00:20:55,000
but it's not often used for large-scale power production.

428
00:20:55,000 --> 00:20:58,000
I think the power plant in our town uses natural gas.

429
00:20:58,000 --> 00:20:59,000
That's right.

430
00:20:59,000 --> 00:21:03,000
Power plants use coal, oil, natural gas, and even nuclear fission

431
00:21:03,000 --> 00:21:05,000
to provide the energy to create electricity.

432
00:21:05,000 --> 00:21:09,000
In each of these cases, the burning of coal, oil, natural gas,

433
00:21:09,000 --> 00:21:12,000
and the fission of uranium provides the heat to produce steam.

434
00:21:12,000 --> 00:21:14,000
The steam causes the turbine to spin,

435
00:21:14,000 --> 00:21:18,000
which turns the crank and the generator, producing the electricity.

436
00:21:18,000 --> 00:21:20,000
It's just like our experiment, but with more power.

437
00:21:20,000 --> 00:21:25,000
There's another natural process that can be used to provide the energy to create electricity.

438
00:21:25,000 --> 00:21:26,000
Do you know what it is?

439
00:21:26,000 --> 00:21:28,000
Hmm, isn't it flowing water?

440
00:21:28,000 --> 00:21:29,000
That's right.

441
00:21:29,000 --> 00:21:32,000
When water flows downhill, it has the energy to turn the turbine.

442
00:21:32,000 --> 00:21:36,000
One of the most interesting power projects in the United States is at Niagara Falls.

443
00:21:36,000 --> 00:21:37,000
Why don't you check it out?

444
00:21:37,000 --> 00:21:41,000
Okay, I'll e-mail them and see if we can talk to them about their facility.

445
00:21:46,000 --> 00:21:48,000
Hi, I'm Joanne Wilmot,

446
00:21:48,000 --> 00:21:53,000
the New York Power Authority's Regional Manager for Community Relations here in western New York.

447
00:21:53,000 --> 00:21:59,000
We got your e-mail and understand you'd like to learn more about the Niagara Power Project and how it works.

448
00:21:59,000 --> 00:22:01,000
Well, let me show you around.

449
00:22:01,000 --> 00:22:05,000
Before we get started, do you know anything about the Niagara Power Project?

450
00:22:05,000 --> 00:22:09,000
I know that it sits on the Niagara River between New York and Ontario.

451
00:22:09,000 --> 00:22:10,000
That's right.

452
00:22:10,000 --> 00:22:16,000
The Niagara Power Project is the result of cooperation between the United States and Canada.

453
00:22:16,000 --> 00:22:23,000
As a matter of fact, the Canadian power plants are located directly across the river from ours.

454
00:22:23,000 --> 00:22:29,000
Both the United States and Canada have shared the waters of the Niagara River for many years,

455
00:22:29,000 --> 00:22:34,000
and both countries are firmly committed to preserving the beauty of Niagara Falls.

456
00:22:34,000 --> 00:22:37,000
Niagara Falls is really beautiful.

457
00:22:37,000 --> 00:22:39,000
I visited once on summer vacation.

458
00:22:39,000 --> 00:22:40,000
It sure is.

459
00:22:40,000 --> 00:22:46,000
And did you know that when the Niagara Project produced its first power back in 1961,

460
00:22:46,000 --> 00:22:51,000
it was the largest hydroelectric power plant in the western world at that time?

461
00:22:51,000 --> 00:22:56,000
Today, it's still New York State's largest electricity generator.

462
00:22:56,000 --> 00:23:03,000
And here we have the capability to generate 2,400,000 kilowatts of electricity.

463
00:23:03,000 --> 00:23:09,000
That's enough to light 24,100 watt light bulbs at any one time.

464
00:23:09,000 --> 00:23:17,000
The low-cost power generated here also saves New York State's businesses and residents millions of dollars annually.

465
00:23:17,000 --> 00:23:19,000
How is the electricity made?

466
00:23:19,000 --> 00:23:21,000
Here's how it works.

467
00:23:21,000 --> 00:23:27,000
The Niagara Power Project, located about four and a half miles downstream from Niagara Falls,

468
00:23:27,000 --> 00:23:34,000
consists of two main facilities, the Robert Moses Niagara Power Plant with 13 generating units

469
00:23:34,000 --> 00:23:40,000
and the Lewiston Pump Generating Plant with 12 pump turbine generating units.

470
00:23:40,000 --> 00:23:45,000
Between the two plants is a large forebay or open canal.

471
00:23:45,000 --> 00:23:49,000
It's almost one mile long and about 500 feet wide.

472
00:23:49,000 --> 00:23:56,000
Behind the Lewiston plant is a 1,900-acre reservoir, which is like a large bathtub,

473
00:23:56,000 --> 00:24:03,000
and that holds additional supplies of liquid fuel, about 20 billion gallons worth.

474
00:24:03,000 --> 00:24:10,000
Basically, water is diverted from the Niagara River up to 600,000 gallons a second

475
00:24:10,000 --> 00:24:16,000
and travels through two underground conduits or tunnels under the city of Niagara Falls

476
00:24:16,000 --> 00:24:20,000
and the surrounding towns to the project's forebay.

477
00:24:20,000 --> 00:24:27,000
From there, water flowing through the Robert Moses plant spins the turbines that power the generators,

478
00:24:27,000 --> 00:24:32,000
converting mechanical energy into electrical energy.

479
00:24:32,000 --> 00:24:38,000
At night, when electricity demand is low, the Lewiston units operate as pumps,

480
00:24:38,000 --> 00:24:43,000
carrying water from the forebay up to the plant's reservoir.

481
00:24:43,000 --> 00:24:50,000
Then, during the day, when electricity use increases, the Lewiston pumps reverse direction

482
00:24:50,000 --> 00:24:55,000
and become turbine generators, similar to those at the Robert Moses plant.

483
00:24:55,000 --> 00:25:02,000
The water then flows back into the forebay and is used again at the Robert Moses plant.

484
00:25:02,000 --> 00:25:10,000
Using the water twice to produce electricity allows us to increase our efficiency and production.

485
00:25:10,000 --> 00:25:16,000
You learned earlier that there are numerous ways to produce electricity using different fuels.

486
00:25:16,000 --> 00:25:20,000
Well, here at a hydroelectric project, we use water as our fuel.

487
00:25:20,000 --> 00:25:27,000
So hydroelectric power is one of the cleanest and environmentally friendly ways to produce electricity.

488
00:25:27,000 --> 00:25:30,000
Is all the water in the river used to make power?

489
00:25:30,000 --> 00:25:33,000
That's a very good question, and the answer is no.

490
00:25:33,000 --> 00:25:37,000
If all the water in the Niagara River was used for power production,

491
00:25:37,000 --> 00:25:40,000
there wouldn't be any going over Niagara Falls.

492
00:25:40,000 --> 00:25:43,000
And because the falls is such an international attraction,

493
00:25:43,000 --> 00:25:47,000
the United States and Canada signed a treaty in 1950,

494
00:25:47,000 --> 00:25:54,000
and that treaty regulates the amount of water that must flow over Niagara Falls at all times of the year.

495
00:25:54,000 --> 00:25:57,000
The treaty says that during the tourist season,

496
00:25:57,000 --> 00:26:02,000
100,000 cubic feet per second must flow over Niagara Falls.

497
00:26:02,000 --> 00:26:06,000
A cubic foot is equal to about 7.5 gallons.

498
00:26:06,000 --> 00:26:11,000
So if we multiply that by 100,000 cubic feet per second,

499
00:26:11,000 --> 00:26:19,000
there is approximately 750,000 gallons of water per second flowing over Niagara Falls during the tourist season.

500
00:26:19,000 --> 00:26:22,000
So after the power is made, where does it go?

501
00:26:22,000 --> 00:26:27,000
The power generated here at the Niagara project goes to a variety of customers.

502
00:26:27,000 --> 00:26:32,000
Much of it stays right here in western New York for business and industry to use.

503
00:26:32,000 --> 00:26:39,000
Some also goes to residential customers, both here in western New York as well as throughout New York State.

504
00:26:39,000 --> 00:26:45,000
And a small percentage of the power generated here at Niagara is sold to neighboring states.

505
00:26:45,000 --> 00:26:48,000
Can you tell us what can cause a power outage?

506
00:26:48,000 --> 00:26:52,000
Power outages can be caused by a number of factors.

507
00:26:52,000 --> 00:26:55,000
Some can simply be equipment failures.

508
00:26:55,000 --> 00:27:01,000
Other times, severe storms, either wind storms or in the northern climates, ice storms,

509
00:27:01,000 --> 00:27:06,000
can cause damage to power lines and thereby cause a power outage.

510
00:27:06,000 --> 00:27:13,000
Sometimes it's just our customers requiring and using more electricity than the power plant can generate.

511
00:27:13,000 --> 00:27:18,000
That will overload the system and sometimes also cause a power outage.

512
00:27:18,000 --> 00:27:20,000
Thanks for telling us about Niagara Falls.

513
00:27:20,000 --> 00:27:24,000
Thanks so much for stopping by and we'll see you later.

514
00:27:24,000 --> 00:27:29,000
So you can either set this radio out in the sun or turn this crank on the side and it plays for hours.

515
00:27:29,000 --> 00:27:31,000
Pretty neat. How does it do that?

516
00:27:31,000 --> 00:27:36,000
Well, the solar power or the hand crank charges up the rechargeable battery that's inside of a radio.

517
00:27:36,000 --> 00:27:39,000
Did you have it the other night when the power went out?

518
00:27:39,000 --> 00:27:43,000
Yeah, it was really handy. I could listen to KSNN even though the electricity was out.

519
00:27:43,000 --> 00:27:46,000
The people across the street could use it right now.

520
00:27:46,000 --> 00:27:49,000
What's that sound? Is it your radio?

521
00:27:49,000 --> 00:27:51,000
No, I think it's KSNN.

522
00:27:51,000 --> 00:27:52,000
KSNN!

523
00:27:57,000 --> 00:27:59,000
I'm Ted Toon and this is KSNN.

524
00:27:59,000 --> 00:28:03,000
Last night's storm knocked out power for thousands of customers in Wattsville.

525
00:28:03,000 --> 00:28:08,000
Just moments ago, the power company reports that service has been restored to most of the area.

526
00:28:08,000 --> 00:28:11,000
I Am Listening is standing by. I Am?

527
00:28:11,000 --> 00:28:15,000
Ted, I'm in Wattsville with Mr. Eel Ektrik.

528
00:28:15,000 --> 00:28:20,000
Now, Mr. Ektrik, you still do not have power. Is that right?

529
00:28:20,000 --> 00:28:23,000
Uh, that is correct.

530
00:28:23,000 --> 00:28:31,000
Does having no power make it harder for you and Ektrik Eel to stun and then eat your prey?

531
00:28:31,000 --> 00:28:36,000
Uh, no. You see, it's my house that's without power.

532
00:28:36,000 --> 00:28:42,000
I, on the other hand, am fully capable of delivering up to 600 volts.

533
00:28:42,000 --> 00:28:44,000
Just like that.

534
00:28:45,000 --> 00:28:50,000
B-b-b-b-b-b-b-b-b-b-back to you, T-t-t-t-t-t-t-Ted.

535
00:28:50,000 --> 00:28:54,000
That was I Am Listening with another supercharged report.

536
00:28:54,000 --> 00:29:00,000
In other news, a proposed major highway expansion through the Charles Schultz National Forest was vetoed by the president.

537
00:29:00,000 --> 00:29:04,000
Let's get back to work and figure out why there's still no power across the street.

538
00:29:04,000 --> 00:29:05,000
What do we know?

539
00:29:05,000 --> 00:29:08,000
We know that there's no lightning damage at the power source.

540
00:29:08,000 --> 00:29:13,000
Because if there was a problem at the power plant, the whole area would be without electricity.

541
00:29:13,000 --> 00:29:17,000
We also know that there's no equipment damage and that power has been restored across the area.

542
00:29:17,000 --> 00:29:18,000
What do we need to know?

543
00:29:18,000 --> 00:29:22,000
We need to know why the power is out only across the street.

544
00:29:22,000 --> 00:29:26,000
When we talked to Niagara Falls, they told us about how power travels in a circuit.

545
00:29:26,000 --> 00:29:29,000
So I think we need to know what a circuit is and how a circuit works.

546
00:29:29,000 --> 00:29:31,000
Okay, so where do we go?

547
00:29:31,000 --> 00:29:34,000
Uh, let's go to houses across the street.

548
00:29:34,000 --> 00:29:36,000
Yes, where the power is out.

549
00:29:36,000 --> 00:29:42,000
Alright, I'll change our hypothesis to say that the problem is somewhere between the power source and the houses across the street.

550
00:29:42,000 --> 00:29:44,000
I'll type these notes into the computer.

551
00:29:44,000 --> 00:29:46,000
I think we're on the right track.

552
00:29:46,000 --> 00:29:49,000
We must be getting closer.

553
00:29:49,000 --> 00:29:53,000
So, Dr. D, have you figured out what's wrong with the train yet?

554
00:29:53,000 --> 00:29:54,000
No, I worked on it some more.

555
00:29:54,000 --> 00:29:57,000
I checked the electrical connections to make sure they were tight.

556
00:29:57,000 --> 00:30:00,000
The train is still not getting any electricity.

557
00:30:00,000 --> 00:30:01,000
What are you going to do now?

558
00:30:01,000 --> 00:30:04,000
Well, I have some electrical test equipment on my workbench.

559
00:30:04,000 --> 00:30:08,000
I think I'll unplug the power unit, take it to my workbench tonight and check it out.

560
00:30:08,000 --> 00:30:10,000
Hopefully, this will bring us some conclusions.

561
00:30:10,000 --> 00:30:12,000
Good luck.

562
00:30:12,000 --> 00:30:13,000
So what's up?

563
00:30:13,000 --> 00:30:18,000
How will learning about the power plant help the treehouse detectives solve their case?

564
00:30:18,000 --> 00:30:21,000
Are they right to revise their hypothesis?

565
00:30:21,000 --> 00:30:24,000
What do you think is wrong with Dr. D's train?

566
00:30:24,000 --> 00:30:29,000
We'll have more on the next segment of The Case of the Electricity Mystery.

567
00:30:32,000 --> 00:30:36,000
I did a web search on electricity and found some really interesting facts.

568
00:30:36,000 --> 00:30:37,000
Like what?

569
00:30:37,000 --> 00:30:39,000
Well, you know about Tesla or Alexandra Volta?

570
00:30:39,000 --> 00:30:40,000
I think I've heard of them.

571
00:30:40,000 --> 00:30:43,000
I found a video clip about the history of electricity on the internet.

572
00:30:43,000 --> 00:30:46,000
Let's watch it. Maybe we'll find some interesting facts.

573
00:30:53,000 --> 00:30:57,000
And now, the history of electricity.

574
00:30:57,000 --> 00:30:59,000
Here's Dr. Textbook.

575
00:31:00,000 --> 00:31:02,000
Hello.

576
00:31:02,000 --> 00:31:06,000
Maybe you think that one or two people discovered electricity.

577
00:31:06,000 --> 00:31:08,000
Well, actually, electricity is all around us.

578
00:31:08,000 --> 00:31:10,000
It occurs in nature.

579
00:31:12,000 --> 00:31:14,000
Very funny.

580
00:31:14,000 --> 00:31:16,000
An electric buzzer.

581
00:31:16,000 --> 00:31:20,000
Now, you've probably heard some story about Ben Franklin flying his kite.

582
00:31:20,000 --> 00:31:25,000
Well, don't believe for one second that Mr. Franklin was standing out in a wet field with lightning raging about him,

583
00:31:25,000 --> 00:31:27,000
holding onto a brass key.

584
00:31:27,000 --> 00:31:32,000
No, he actually was standing in the distance, observing the kite, taking notes,

585
00:31:32,000 --> 00:31:37,000
and what he found out was that lightning is actually an electrical spark.

586
00:31:37,000 --> 00:31:40,000
Now, on to Alexandra Volta.

587
00:31:40,000 --> 00:31:43,000
Mr. Volta was the first man to build a battery,

588
00:31:43,000 --> 00:31:46,000
and he did this by taking small plates of copper and zinc

589
00:31:46,000 --> 00:31:49,000
and putting moist pieces of paper in between it.

590
00:31:49,000 --> 00:31:55,000
So, as an ode to Volta, I will take this nine-volt battery and stick it on my moist tongue.

591
00:31:57,000 --> 00:31:59,000
Not a very good idea.

592
00:32:00,000 --> 00:32:06,000
Well, Thomas Edison built a generator to make electrical current,

593
00:32:06,000 --> 00:32:08,000
but it actually was a man called Nikola Tesla

594
00:32:08,000 --> 00:32:13,000
who found out that by alternating the electrons in an electrical circuit

595
00:32:13,000 --> 00:32:15,000
was a better way to produce electricity,

596
00:32:15,000 --> 00:32:17,000
and this we call alternating current.

597
00:32:17,000 --> 00:32:20,000
And the first place this occurred was in Niagara Falls.

598
00:32:22,000 --> 00:32:25,000
Wait! There's more to learn!

599
00:32:25,000 --> 00:32:28,000
This has been The History of Electricity.

600
00:32:29,000 --> 00:32:32,000
You know, studying electricity is really interesting.

601
00:32:32,000 --> 00:32:34,000
I think if we're going to solve this problem,

602
00:32:34,000 --> 00:32:38,000
we need to learn more about electricity and how it comes into our homes.

603
00:32:38,000 --> 00:32:40,000
Hmm, I wonder how a circuit works.

604
00:32:40,000 --> 00:32:43,000
Maybe we'll get a better understanding from tomorrow's classroom lesson.

605
00:32:44,000 --> 00:32:49,000
We have a special guest with us here today to teach us some basics about electrical circuits.

606
00:32:49,000 --> 00:32:54,000
We have Mr. Rick Walker, who is an electrical engineer from NASA Langley Research Center.

607
00:32:54,000 --> 00:32:57,000
How many people think electricity is mysterious?

608
00:32:59,000 --> 00:33:01,000
Why do you think electricity is so mysterious?

609
00:33:01,000 --> 00:33:03,000
It's probably because we can't see it.

610
00:33:03,000 --> 00:33:05,000
That's a pretty common answer, Jacob.

611
00:33:05,000 --> 00:33:08,000
Most people have a hard time understanding things they can't see.

612
00:33:08,000 --> 00:33:10,000
So to help us see how electricity works,

613
00:33:10,000 --> 00:33:13,000
we're going to use something that we all know about.

614
00:33:13,000 --> 00:33:16,000
Let's go outside and learn about the basic components of a circuit

615
00:33:16,000 --> 00:33:18,000
using a fire truck and water.

616
00:33:20,000 --> 00:33:24,000
Today we're with firefighters from the Fox Hill Company No. 5 in Hampton, Virginia.

617
00:33:24,000 --> 00:33:25,000
Hey, guys.

618
00:33:25,000 --> 00:33:26,000
Hi, Rick.

619
00:33:26,000 --> 00:33:28,000
Let's say these guys were on the scene of a fire.

620
00:33:28,000 --> 00:33:31,000
What are some things that they would need to be able to put the fire out?

621
00:33:31,000 --> 00:33:32,000
Water.

622
00:33:32,000 --> 00:33:33,000
And a fire truck.

623
00:33:33,000 --> 00:33:34,000
That's right.

624
00:33:34,000 --> 00:33:35,000
We'll need a fire truck filled with water.

625
00:33:35,000 --> 00:33:36,000
What else?

626
00:33:36,000 --> 00:33:37,000
What about a fire hose?

627
00:33:37,000 --> 00:33:38,000
All right.

628
00:33:38,000 --> 00:33:40,000
Now how do the firefighters get the water to the fire?

629
00:33:40,000 --> 00:33:42,000
They hook up the hose to the fire truck.

630
00:33:42,000 --> 00:33:43,000
Right.

631
00:33:43,000 --> 00:33:45,000
We definitely have to have the hose hooked up to the truck.

632
00:33:45,000 --> 00:33:48,000
So what we have here are the basic components of a circuit.

633
00:33:48,000 --> 00:33:50,000
They have a power source.

634
00:33:50,000 --> 00:33:53,000
They have conductors or wires and a load.

635
00:33:53,000 --> 00:33:55,000
What do you mean by a load?

636
00:33:55,000 --> 00:33:59,000
In a circuit, a load is a device that converts electrical energy into some other form of energy.

637
00:33:59,000 --> 00:34:04,000
For example, in an electrical circuit, we use a light bulb to convert electricity into light.

638
00:34:04,000 --> 00:34:08,000
The power source is what supplies our circuit with the energy to do work.

639
00:34:08,000 --> 00:34:13,000
For example, a battery creates electrical pressure called voltage that will push electrons through the circuit.

640
00:34:13,000 --> 00:34:16,000
On the fire truck, a pump creates water pressure.

641
00:34:16,000 --> 00:34:20,000
The pressure will push the water out if there's a path for the water to flow.

642
00:34:21,000 --> 00:34:24,000
The water travels to the load, which is our water cannon.

643
00:34:24,000 --> 00:34:26,000
Okay, guys, whenever you're ready.

644
00:34:44,000 --> 00:34:47,000
Now let's go inside and compare this to an electrical circuit.

645
00:34:51,000 --> 00:34:53,000
Who remembers what components we need to make up a simple circuit?

646
00:34:55,000 --> 00:34:56,000
PJ?

647
00:34:56,000 --> 00:34:59,000
A power source, conductors, or the wires, and a load.

648
00:34:59,000 --> 00:35:00,000
That's right.

649
00:35:00,000 --> 00:35:06,000
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.

650
00:35:06,000 --> 00:35:11,000
If we connect them in the right order, the circuit will be closed and the light bulb will light.

651
00:35:12,000 --> 00:35:16,000
Basically, what we have here is the battery creating an electrical potential called voltage,

652
00:35:16,000 --> 00:35:21,000
which is pushing the electrons through the wires, up to the light bulb, and back around to the other side of the battery.

653
00:35:22,000 --> 00:35:24,000
When this circuit's closed, the light bulb lights.

654
00:35:24,000 --> 00:35:30,000
It's important to remember here that the battery is not creating electricity, but merely pushing electrons around the circuit.

655
00:35:31,000 --> 00:35:34,000
So what would you call it if you disconnected one of the wires?

656
00:35:34,000 --> 00:35:39,000
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?

657
00:35:39,000 --> 00:35:40,000
That's right.

658
00:35:40,000 --> 00:35:43,000
For example, the lights in our room right now, we have a closed circuit.

659
00:35:43,000 --> 00:35:47,000
But if I was to go over to the wall and flip the switch, what would we have?

660
00:35:47,000 --> 00:35:50,000
You'd create an open circuit.

661
00:35:50,000 --> 00:35:51,000
Exactly.

662
00:35:51,000 --> 00:35:56,000
At home, you use devices like switches and circuit breakers and fuses to make open circuits.

663
00:35:58,000 --> 00:36:03,000
The people at Niagara Falls told us that power is generated by water that flows under the falls.

664
00:36:03,000 --> 00:36:04,000
That's cool.

665
00:36:04,000 --> 00:36:08,000
In my class, we watched the fire department demonstrate a simple circuit with their fire truck.

666
00:36:08,000 --> 00:36:10,000
It really helped me to understand how a circuit works.

667
00:36:10,000 --> 00:36:13,000
So are all homes on one series circuit?

668
00:36:13,000 --> 00:36:14,000
Hmm.

669
00:36:14,000 --> 00:36:18,000
Because if one house lost power, doesn't every house lose power?

670
00:36:18,000 --> 00:36:19,000
Yeah.

671
00:36:19,000 --> 00:36:20,000
They're just like Christmas lights.

672
00:36:20,000 --> 00:36:22,000
If one goes out, they all go out.

673
00:36:22,000 --> 00:36:23,000
I don't think that's how it works.

674
00:36:23,000 --> 00:36:24,000
I'll bet it does.

675
00:36:24,000 --> 00:36:26,000
Why do you think all the houses are out across the street?

676
00:36:26,000 --> 00:36:28,000
But every house in our town isn't without power.

677
00:36:28,000 --> 00:36:30,000
Our tree house still has power.

678
00:36:30,000 --> 00:36:32,000
I don't think our neighborhood is on one simple circuit.

679
00:36:32,000 --> 00:36:35,000
I think our house's circuits are complex, too.

680
00:36:35,000 --> 00:36:38,000
When you turn off a light switch, the whole house doesn't go dark.

681
00:36:38,000 --> 00:36:40,000
I think we need to go back to the problem board.

682
00:36:42,000 --> 00:36:46,000
We learned how power is generated at a power plant and how everything runs on a circuit.

683
00:36:46,000 --> 00:36:50,000
We know that a simple circuit is made up of a power source, conductors, and a load.

684
00:36:50,000 --> 00:36:53,000
And we know that our neighborhood does not run on a simple circuit.

685
00:36:53,000 --> 00:36:57,000
I think we need to know a little more about these complex circuits.

686
00:36:57,000 --> 00:36:59,000
Okay, where can we find some more information?

687
00:36:59,000 --> 00:37:00,000
I have an idea.

688
00:37:00,000 --> 00:37:04,000
Let's see if anyone on the NASA White Falls Kids Club has done any research on electrical circuits.

689
00:37:04,000 --> 00:37:07,000
Okay, I'll send them an email and check on our neighbors.

690
00:37:07,000 --> 00:37:10,000
I'll send them an email and check on our NASA White Falls website.

691
00:37:11,000 --> 00:37:13,000
Hey, I found it!

692
00:37:13,000 --> 00:37:17,000
A class from Montreal, Quebec, did some experimentation with complex circuits.

693
00:37:17,000 --> 00:37:19,000
Cool, let's follow them up.

694
00:37:24,000 --> 00:37:28,000
Bonjour, mon nom est Alex Roberts, dans l'école Beacon Hill.

695
00:37:28,000 --> 00:37:31,000
C'est un camionnet avec Mr. Robin, Québec, Canada.

696
00:37:31,000 --> 00:37:37,000
Hi, my name is Alex Roberts, in Beacon Hill School, 5th grade, with Mr. Robin, Québec, Canada.

697
00:37:37,000 --> 00:37:41,000
Hi, can you tell us more about your experiments with circuits?

698
00:37:41,000 --> 00:37:47,000
We're making different types of circuits using D-cell batteries, light bulbs, battery holders, and wires.

699
00:37:47,000 --> 00:37:49,000
What do you mean different types of circuits?

700
00:37:49,000 --> 00:37:55,000
Our job was to experiment on different combinations of circuits and observe what happens.

701
00:37:55,000 --> 00:37:58,000
We made a hypothesis of what we thought would happen.

702
00:37:58,000 --> 00:38:02,000
One student made a light bulb really bright with two batteries and one bulb.

703
00:38:02,000 --> 00:38:05,000
Another student lit two bulbs with just one battery.

704
00:38:05,000 --> 00:38:09,000
He found out that if you unscrewed one of the bulbs, the other went out too.

705
00:38:09,000 --> 00:38:11,000
This is called a series circuit.

706
00:38:11,000 --> 00:38:15,000
Aha! I was right. If one light bulb goes out, they all go out.

707
00:38:15,000 --> 00:38:20,000
Well, our teacher asked us to try and design a circuit with more than one load,

708
00:38:20,000 --> 00:38:25,000
like a bulb buzzer or a motor, that will keep on working if we remove one of the loads.

709
00:38:26,000 --> 00:38:32,000
One student drew a diagram with the same numbers of bulbs and batteries and used more wires going through each bulb.

710
00:38:32,000 --> 00:38:34,000
Did you try unscrewing one light bulb?

711
00:38:34,000 --> 00:38:37,000
Yes. When we unscrewed one of the bulbs, the other stayed lit.

712
00:38:37,000 --> 00:38:41,000
It was almost like the electricity went around the unscrewed bulb to get to the other.

713
00:38:41,000 --> 00:38:43,000
What? That can't be right.

714
00:38:43,000 --> 00:38:46,000
How is that different from the series circuit you made?

715
00:38:46,000 --> 00:38:50,000
In the series circuit, the electricity traveled in a circle through each bulb,

716
00:38:50,000 --> 00:38:53,000
but in a parallel circuit, it traveled to and around each bulb.

717
00:38:53,000 --> 00:38:55,000
Look at these two circuits.

718
00:38:55,000 --> 00:38:59,000
The first one is called a series circuit. It is basically a circle.

719
00:38:59,000 --> 00:39:03,000
When you remove one bulb, the flow of the electricity is interrupted.

720
00:39:03,000 --> 00:39:06,000
The second one is called a parallel circuit.

721
00:39:06,000 --> 00:39:11,000
The electricity goes to each resistor separately and bypasses the ones not connected.

722
00:39:11,000 --> 00:39:15,000
And that's the difference between parallel and series circuit.

723
00:39:15,000 --> 00:39:21,000
Our teacher said that we can make complex circuits by combining parallel and series circuit into one big circuit.

724
00:39:21,000 --> 00:39:23,000
That's what we're going to try next.

725
00:39:23,000 --> 00:39:26,000
Okay. This is great information. Thanks for your help.

726
00:39:26,000 --> 00:39:28,000
Au revoir, les amis.

727
00:39:28,000 --> 00:39:31,000
Bye!

728
00:39:32,000 --> 00:39:34,000
Hey, Matthew, what are you doing?

729
00:39:34,000 --> 00:39:36,000
I'm just playing with these Christmas tree lights.

730
00:39:36,000 --> 00:39:40,000
I guess these lights are wired up in a series circuit because when I take one light bulb out, they all go out.

731
00:39:40,000 --> 00:39:42,000
But not all the lights go out.

732
00:39:42,000 --> 00:39:46,000
I have to take another light bulb in a different part of the strand to get the other lights to go out.

733
00:39:46,000 --> 00:39:49,000
So is it a parallel circuit or a series circuit?

734
00:39:49,000 --> 00:39:51,000
These lights are definitely a series circuit.

735
00:39:51,000 --> 00:39:55,000
But the whole strand is a parallel circuit. Two sets of 50.

736
00:39:55,000 --> 00:39:57,000
I guess it's a combination of both.

737
00:39:57,000 --> 00:40:03,000
Each section is wired in a parallel, but the bulbs within each section are wired up in a series.

738
00:40:03,000 --> 00:40:06,000
Hey, look! Another KSNM report is coming on.

739
00:40:10,000 --> 00:40:13,000
I'm Ted Toon and this is KSNM.

740
00:40:13,000 --> 00:40:18,000
Officials from the power company report that all major circuits appear to be working.

741
00:40:18,000 --> 00:40:23,000
KSNM's own I Am Listening is on the scene at one house still without power.

742
00:40:23,000 --> 00:40:24,000
I Am?

743
00:40:24,000 --> 00:40:28,000
Ted, you could probably see me if my...

744
00:40:28,000 --> 00:40:33,000
cameraman had remembered to bring fresh batteries for the lights.

745
00:40:33,000 --> 00:40:38,000
At the moment, I'm standing outside the home of a Mr. E.

746
00:40:38,000 --> 00:40:42,000
His neighborhood is the only one that has no power tonight.

747
00:40:42,000 --> 00:40:50,000
The power company reports, however, that all overhead lines that were damaged by the recent storm have been repaired.

748
00:40:50,000 --> 00:40:53,000
What is causing the blackout in Mr. E.'s neighborhood?

749
00:40:53,000 --> 00:40:55,000
We may never know.

750
00:40:55,000 --> 00:40:57,000
Back to you, Ted.

751
00:40:57,000 --> 00:40:59,000
Thank you, I Am, for that electrifying account.

752
00:40:59,000 --> 00:41:04,000
I'll bet next month's electric bill that the treehouse detectives can solve this current case.

753
00:41:04,000 --> 00:41:07,000
Current! Ha! Get it? Ha ha ha!

754
00:41:07,000 --> 00:41:11,000
If all the main circuits are working, then the problem must be pretty close to our neighborhood.

755
00:41:11,000 --> 00:41:13,000
Maybe the problem is inside Mr. E.'s house.

756
00:41:13,000 --> 00:41:16,000
What do you want to do, snoop around Mr. E.'s house when he's not there?

757
00:41:16,000 --> 00:41:19,000
We can't do that. We don't even know what we're looking for.

758
00:41:19,000 --> 00:41:21,000
So maybe we should figure out how our houses are wired first.

759
00:41:21,000 --> 00:41:23,000
You mean in a parallel or series circuit?

760
00:41:23,000 --> 00:41:26,000
Exactly. Let's ask Dr. D for help.

761
00:41:26,000 --> 00:41:31,000
Now we've learned all about series and parallel circuits, and we're ready to see how our houses are wired.

762
00:41:31,000 --> 00:41:33,000
The model of the house right here.

763
00:41:33,000 --> 00:41:36,000
How can we tell whether it's wired in series or in parallel?

764
00:41:36,000 --> 00:41:42,000
Well, we know that when something is wired in parallel, when one lamp burns out or is turned off, the rest of them stay on.

765
00:41:42,000 --> 00:41:45,000
Not only that, but the lights that are still on don't change.

766
00:41:45,000 --> 00:41:47,000
They don't get lighter, and they don't get dimmer.

767
00:41:47,000 --> 00:41:51,000
Let's try it. Let's turn one of these lamps off and see what happens.

768
00:41:51,000 --> 00:41:57,000
They must be in parallel, because in series, all of the lights would have gone out when one was turned off.

769
00:41:57,000 --> 00:41:59,000
Why is it important to have a house wired in parallel?

770
00:41:59,000 --> 00:42:05,000
Well, it'd be really annoying if I was playing on the computer, and my dad turned a lamp off, and the computer shut off.

771
00:42:05,000 --> 00:42:10,000
Or if I was in my room, and my light got dimmer because someone else was turning lights on in the house.

772
00:42:10,000 --> 00:42:17,000
Well, as more and more devices are turned on in the house, the number of charges flowing through the circuit increases.

773
00:42:17,000 --> 00:42:24,000
Each device gets just the current that it needs, but the current flowing in the supply wires must supply current to all the devices.

774
00:42:24,000 --> 00:42:29,000
If too many devices are turned on, the current in the supply wires is too great, and the wires get hot.

775
00:42:29,000 --> 00:42:31,000
This is called an overload.

776
00:42:31,000 --> 00:42:33,000
The circuit breaker trips and turns the circuit off.

777
00:42:33,000 --> 00:42:36,000
I guess the circuit breaker is in series with everything else.

778
00:42:36,000 --> 00:42:39,000
When it is turned off, we have an open circuit.

779
00:42:39,000 --> 00:42:41,000
Why would you want everything in the circuit to turn off?

780
00:42:41,000 --> 00:42:45,000
Because if the wires in the walls get too warm, then you'd have a fire on your hands.

781
00:42:45,000 --> 00:42:46,000
That's right.

782
00:42:46,000 --> 00:42:50,000
Now, sometimes an appliance malfunctions and causes a short circuit.

783
00:42:50,000 --> 00:42:53,000
It basically means the two incoming wires touch.

784
00:42:53,000 --> 00:42:56,000
There's a huge current that runs through because it's bypassing the load.

785
00:42:56,000 --> 00:42:59,000
Now, when a short circuit occurs, what happens?

786
00:42:59,000 --> 00:43:01,000
So the circuit breaker opens the circuit, so no harm is done.

787
00:43:01,000 --> 00:43:03,000
That's right, just like this.

788
00:43:03,000 --> 00:43:08,000
So when a circuit breaker is tripped, you have to first fix the problem, then turn the circuit breaker back on.

789
00:43:08,000 --> 00:43:13,000
Just like several wall outlets in a house are connected together and protected by a circuit breaker,

790
00:43:13,000 --> 00:43:20,000
so the houses in a neighborhood are also connected together in this parallel circuit and protected by a big circuit breaker.

791
00:43:20,000 --> 00:43:22,000
So how many houses are in a circuit?

792
00:43:22,000 --> 00:43:24,000
Could be as many as four or five.

793
00:43:24,000 --> 00:43:29,000
Does this mean if there's too much current going into a house in the circuit, the circuit breaker opens the circuit?

794
00:43:29,000 --> 00:43:30,000
That's right.

795
00:43:30,000 --> 00:43:32,000
When the circuit is open, all the houses go dark.

796
00:43:32,000 --> 00:43:34,000
Wow, we may be onto something here.

797
00:43:34,000 --> 00:43:36,000
But what could cause too much current to go to the houses?

798
00:43:36,000 --> 00:43:39,000
I guess the circuit breaker isn't working.

799
00:43:39,000 --> 00:43:43,000
No, I think it's more of a problem with the wires running to the houses.

800
00:43:43,000 --> 00:43:45,000
Maybe there's a short circuit in the wires.

801
00:43:45,000 --> 00:43:46,000
Good thinking.

802
00:43:46,000 --> 00:43:48,000
Why didn't we think of this earlier?

803
00:43:48,000 --> 00:43:51,000
Maybe because the electrical wires in our neighborhood are buried underground.

804
00:43:51,000 --> 00:43:54,000
That way, the short circuit could be hidden from view.

805
00:43:54,000 --> 00:43:56,000
This could be tough.

806
00:43:56,000 --> 00:43:58,000
Hey, Dr. D, have you had any luck with your train?

807
00:43:58,000 --> 00:44:00,000
Nope.

808
00:44:00,000 --> 00:44:04,000
I checked out the power unit on the workbench last night, and it is indeed working.

809
00:44:04,000 --> 00:44:06,000
This is really getting puzzling.

810
00:44:06,000 --> 00:44:08,000
Wait a minute.

811
00:44:08,000 --> 00:44:12,000
Talking about series and parallel circuits reminds me of something else to check on the train.

812
00:44:12,000 --> 00:44:13,000
What's that?

813
00:44:13,000 --> 00:44:16,000
Well, the pieces of track form a series circuit.

814
00:44:16,000 --> 00:44:20,000
If one of the links of track is not properly plugged in, we have an open circuit.

815
00:44:20,000 --> 00:44:21,000
The train won't work.

816
00:44:21,000 --> 00:44:23,000
I'll check on that later.

817
00:44:23,000 --> 00:44:26,000
In the meantime, I think we should revise our hypothesis to

818
00:44:26,000 --> 00:44:31,000
There is an open circuit somewhere between the power source and the houses across the street.

819
00:44:31,000 --> 00:44:33,000
Good luck on solving your mystery.

820
00:44:33,000 --> 00:44:35,000
It sounds like you're getting close.

821
00:44:35,000 --> 00:44:37,000
So what's up?

822
00:44:37,000 --> 00:44:40,000
Why do you think the power is still off across the street?

823
00:44:40,000 --> 00:44:45,000
What would happen if your entire city was wired on one big series circuit?

824
00:44:45,000 --> 00:44:49,000
Is an open circuit keeping Dr. D's train from working?

825
00:44:49,000 --> 00:44:53,000
Do you think the Treehouse Detectives are getting closer to solving the case?

826
00:44:53,000 --> 00:44:58,000
Stay tuned for the final installment of The Case of the Electricity Mystery.

827
00:45:03,000 --> 00:45:06,000
So, we revised our hypothesis to say

828
00:45:06,000 --> 00:45:09,000
Something damaged the power lines in the area where the power is out.

829
00:45:09,000 --> 00:45:10,000
Something?

830
00:45:10,000 --> 00:45:12,000
Boy, that could be anything.

831
00:45:12,000 --> 00:45:14,000
Yes, but let's not give up.

832
00:45:14,000 --> 00:45:17,000
Remember, Dr. D says the answer could be right in front of us.

833
00:45:17,000 --> 00:45:19,000
Let's check out the problem board.

834
00:45:19,000 --> 00:45:23,000
Okay, we know there is a difference between parallel and series circuits.

835
00:45:23,000 --> 00:45:27,000
And we also know that rooms in our homes are wired in parallel circuits.

836
00:45:27,000 --> 00:45:33,000
Houses in a neighborhood are connected together in parallel, much like the rooms in our houses.

837
00:45:33,000 --> 00:45:37,000
We need to know something can go wrong with power lines and cause an outage.

838
00:45:37,000 --> 00:45:40,000
Remember what Dr. D said about short circuits?

839
00:45:40,000 --> 00:45:43,000
We need to know if there is a short circuit across the street.

840
00:45:43,000 --> 00:45:47,000
Oh look, a KSNN report. Maybe we'll get another clue.

841
00:45:50,000 --> 00:45:54,000
Ted Toon here with this special report.

842
00:45:54,000 --> 00:45:59,000
We've just been informed that I Am Listening has a new clue in the mystery power outage story.

843
00:45:59,000 --> 00:46:01,000
I Am, are you there?

844
00:46:01,000 --> 00:46:08,000
Ted, we've just been informed that authorities are on the lookout for someone named Public Damage.

845
00:46:08,000 --> 00:46:17,000
Power company officials feel that Public Damage is probably responsible for the power outage here in Mr. E's neighborhood.

846
00:46:17,000 --> 00:46:24,000
It is unknown at this time what Public Damage looks like or what his or her motives might be.

847
00:46:24,000 --> 00:46:29,000
I Am, are you there? We seem to have lost contact. Oh, wait.

848
00:46:29,000 --> 00:46:40,000
Ted, this just in. I've fallen into a hole in Mr. E's yard. I'm covered with mud. I'm getting very cold.

849
00:46:40,000 --> 00:46:42,000
Back to you.

850
00:46:42,000 --> 00:46:45,000
Thanks, I Am. There you have it, ladies and gentlemen.

851
00:46:45,000 --> 00:46:49,000
Kids Science News Network will go to any depth to report on a story.

852
00:46:49,000 --> 00:46:53,000
And now we join our regularly scheduled program, Already in Progress.

853
00:46:53,000 --> 00:46:56,000
I don't get it. What is Public Damage?

854
00:46:56,000 --> 00:46:59,000
Remember that email that we received from the power company?

855
00:46:59,000 --> 00:47:00,000
Yes.

856
00:47:00,000 --> 00:47:03,000
Well, they said that we could go along with a utility crew and see what they do.

857
00:47:03,000 --> 00:47:06,000
Maybe the crew could tell us more about Public Damage.

858
00:47:06,000 --> 00:47:07,000
Good idea.

859
00:47:07,000 --> 00:47:09,000
Let's get up and go. I'll set it up.

860
00:47:13,000 --> 00:47:19,000
Hi, Catherine. Hi, Bianca. I'm Warren Walker with Dominion Power.

861
00:47:19,000 --> 00:47:23,000
I understand you want to learn a little bit more about what we do and about Public Damage.

862
00:47:23,000 --> 00:47:25,000
Yes. What is Public Damage?

863
00:47:25,000 --> 00:47:28,000
Public Damage is when a person causes a power outage.

864
00:47:28,000 --> 00:47:35,000
It might be as far as a car hitting a utility pole or somebody digging in their backyard hitting an underground cable or even vandalism.

865
00:47:35,000 --> 00:47:39,000
So if there's public damage to a power line, it's your job to fix it.

866
00:47:39,000 --> 00:47:42,000
Exactly. We have crews that will go out and restore service to the customer.

867
00:47:42,000 --> 00:47:44,000
Come on. Let me show you some things.

868
00:47:46,000 --> 00:47:48,000
Do you know how power gets to your neighborhood?

869
00:47:48,000 --> 00:47:52,000
Yes. We know that it is transmitted from the power plant to our homes.

870
00:47:52,000 --> 00:47:59,000
Exactly. When the generator spins in the power plant, the voltage comes out at about 230,000 volts.

871
00:47:59,000 --> 00:48:02,000
Isn't that a lot higher voltage than what is used in our homes?

872
00:48:02,000 --> 00:48:03,000
Absolutely.

873
00:48:03,000 --> 00:48:07,000
Then why does it have to be such high voltage at the power plant?

874
00:48:07,000 --> 00:48:12,000
Electricity travels much easier over long distances at a higher voltage.

875
00:48:12,000 --> 00:48:17,000
The high voltage electricity travels through wires that string all across the area.

876
00:48:17,000 --> 00:48:24,000
Eventually, these high voltage power lines go into a fenced off area full of large metal boxes, fat wires and other stuff.

877
00:48:24,000 --> 00:48:27,000
These areas are called substations.

878
00:48:27,000 --> 00:48:33,000
In a substation, the very high voltage electricity is changed into lower voltage electricity.

879
00:48:33,000 --> 00:48:37,000
Even though the voltage is lower, it is still too high for you to use in your home.

880
00:48:37,000 --> 00:48:40,000
Is there another place where the voltage is even lower?

881
00:48:40,000 --> 00:48:43,000
That's right. There is. It's in your neighborhood.

882
00:48:43,000 --> 00:48:47,000
If you look up on the power pole, you'll see a round, gray, looks like a can.

883
00:48:47,000 --> 00:48:49,000
That's a transformer.

884
00:48:49,000 --> 00:48:55,000
They're called transformers because they transform the electricity to just the right voltage for your home.

885
00:48:55,000 --> 00:48:59,000
In other neighborhoods, the wires are underground.

886
00:48:59,000 --> 00:49:02,000
In that case, the transformer is a big green box.

887
00:49:02,000 --> 00:49:05,000
What is the voltage used for our homes?

888
00:49:05,000 --> 00:49:10,000
Eventually, the voltage is stepped down to 240 volts for your large appliances.

889
00:49:10,000 --> 00:49:13,000
That would be like your air conditioner and your clothes dryer.

890
00:49:13,000 --> 00:49:18,000
And then 120 volts, and that would run like your hair dryer or your microwave or your toaster.

891
00:49:18,000 --> 00:49:22,000
Is there a way that we can measure how much energy is used in our homes?

892
00:49:22,000 --> 00:49:26,000
Yes, there's a meter on the side of your house called a kilowatt hour meter.

893
00:49:26,000 --> 00:49:28,000
What is a kilowatt hour?

894
00:49:28,000 --> 00:49:31,000
A kilowatt hour is a measurement of energy.

895
00:49:31,000 --> 00:49:36,000
A kilo means 1,000, so that's 1,000 watts of kilowatt.

896
00:49:36,000 --> 00:49:39,000
A toaster is a one kilowatt device.

897
00:49:39,000 --> 00:49:43,000
If it were running for one hour, it would use a kilowatt hour of energy.

898
00:49:43,000 --> 00:49:46,000
You can figure out how much energy an appliance will use.

899
00:49:46,000 --> 00:49:53,000
You just take the rating of the appliance in kilowatts, the time it is on continuously, and multiply it.

900
00:49:53,000 --> 00:50:00,000
If a microwave used one kilowatt of power per hour for three hours, that would equal three kilowatt hours.

901
00:50:00,000 --> 00:50:05,000
If we had a three kilowatt device that ran for one hour, would it be the same amount of energy?

902
00:50:05,000 --> 00:50:10,000
Yes, it would, and you can also figure out how much it would cost to run that appliance.

903
00:50:10,000 --> 00:50:11,000
How do we do that?

904
00:50:11,000 --> 00:50:14,000
Ask your parents to show you your utility bill.

905
00:50:14,000 --> 00:50:17,000
On the bill, it will show what you're being charged per kilowatt hour.

906
00:50:17,000 --> 00:50:22,000
For example, let's say the charge per kilowatt hour is five cents.

907
00:50:22,000 --> 00:50:25,000
We have a toaster, a hair dryer, and a microwave.

908
00:50:25,000 --> 00:50:29,000
We'll say that each of these appliances is a one kilowatt device.

909
00:50:29,000 --> 00:50:32,000
How much would it cost to run these appliances for two hours?

910
00:50:32,000 --> 00:50:38,000
Well, a one kilowatt appliance running for two hours would equal two kilowatt hours of energy.

911
00:50:38,000 --> 00:50:42,000
If there were three appliances, that would be a total of six kilowatt hours.

912
00:50:42,000 --> 00:50:44,000
Right, so find the price.

913
00:50:44,000 --> 00:50:49,000
We would multiply kilowatt hours times the cents per kilowatt hour.

914
00:50:49,000 --> 00:50:56,000
That's six kilowatt hours times five cents per kilowatt hour, or 30 cents.

915
00:50:56,000 --> 00:51:02,000
And so by using a little math, you can calculate what each appliance in your home will cost to run.

916
00:51:02,000 --> 00:51:06,000
You can learn more about calculating energy costs at the NASA Wi-Fi's website.

917
00:51:06,000 --> 00:51:08,000
Thanks for telling us about it.

918
00:51:08,000 --> 00:51:13,000
Hey, look over there. I wonder what that person's painting on the grass.

919
00:51:13,000 --> 00:51:15,000
Oh, that's Mr. Utility.

920
00:51:15,000 --> 00:51:18,000
He provides a service to locate underground cable for people.

921
00:51:18,000 --> 00:51:20,000
Why don't you ask him about his job?

922
00:51:20,000 --> 00:51:22,000
Great, we'll do that.

923
00:51:22,000 --> 00:51:24,000
Thanks for telling us what you do, Mr. Walk.

924
00:51:24,000 --> 00:51:25,000
Sure, I'll see you later.

925
00:51:25,000 --> 00:51:26,000
Bye.

926
00:51:26,000 --> 00:51:27,000
Bye-bye.

927
00:51:27,000 --> 00:51:28,000
Hi, kids.

928
00:51:28,000 --> 00:51:30,000
Hi, can we ask what are you doing?

929
00:51:30,000 --> 00:51:36,000
Sure, I'm working lines on this property to let everyone know that there's an underground power line buried there.

930
00:51:36,000 --> 00:51:39,000
The homeowners had called us up because they're planning on putting in a fence.

931
00:51:39,000 --> 00:51:42,000
They were afraid they would damage some underground utilities.

932
00:51:42,000 --> 00:51:48,000
Hmm, I wonder what would happen if someone was putting up a fence and they didn't call you.

933
00:51:48,000 --> 00:51:49,000
Hmm, that could be a problem.

934
00:51:49,000 --> 00:51:54,000
Someone can easily damage an underground utility simply because they didn't know it was there.

935
00:51:54,000 --> 00:51:56,000
Would that be considered public damage?

936
00:51:56,000 --> 00:51:58,000
Yes, it sure would.

937
00:51:58,000 --> 00:52:01,000
But Mr. E doesn't have any painted lines in his yard.

938
00:52:01,000 --> 00:52:03,000
And he just finished putting up a fence.

939
00:52:03,000 --> 00:52:05,000
And his house is without power.

940
00:52:05,000 --> 00:52:08,000
I don't remember seeing any lines in his yard either.

941
00:52:08,000 --> 00:52:10,000
Hmm, let me check my list.

942
00:52:10,000 --> 00:52:12,000
No, I don't see a Mr. E on my list.

943
00:52:12,000 --> 00:52:14,000
And you say he's without power?

944
00:52:14,000 --> 00:52:17,000
Yes, in fact, several houses are without power.

945
00:52:18,000 --> 00:52:20,000
Jim to repair crew.

946
00:52:20,000 --> 00:52:22,000
This is the repair crew. Go ahead.

947
00:52:22,000 --> 00:52:24,000
We've got a homeowner here who has put in a fence.

948
00:52:24,000 --> 00:52:26,000
He didn't contact us.

949
00:52:26,000 --> 00:52:28,000
I think we've got a power break here.

950
00:52:28,000 --> 00:52:31,000
Maybe there's public damage to the underground line.

951
00:52:31,000 --> 00:52:33,000
We've had a report of it out at several houses.

952
00:52:33,000 --> 00:52:35,000
We'll check it out. Thank you.

953
00:52:36,000 --> 00:52:38,000
Hey kids, what's happening?

954
00:52:38,000 --> 00:52:42,000
Mr. E, did you call Mr. Utility to find out where your underground power lines were

955
00:52:42,000 --> 00:52:44,000
before you started putting up your fence?

956
00:52:44,000 --> 00:52:46,000
Ah, what do you mean?

957
00:52:46,000 --> 00:52:48,000
Mr. E, you should have called us.

958
00:52:48,000 --> 00:52:51,000
I could have easily shown you where the underground power line was.

959
00:52:51,000 --> 00:52:53,000
And you could have prevented this power outage.

960
00:52:53,000 --> 00:52:56,000
Oh man, if I'd have known I was supposed to call you, I would have.

961
00:52:56,000 --> 00:52:59,000
Doesn't Mr. E look kind of familiar?

962
00:52:59,000 --> 00:53:02,000
Hey man, next time I promise to give you a call, okay?

963
00:53:02,000 --> 00:53:05,000
Mr. E, my crews will make repairs and we'll get the lights back on.

964
00:53:05,000 --> 00:53:07,000
See you later, treehouse detectives.

965
00:53:07,000 --> 00:53:09,000
Bye!

966
00:53:14,000 --> 00:53:17,000
At first we thought it was lightning that caused the power outage.

967
00:53:17,000 --> 00:53:20,000
We tested the hypothesis and revised it several times.

968
00:53:20,000 --> 00:53:22,000
Eventually we found a short circuit in Mr. E's house.

969
00:53:22,000 --> 00:53:24,000
Good work, guys.

970
00:53:24,000 --> 00:53:28,000
Hey Dr. D, did you check the train tracks to make sure all the connections were connected properly?

971
00:53:28,000 --> 00:53:30,000
Yes, I did.

972
00:53:30,000 --> 00:53:32,000
I pushed them all in carefully,

973
00:53:32,000 --> 00:53:36,000
and then I checked the connection with an electrical meter to make sure there wasn't an open circuit.

974
00:53:36,000 --> 00:53:40,000
Everything checked out just fine, but it's still not working.

975
00:53:40,000 --> 00:53:44,000
I even took the engine to a friend's house to try it on his track, and it worked as well.

976
00:53:44,000 --> 00:53:46,000
This is really frustrating.

977
00:53:46,000 --> 00:53:51,000
I bet with our experience in the electrical mystery, we could help you solve your train problem.

978
00:53:51,000 --> 00:53:54,000
There are so many things that can go wrong with your train,

979
00:53:54,000 --> 00:53:57,000
so we have to be sure to examine the variables one at a time.

980
00:53:57,000 --> 00:54:00,000
Let's use the causes of electrical outage to help us.

981
00:54:00,000 --> 00:54:04,000
Well, we know that your problem wasn't the storm, because you still have power in your wall outlet,

982
00:54:04,000 --> 00:54:07,000
and I don't think it was an inside storm.

983
00:54:07,000 --> 00:54:11,000
And you've checked the equipment, both the train and the power unit,

984
00:54:11,000 --> 00:54:14,000
and you've checked the track itself to make sure it was a complete circuit.

985
00:54:14,000 --> 00:54:17,000
I wonder if public damage could be a problem.

986
00:54:17,000 --> 00:54:21,000
But who could cause damage and to what?

987
00:54:21,000 --> 00:54:24,000
Well, wait a minute. What's Bernie doing?

988
00:54:24,000 --> 00:54:26,000
What do you know? Look at this.

989
00:54:26,000 --> 00:54:31,000
An open circuit of the extension cord, and it's wired in series with everything else.

990
00:54:31,000 --> 00:54:33,000
Nothing else is going to work.

991
00:54:33,000 --> 00:54:36,000
Good thing it's not a short circuit, or else we'd all be in the dark.

992
00:54:36,000 --> 00:54:41,000
But if your extension cord was bad, then how did you get the power unit to work when you checked it?

993
00:54:41,000 --> 00:54:45,000
That's because I unplugged it from the extension cord and plugged it into my workbench.

994
00:54:45,000 --> 00:54:47,000
I didn't even consider the extension cord.

995
00:54:47,000 --> 00:54:50,000
When I plugged the power unit in someplace else,

996
00:54:50,000 --> 00:54:53,000
I changed one of the variables without even thinking about it.

997
00:54:53,000 --> 00:54:56,000
Just like we didn't even consider the underground cables at first.

998
00:54:56,000 --> 00:54:59,000
Let's plug it into a good extension cord and try it.

999
00:55:05,000 --> 00:55:07,000
Here it goes.

1000
00:55:07,000 --> 00:55:10,000
Yay!

1001
00:55:12,000 --> 00:55:17,000
Scientists, and even retired scientists, need to make sure they don't assume anything.

1002
00:55:17,000 --> 00:55:21,000
We always need to keep our eyes open all the time.

1003
00:55:21,000 --> 00:55:25,000
That's right. You can find the clue in the most unlikely circumstances,

1004
00:55:25,000 --> 00:55:28,000
even in a slobbering St. Bernard.

1005
00:55:32,000 --> 00:55:34,000
Come on, let's go!

1006
00:55:37,000 --> 00:55:39,000
All right, all right.

1007
00:56:08,000 --> 00:56:10,000
Yeah!

1008
00:56:19,000 --> 00:56:21,000
All right, all right.

1009
00:56:23,000 --> 00:56:28,000
The NASA Y-Files is made possible through the generous support of SeaWorld and Bush Gardens

1010
00:56:28,000 --> 00:56:34,000
and the NASA Langley Research Center's Aerospace Vehicle Systems Technology Program Office.