Science Education
(Likes Attract, Opposites Repel)
(Lightning Rods)
Thunder and lightning are created using a Van de Graaff generator!
Announcer: Frostbite Theater presents... Cold Cuts! No baloney!
Joanna and Steve: Just science!
Joanna: Hi! I'm Joanna!
Steve: And I'm Steve!
Joanna: This device is called a Van de Graaff generator and one thing that's really fun to is to use it to make really big sparks!
The Van de Graaff generator dumps electrons on this dome. The more electrons there are, the more 'uncomfortable' they become. Now, remember, electrons carry a negative electrical charge and like charges repel. The electrons try to spread out the best that they can.
Steve: This dome is attached to the earth through this wire and the earth is a whole lot larger and either one of these domes, so it has a lot more room for the electrons to spread around. Eventually, so many electrons will gather on this dome that they'll be able to jump through the air to this dome. Once they're here, they'll go through the wire and into the earth, where they can spread out as much as they like.
Van de Graaff: Snap! Snap! Snap!
Joanna: The sparks that you see are essentially baby lightning and the sounds that you hear are essentially baby thunder. The sparks are hotter than the Steve: urface of the sun and they heat the air as they pass though it. The sudden expansion of this heated air causes a shock wave that we hear as thunder.
Steve: Now, in a real thunderstorm, you see the lightning...
...and then you hear the thunder, but, do you know why, now we're seeing it and hearing it at the same time?
Joanna: Light travels a lot faster than sound. Sound can travel about one mile in five seconds. And, while that's pretty fast, light can travel about a million miles in the same amount of time.
Steve: So, while the light from the spark reaches our eyes before the sound reaches our ears, we're so close to it, we can't tell the difference. If lightning were to come through the ceiling and strike the table in front of us right now, we'd Steve: ee that and see it at the same time, too.
And then, we'd probably die.
So, let's hope that doesn't happen!
Joanna: Thanks for watching! I hope you'll join us again soon for another experiment!
Steve: Sparks in the dark?
Joanna: Sparks in the dark!
Van de Graaff: Snap! Snap! Snap! Snap!
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