A Van de Graaff generator is used to demonstrate how lightning rods work!
Announcer: Frostbite Theater presents... Cold Cuts! No baloney!
Joanna and Steve: Just science!
Joanna: Hi! I'm Joanna!
Steve: And I'm Steve!
Joanna: And this is a Van de Graaff generator!
Steve: And this is called a grounding dome because it's attached to the earth through this wire.
Steve: When we turn the Van de Graaff generator on electrons jump between the two domes, creating sparks!
Van de Graaff: Snap! Snap!
Joanna: This is like making our own mini-thunderstorm!
Steve: Charges tend to gather on rounded surfaces and they tend to jump off of points. That's why these domes are round. We want the charge to collect on them.
Joanna: A lightning rod is a pointy piece of metal that's used to protect buildings and other structures from lightning. A lightning rod is not used to attract lightning. The hope is, rather, the lightning rod will bleed charge off of the storm so the lightning doesn't strike. If the lightning does strike, however, the lightning will flow through the lightning rod and into the ground and not into something else, like a house.
Steve: These nails are pointy pieces of metal that act like lightning rods. If we point them towards the dome, the sparks stop. If we take them away, it starts up again.
If you watch some of our other videos, you may notice Joanna and I walking around with these nails. We use them to bleed charge off the dome so it doesn't build up enough for it to strike.
Now, there's still electricity flowing from the dome, through the air, through the nail, into me and into the ground, but it's doing it a little bit at a time.
Discharging the dome a little bit at a time doesn't hurt.
Discharging the dome all at once...
Van de Graaff: Snap!
Steve: ...does hurt!
Joanna: Thanks for watching! I hope you'll join us again soon for another experiment!
Steve: Next time, can we do an experiment please that doesn't hurt so much?
Steve: Thank you!
Van de Graaff: Snap!
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