0:00:02 > 0:00:06Oh, I love thunderstorms. They're so exciting.
0:00:06 > 0:00:10Oh, I just hope it doesn't knock the power out again, Doctor.
0:00:10 > 0:00:12Not to worry, Colin. There's no chance of...
0:00:12 > 0:00:14THUNDER RUMBLES
0:00:14 > 0:00:15..that happening.
0:00:15 > 0:00:18Oh, crumpets! How are we going to do the show?
0:00:18 > 0:00:20Hey!
0:00:20 > 0:00:21How's it going, everyone?
0:00:21 > 0:00:23Look what happened to me.
0:00:23 > 0:00:24Ooh! Whoa!
0:00:24 > 0:00:25And one for you.
0:00:25 > 0:00:27Oh, this is deadly.
0:00:27 > 0:00:30Are you thinking what I'm thinking?
0:00:30 > 0:00:32- BELL RINGS - Positions!
0:00:32 > 0:00:35This is Brain Freeze
0:00:35 > 0:00:38with Dr Knowles,
0:00:38 > 0:00:41Professor McCork,
0:00:41 > 0:00:43Colin the floor manager
0:00:43 > 0:00:46and Ms Hucklebuck.
0:00:46 > 0:00:48Stand by!
0:00:48 > 0:00:51Come on, everybody!
0:00:53 > 0:00:54BOTH: It's time for...
0:00:57 > 0:01:00Today we're asking...
0:01:00 > 0:01:02Lightning is a giant spark of electricity
0:01:02 > 0:01:06usually created inside a cloud during a thunderstorm.
0:01:06 > 0:01:08Cold air containing ice crystals
0:01:08 > 0:01:10and hot air containing water droplets
0:01:10 > 0:01:14come into contact, creating a build-up of electrical charge.
0:01:14 > 0:01:15When the negative charge
0:01:15 > 0:01:17at the bottom of the cloud builds up,
0:01:17 > 0:01:19it will do everything in its power
0:01:19 > 0:01:22to connect with a positive charge elsewhere.
0:01:22 > 0:01:25It can find this positive charge above...
0:01:25 > 0:01:27or below,
0:01:27 > 0:01:29resulting in spectacular lightning strikes.
0:01:29 > 0:01:31I love it.
0:01:31 > 0:01:35Kazaam! Take that! Boom!
0:01:35 > 0:01:37It's becoming a little charged in here, too.
0:01:37 > 0:01:39I think we need a break.
0:01:39 > 0:01:41And we're clear.
0:01:43 > 0:01:45Oh, battery's dead.
0:01:45 > 0:01:47Professor, would you mind
0:01:47 > 0:01:49- charging this?- Not a problem.
0:01:49 > 0:01:51Yes, and my phone, too.
0:01:51 > 0:01:52There you go.
0:01:52 > 0:01:55- And be a dear, McCork, and blend my smoothie.- Oh, yeah.
0:01:55 > 0:01:57And this radio is a bit dead.
0:01:57 > 0:01:59I've got so much other things.
0:01:59 > 0:02:01I've got a Hoover that I need you to have a look at.
0:02:01 > 0:02:04This is fantastic. Free power!
0:02:04 > 0:02:07It might be free, but it won't last.
0:02:08 > 0:02:10Oh.
0:02:10 > 0:02:12Huh?
0:02:12 > 0:02:14Uh-oh. No more power.
0:02:14 > 0:02:16Lucky I built this backup generator.
0:02:16 > 0:02:17It's time to start pedalling!
0:02:17 > 0:02:20- BELL RINGS - Positions!
0:02:20 > 0:02:22MUSIC PLAYS SLOWLY
0:02:22 > 0:02:25Today's Big Answer.
0:02:25 > 0:02:27So, what about this one, Dr Knowles?
0:02:27 > 0:02:30Is it true that lightning never strikes twice?
0:02:30 > 0:02:33With an estimated eight million lightning strikes
0:02:33 > 0:02:35around the world every day,
0:02:35 > 0:02:36it certainly is possible
0:02:36 > 0:02:40that lightning can strike the same place more than once.
0:02:40 > 0:02:43These bolts heat the air, causing it to expand explosively
0:02:43 > 0:02:46before rapidly contracting as it cools.
0:02:46 > 0:02:49This causes the familiar crack and rumble we know as thunder.
0:02:49 > 0:02:53But why does the thunder come after the lightning?
0:02:53 > 0:02:56That's because light travels faster than sound.
0:02:56 > 0:02:58We see the lightning strike almost instantly,
0:02:58 > 0:03:01but it takes approximately three seconds
0:03:01 > 0:03:02for the sound to travel 1km.
0:03:05 > 0:03:08This way we can calculate how far away the storm is
0:03:08 > 0:03:11by counting the time between lightning and thunder.
0:03:11 > 0:03:13One, two...
0:03:13 > 0:03:15- THUNDERCLAP - Yikes!
0:03:15 > 0:03:16This one's pretty near, so.
0:03:16 > 0:03:19- Cool! - See you next time, everyone.
0:03:22 > 0:03:26- Well, I hope you lot learned something today.- Oh, we have, Colin.
0:03:26 > 0:03:28I'll never take electricity for granted again.
0:03:28 > 0:03:32And, you know, it's actually kind of fun without it.
0:03:32 > 0:03:34WHIRRING
0:03:34 > 0:03:37Oh, look. The power's back on.
0:03:39 > 0:03:41Video games, anyone?
0:03:41 > 0:03:43OTHERS: Yay!
0:03:43 > 0:03:45What's a video game?
0:03:45 > 0:03:46Oh, crumpets.
0:03:46 > 0:03:49Will we ever learn?
0:03:49 > 0:03:50Oh!