Compass Brain Freeze
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Transcript
| Line | From | To | |
|---|---|---|---|
-BELL RINGS -Almost there! | 0:00:02 | 0:00:04 | |
Ms Hucklebuck! | 0:00:04 | 0:00:06 | |
That's it! That's my lucky tennis ball! | 0:00:06 | 0:00:10 | |
-Jonathan! -Actually, it's Colin! | 0:00:10 | 0:00:13 | |
THUD | 0:00:14 | 0:00:16 | |
Oh, dear. | 0:00:17 | 0:00:19 | |
It's not like Colin to be this late. | 0:00:19 | 0:00:21 | |
Maybe the pressure finally got to him and he gave up. | 0:00:21 | 0:00:24 | |
-KNOCKING -Help! I'm stuck in the pipes! | 0:00:24 | 0:00:27 | |
-BOTH: -You're stuck in the pipes? | 0:00:27 | 0:00:29 | |
BELL RINGS | 0:00:29 | 0:00:31 | |
Positions! | 0:00:31 | 0:00:32 | |
This is... | 0:00:32 | 0:00:33 | |
..the floor manager. | 0:00:40 | 0:00:42 | |
Stand by! | 0:00:45 | 0:00:47 | |
-BOTH: -It's time for... | 0:00:51 | 0:00:53 | |
Today we're asking, how does a compass work? | 0:00:56 | 0:00:59 | |
The first compass was invented in China during the Han Dynasty, | 0:00:59 | 0:01:03 | |
about 3,000 years ago. | 0:01:03 | 0:01:05 | |
A compass is a lightweight magnet balanced on a pivot | 0:01:05 | 0:01:08 | |
which we call a needle. | 0:01:08 | 0:01:09 | |
No matter where you stand on Earth, a compass will point towards | 0:01:11 | 0:01:14 | |
the North Pole. | 0:01:14 | 0:01:15 | |
For centuries, this simple piece of equipment | 0:01:15 | 0:01:17 | |
helped seafarers navigate the globe | 0:01:17 | 0:01:20 | |
and led to the Age of Discovery. | 0:01:20 | 0:01:22 | |
Speaking of discovery, we better go off and find Colin. | 0:01:22 | 0:01:26 | |
See you shortly! | 0:01:26 | 0:01:27 | |
And we're clear! | 0:01:29 | 0:01:31 | |
I always wanted to say that. | 0:01:31 | 0:01:33 | |
OK, Colin, I think I've got your location pinned down. | 0:01:33 | 0:01:37 | |
What can you see in there? | 0:01:37 | 0:01:39 | |
I can see a T-junction up ahead. | 0:01:39 | 0:01:41 | |
There's plenty of dust and cobwebs and there's an awful lot | 0:01:41 | 0:01:44 | |
of tennis balls. | 0:01:44 | 0:01:45 | |
Rawr! | 0:01:45 | 0:01:47 | |
Aah! | 0:01:47 | 0:01:48 | |
Get me out of here! | 0:01:48 | 0:01:50 | |
BELL RINGS | 0:01:50 | 0:01:51 | |
And we're live in 5, 4, 7, 33. | 0:01:51 | 0:01:55 | |
So, tell us, Dr Knowles, how on earth does a compass work? | 0:02:00 | 0:02:03 | |
It's all because of the Earth's magnetic field. | 0:02:03 | 0:02:06 | |
Convection currents in the liquid layers of the Earth's interior | 0:02:06 | 0:02:09 | |
generate an electrical charge, a bit like a giant battery. | 0:02:09 | 0:02:13 | |
Because the Earth rotates on its axis, | 0:02:13 | 0:02:15 | |
this charge aligns itself with the Earth's poles, | 0:02:15 | 0:02:18 | |
creating a positive charge at one end | 0:02:18 | 0:02:20 | |
and a negative charge at the other. | 0:02:20 | 0:02:22 | |
Just like a magnet. | 0:02:22 | 0:02:24 | |
That's magnet-ificent. | 0:02:26 | 0:02:29 | |
Ha-ha-ha! | 0:02:29 | 0:02:30 | |
But did you know that there are actually two North Poles? | 0:02:30 | 0:02:34 | |
You what now? Two North Poles? | 0:02:34 | 0:02:36 | |
Because the Earth's magnetic field can vary, | 0:02:36 | 0:02:39 | |
the exact location of magnetic north is always changing. | 0:02:39 | 0:02:43 | |
Right now, it lies in northern Canada - | 0:02:43 | 0:02:45 | |
about 1,600 kilometres from true north. | 0:02:45 | 0:02:48 | |
That must be very confusing for anyone living there. | 0:02:48 | 0:02:51 | |
So now you know how a compass works. | 0:02:54 | 0:02:56 | |
Way-hey! See you next time! | 0:02:56 | 0:02:59 | |
Please hurry up! I think I've got company! | 0:03:01 | 0:03:05 | |
Hang in there, Colin! We'll get you out soon! | 0:03:05 | 0:03:08 | |
OK, if he bears 23 degrees... | 0:03:08 | 0:03:10 | |
'I wonder what this big red button does. | 0:03:10 | 0:03:12 | |
'I probably shouldn't press it. | 0:03:12 | 0:03:14 | |
'Oh, I really want to though. | 0:03:14 | 0:03:16 | |
'Oh, look, I just pressed it.' | 0:03:16 | 0:03:18 | |
Whoa! | 0:03:19 | 0:03:22 | |
Aah! | 0:03:22 | 0:03:23 | |
Aargh! | 0:03:25 | 0:03:27 | |
Aargh! | 0:03:27 | 0:03:30 | |
Colin, you're safe! | 0:03:30 | 0:03:31 | |
Ow! | 0:03:31 | 0:03:32 | |
Oh, crumpets. | 0:03:34 | 0:03:37 | |
Oh, look, you found it. | 0:03:37 | 0:03:39 | |
Oh, what would I do without you, McCork? | 0:03:39 | 0:03:42 | |
What can I say, Mrs Hucklebadger? I do my best. | 0:03:42 | 0:03:44 | |
Oh... | 0:03:44 | 0:03:46 | |
Just typical! | 0:03:46 | 0:03:48 | |
Brain Freeze! | 0:04:00 | 0:04:01 |