00:00How do compasses work?
00:04Compasses have helped lost souls find their way home for more than 2,000 years.
00:08But how does a little metal needle actually know which way is north?
00:13In a sense, the Earth itself is a giant magnet.
00:16It has a north pole and a south pole,
00:19and those poles can interact with other magnets in the same way that the magnets on your refrigerator can.
00:24Opposite poles attract, while like poles repel.
00:27The needle in your compass is also a tiny magnet,
00:31made from magnetic rock like iron and suspended in liquid so that it can swivel freely.
00:36And so, when you hold your compass level,
00:38the north pole of the needle naturally aligns with the opposite pole of the Earth's magnetic field,
00:43a spot on the top of the globe that we call magnetic north.
00:47Unfortunately for some explorers,
00:49Earth's magnetic north pole doesn't exactly align with the geographic north pole,
00:53otherwise known as true north.
00:55While true north always sits at the top of the Earth's axis in the middle of the Arctic Ocean,
01:00the magnetic north pole is about 1,000 miles south from Canada.
01:03To make things even more complicated,
01:05magnetic north has an annoying habit of moving around as our planet's magnetic field warps over time.
01:11By some estimates, the magnetic north pole has moved more than 600 miles towards Siberia in the last hundred years.
01:18It may not be 100% accurate, but the swiveling little magnet in your compass is still a pretty reliable
01:25bet for finding your way home.
01:27How compasses work? Just another one of life's little mysteries.
01:30How do you know the language?
01:30The playgroup is still a pretty serious.
01:31It'll be a great job.
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