Volcanic rocks contain small bits of iron oxide that get magnetised in the direction of the Earth's magnetic field as they cool. Comparing rocks of different ages reveals the magnetic history of our planet.
Watch the full second lecture of the series: [ Ссылка ]
James Jackson gave the 1995 Christmas Lectures "Planet Earth: An Explorer's Guide" about the inner workings of planet Earth.
The second lecture "Secrets of the Deep", where this clip is from, is about the crucial role plate tectonics play in the structure of our oceans and continents.
Watch the full series:
[ Ссылка ]
Christmas Lectures are a popular children's science show broadcast every year on the BBC. As such they fall under YouTube's 'Made for Kids' category, which means that some common features are disabled on this video, such as comments, cards and end screens.
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