How the mainspring made portable clocks possible

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A coiled spring made small clocks possible

Early mechanical clocks were powered by large hanging weights. In the early 1400s, the mainspring provided another way to store energy: a tightly wound spring. This made much smaller clocks possible.

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Aluminum is far more common in Earth's crust

Aluminum makes up 8.23% of Earth's crust by mass, but only 1.59% of Earth as a whole. Its strong attraction to oxygen keeps much of it bound in oxygen-rich minerals in the crust.

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Mauritius’s sea zone far exceeds its land area

~1,000×

Mauritius has 2,040 square kilometres of land and a maritime zone of about 2 million square kilometres—nearly 1,000 times its land area.

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