Only 12,000 years ago there was a species closely related to modern humans called Homo floresiensis that had been living on an Indonesian Island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
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When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
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Sound travels about 4 times faster in water than in air.
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If the chemical sodium is dropped into water it will immediately and violently explode.
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4.5 pounds of sunlight strike the Earth each day.
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During photosynthesis, plants emit light humans can’t see, but NASA can see that light from space - and they've even made maps of it!
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Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
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Scientists concluded that the chicken came first, not the egg, because the protein which makes the egg shells is only produced by hens.
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