Optics & Ocean Science
Why Is the Ocean Blue?
Water is not actually clear. It absorbs red and yellow light and scatters blue. In a glass this is undetectable, but across miles of ocean depth it becomes vivid blue.
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Earth & Oceans
Why Is Sea Water Salty?
The ocean is salty because rivers continuously wash dissolved minerals from rocks into the sea, while evaporation removes water but leaves the salt behind.
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Earth & Space
Why Do Tides Happen?
Tides happen because the moon's gravity pulls on Earth's oceans unevenly, creating two tidal bulges that coastlines rotate through each day.
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