Sediment is the accumulation of sand and dirt that settles in the bottom of lakes. Sediment is also what you get in the bottom of a glass of iced tea when the sugar doesn’t all dissolve.The noun sediment comes from the Latin word sedere, meaning “to settle,” or “sit.” Sediment is the little bits of solids that sink to the bottom of a container of liquid, whether that container is a body of water or a holding tank at a sewage treatment plant. Millions of years ago, lakes dried up and glaciers compressed their sediment. In this sedimentary rock, fossils are found, giving us clues about prehistoric life.

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