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Rocks

Sedimentary Rocks - Definition.

Sedimentary rocks are formed from sediments.
Sediments are small pieces of material which do not dissolve in water.
They slowly fall down to the bottom of a lake or the sea,
and gather together over the years forming a large mass of material.

Imagine stirring very fine sand into a glass of water.
Slowly the sand particles settle on the bottom of the glass.
They are called "sediments" from the Latin sedimentum
meaning "a settling".

Materials which do dissolve (salts), stay in the water.
This is what has made the sea salty over many millions of years.

Where have these sediments come from,
and how do they get into the sea?

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