Settling
A pond turns brown after rain. By the next morning, the water on top looks clear.
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Step 1 of 4
- Muddy water, freshly stirred. Mud is everywhere.
- Left still. The heavy mud starts to sink.
- Mud rests at the bottom. Clear water sits on top.
- Tip carefully. The clear water pours off.
The rule
Sedimentation — heavy bits sinking to the bottom when left still.
Decantation — pouring off the clear water on top, slowly.
Only solids that do not dissolve can settle.
Salt in water is dissolved: you cannot see it. Its tiny pieces do not sink.