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Chapter 3, Lesson 6 Multimedia

Hot Water on Cold Water

This demonstration shows that the density of hot and cold water are sufficiently different that you can layer them on top of one another.

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  • In the hot (yellow) water, the water molecules are slightly further apart than in the cold (blue) water.
  • The hot water is less dense and floats on the cold water.
  • When the cold water is placed on top, it sinks in the hot water.

Cold and Hot Water

This animation shows that the density of water changes with temperature. A graduated cylinder of water is shown to be slightly more or less full depending on the selected temperature range.

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  • The molecules in hot water move faster and are a little further apart. When the water is heated, the level moves up slightly in the graduated cylinder.
  • The molecules in cold water move slower and are a little closer together. When the water is cooled, the level moves down slightly in the graduated cylinder.