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Nature of Matter



Mixing in cold water: Observational Experiment


Try and construct a model of how things mix.

Prior Knowledge

Work though the experiments and reasoning in the cycle Nature of Matter.

Description of the Experiment

A drop of dye is placed in a beaker of cold water. Observe what happens to the dye. The movie is played at seven times normal speed. Carefully note how long it takes for the dye to mix into the water.

Youtube movies can be stepped frame by frame using the , and . keys on your keyboard. If you want to download the movie to your computer, right-click or control-click HERE.


  • Try and construct a model of why the dye mixes into the water. Observations of evaporation may help here.
  • What things are necessary for the dye to be able to mix as it does?
  • What would you expect to happen if you repeated the above experiment, but with hot water? (To make further observations or test your model, view the next video.)