Demonstrating the Separation of Mixtures

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Updated on Dec 09, 2011

Grade Level: 7th to 10th; Type: Chemistry


In this experiment, you will separate large-scale substances to understand how mixtures are made and the variance in the physical properties of their ingredients.

Research Questions:

  • Why does the density of the water change when salt is added?
  • If paper was added to the experiment, how would you change the experiment to separate the paper from the plastics and metal?
  • If glass was added, how would you change the experiment?
  • Is this experiment a good representation of your recycling bin at home?


  • Container
  • Small pieces of heavy plastic jugs
  • Small pieces of light plastic bottles
  • Small pieces of aluminum cans
  • Magnet
  • Net
  • Salt
  • Water

Experimental Procedure

  1. In the container, combine the pieces of plastic and metal.
  2. Use the magnet to separate and pull out the metal materials. Set them aside.
  3. Fill the container with water.
  4. Gradually add salt to the water until one set of plastic pieces begins to float.
  5. Use the net to retrieve the floating pieces. Set them aside.
  6. Use the net to remove the remaining pieces. Set them aside.

Terms/Concepts: Solubility, Magnetic Properties, Mass



Magnetic Properties: