Why Do We wash dishes with soap?

Ever wonder why we use soap to wash dishes? In short, it’s to break down fat aka dirt that is usually in the dishes that got there when you served us omena last time we came to your place.

Try out this simple experiment at home and let us know what you get. Preferably with a video.

For this activity, you need…

  • Food coloring (blue,red and yellow),
  • 1/2 cup room temp milk,
  • 1/4 cup dish washing detergent,
  • 1tbs salt.
  • 3 plastic pipettes(or straws) (label: “blue”,”red”,”yellow”).
  • 2 plastic spoons(label: “glue”,”salt”).
  • 4 plastic 50ml short-glass (label: “blue”,”red”,”yellow”,”salt”).
  • 2 plastic glasses (label:”milk”,”glue”).
  1. Pour milk in a cup.
  2. Using pipette, add drops of food colouring in a triangle or square pattern.
  3. Using pipette add a drop of soap in the middle of the food colouring design watch the colours move.
  4. Now,instead of using milk, repeat steps #1-3 with white glue.

Milk has many ingredients including fats. The soap detergent breaks down these fats and the food colour helps show this action taking place.

This is why we need to wash dishes with soap. Soap removes stains like fats which are difficult to remove with just plain water.

  • What happens if you add salt?
  • Does the size of the cup matter?

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