How to Make Frost on a Can

The amount of water vapor the air can hold is determined by changes in the air's temperature. Air holds less water vapor when it is cold. A simple experiment, using a metal can, demonstrates how frost forms when this occurs. Salt, when added to ice, absorbs water. The process of absorption produces heat that melts the ice, lowers the water temperature and chills the can below 32 degrees. When outside air comes in contact with the can and the air temperature drops, water vapor is produced. Because the water vapor is in contact with the can, it freezes, producing frost.

Things You'll Need

• Metal can
• Water
• Salt
• Crushed ice

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Instructions

1. • 1

     Remove the label from a small metal can. An empty soup can will work for this experiment.

   • 2

     Fill the can 1/4 full with water.

   • 3

     Measure 4 tablespoons of salt and add to the water. Stir the water and salt.

   • 4

     Add crushed ice to the water. Fill the can to the top.

   • 5

     Allow the can to sit undisturbed for 2 to 3 minutes. Observe that a layer of frost has formed on the can.