Boiling Water with Ice

Purpose:

    You will be able to boil water with an ice cube as a result of the gas laws. Having a glass container with almost boiling water in it's base you will reduce pressure of the water vapor and gas by using the ice cube on the top of the container. The reduced pressure will cause the liquid to boil. Try to relate this to cooking and boiling water at high altitudes.

Materials:

  • One liter Florence flask with stopper

  • heat source

  • hot pad

  • ring stand with ring

  • ice cubes

Procedure:

  1. Fill the flask with 350 to 400 ml of water.

  2. Heat to a boil--remove from heat--stopper immediately.

  3. Let the water cool for about 30 seconds.

  4. Invert the flask and place into the ring of the ring stand.

  5. Rub ice cubes over the bottom of the flask opposite the stopper.

Discussion:

A short time after rubbing the flask with ice you will notice vigorous boiling of the liquid. This was due to cooling the gas which reduces pressure. When the air pressure equals the vapor pressure of the water then boiling occurs.

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