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How to Chill Water Using Pressure

You can freeze boiling water. The boiling point of water is sensitive to atmospheric pressure; the lower the pressure, the lower the boiling point. The point at which water freezes is not so sensitive; it only changes in extreme conditions. When you gradually remove the atmospheric pressure, water will begin to boil; and then, when the pressure is all but sucked out, the water will instantly freeze. To chill water using pressure, you must first boil it.

Things You'll Need

Plastic foam cup
Water
Vacuum chamber

Instructions

- 1
  Purchase a 1-gallon vacuum chamber. Vacuum chambers are used to suck the air out of resin molds, so you may be able to find one at an art supply store. Ask your local high school where its science department gets its science supplies as bell jar vacuum chambers are often used in the classroom. Make sure the chamber can be taken to full vacuum.
- 2
  Pour water into a plastic foam cup three-quarters of the way. Place inside the vacuum chamber. Seal the vacuum chamber.
- 3
  Start the vacuum pump. Watch as the pressure drops and the water begins to boil.
- 4
  Look for visual signs that the water is chilling and stop the pump. The boil will end abruptly, an ice crust will immediately form and then the water will quickly freeze through. Stop the pump when the water is chilled to satisfaction.
- 5
  Remove the water from the vacuum chamber. This entire process takes seconds.

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