TOPIC:

ID Code: I4-32
Purpose: Freeze water by reducing the ambient pressure.
Description: Place about four drops of water onto a cellophane "watchglass" in the vacuum chamber as in the photograph at the left. Evacuate the chamber with the vacuum pump. Almost immediately the water will begin to bubble (boil), as seen in the middle photograph below, and within about one minute the boiling will subside and the water will freeze. When the water freezes it is clearly seen to become opaque on the overhead projector screen, as seen in the photograph on the right below. This is a very dramatic demonstration.
Availability: Available