PURPOSE: To demonstrate the force created by freezing water.

DESCRIPTION: A short cast iron nipple with caps on each end is filled with water and dropped into a container of liquid nitrogen. Within about one minute the water freezes, expanding sufficiently to break the cast iron pipe with a loud crack and a big cloud of vapor. Be careful to fill the pipe completely with water before immersing it in liquid nitrogen. If it does not explode, leave it alone; it may still be dangerous.

SUGGESTIONS: We use short pipe nipples because they are much cheaper than the traditional cast iron spheres and they seem to work better. The end caps can be re-used.


EQUIPMENT: Ice bomb nipple with two end caps, liquid nitrogen in styrofoam bucket, gloves, and steel outer bucket with weighted cover.

SETUP TIME: 5 min.

Go back to Lecture-Demonstration Home Page.