APS News

March 2007 (Volume 16, Number 3)

Zero Gravity: The Lighter Side of Science

Water in Zero Gravity

By Sabine Hossenfelder

boiling in space-small bubbles merge into one large bubble
Photos by NASA/Glenn Research Center

Boiling on Earth, boiling in space–small bubbles merge into one large bubble.
In my apartment the heating is in the ceiling. This is not a joke. I’ve wondered where the guy grew up who had this ingenious idea. Had he never heard that hot air rises? But NASA has provided me with a hint regarding this question.

This morning, I was staring at the tea water, waiting for it to boil. Did it ever occur to you that the rising heated water is necessary to get the temperature homogeneously distributed? But what if the hotter water with smaller density does not rise because there’s no gravity? Well, it stays where it is.

Here’s how boiling looks in zero gravity: The heated water stays close to the heater. Regions further away from the heater stay cooler, so the actual heated part boils earlier. Once it begins to boil, the vapor bubbles don’t rise, but join each other due to surface tension. Eventually, one large bubble forms that clings to the heater. Cool, eh? I mean, hot. It looks like this.

(NASA has the full video available at http://science.nasa.gov/headlines/images/boiling/bubble0g.mpg. You can also watch a water balloon burst in outer space here: http://www.space-video.info/misc/balloon.html).

Now I’m convinced the guy who constructed my heating came somewhere from outer space. That’s just how things are up there, why bother. All I have to do is sleep on the ceiling.

Sabine Hossenfelder is a theoretical physicist at the Perimeter Institute. She writes the Backreaction blog (http://backreaction.blogspot.com) with her husband, Stefen Scherer. A full article on boiling water in zero gravity can be found at http://science.nasa.gov/headlines/y2001/ast07sep_2.htm.

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Editor: Alan Chodos
Contributing Editor: Jennifer Ouellette
Staff Writer: Ernie Tretkoff

March 2007 (Volume 16, Number 3)

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Articles in this Issue
"Woodstock of Physics," Quantum Computing Among Highlights of 2007
Meet the New Editor-in-Chief
Poll Finds Significant Interest in School Boards Among Physicists
APS Gathers Postdoc Best Practices; Comments are invited
Built for Speed: NASCAR Physics Featured in Public Lecture
New Report Reviews Primary Economic Driving Factors in U.S
PRL Launches New Feature to Improve Accessibility
Fellows Reign in Southern California
Committee on Informing the Public Holds First Meeting
Getting High on Physics
Members in the Media
This Month in Physics History
Zero Gravity: The Lighter Side of Science
Schrodinger's Parrot
The Back Page
Inside the Beltway: Washington Analysis and Opinion