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Space Station Science

Picture of the Day

April 15, 2003

Blowing Bubbles

Credit: Don Pettit, ISS Expedition 6 Science Officer, NASA

Explanation: Not long ago International Space Station science officer
Don Pettit discovered the amazing properties of watery thin films in
space: They're remarkably tough. You can shake them, spin them, even
paint on them. 

Now he's learned how to blow them up, too.

It's done using Alka SeltzerTM. Don describes the procedure: "Here we
have a liquid film made of very little water stretched across a wire
loop. We simply drop an effervescent tablet into the middle. You can
see that the volume expansion is quite significant as chemicals in
the tablet (baking soda and citric acid) dissolve in water and then
react to form carbon dioxide gas. The resultant bubbles inflate the
film." 

"The fate of bubbles in a liquid is an important topic for operations
in low gravity. Whether you're designing a science experiment or a
piece of engineering equipment that is supposed to work in this
environment, it's really important to understand what happens to gas
in liquid and vice versa. I'm hoping this demonstration will give
[designers] some ideas about what might happen to their systems up
here and maybe inspire some new experiments." 

The full-length video of his demonstration shows how tiny bubbles
swirl (hypnotically) in a stirred film, how small bubbles combine to
form bigger and bigger pockets of gas, and how unwanted bubbles can
be removed from gas-contaminated fluids using a syringe. 

"These thin films really are a wonderful tool for experimentation."
So what's next? "The best is still ahead," he says. Stay tuned.... 

Editor's note: Don Pettit has done similar experiments involving
effervescent tablets and spheres of water (rather than films of
water). See the entire series: Reel 1 (2Mb); Reel 2 (4Mb); Reel 3
(2Mb); Reel 4 (4Mb)
 
Credits & Contacts
Author: Dr. Tony Phillips 
Responsible NASA official: Ron Koczor 
Production Editor: Dr. Tony Phillips 
Curator: Bryan Walls 
Media Relations: Catherine Watson

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