Astronaut Don Pettit narrates some of his experiments with air and water droplets in microgravity in this video. The lack of body forces and buoyancy in microgravity means that surface tension effects frequently dominate. Pettit’s demonstrations also involve some fun basic physics with bubble behaviors inside of water droplets. See more of Pettit’s Saturday Morning Science videos for additional microgravity fluid mechanics.
Tag: microgravity

Mentos & Diet Coke in Microgravity
For a little Friday fun, consider this microgravity experiment conducted aboard the infamous Vomit Comet: what happens when you combine Diet Coke and Mentos in microgravity? For the record, I think this is the answer. (Via jshoer, who will be flying on the Vomit Comet in 2 weeks – but sadly not with a fluids experiment)
Microgravity Boiling
Boiling a liquid is a common enough phenomenon that we are all familiar with it. But, as with many aspects of fluid mechanics, removing gravity drastically changes the situation.

Combustion in Microgravity
‘Hot air rises.’ It’s common knowledge. But we usually forget that this is only true thanks to Earth’s gravity. On Earth, a candle flame’s distinctive pointed shape is due to hot air rising. Without gravity, there is no buoyant convection; hot air has no reason to rise (and no definition of what up is either!). This makes flames in microgravity spherical, as in the video above from a drop tower on earth. See also: astronaut explains fire in microgravity.

Drinking Coffee in Space
Operating in microgravity disrupts a lot of everyday routines. However, astronauts have learned to take advantage of surface tension to enable them to drink their daily coffee from a cup still.

Water Balloons in Microgravity
Sometimes you need microgravity in order to observe the neat effects of surface tension on a fluid. Also, I hear it’s a good excuse for popping water balloons on the Vomit Comet. #
