Since the beginning of the manned space program, astronauts have been playing with water in microgravity conditions. The result has been a large assortment of videos demonstrating the unique and amusing properties of water.
In the first video on this page, Chris Hadfield, an astronaut with the Canadian Space Agency demonstrates what happens aboard the International Space Station when you ring out a soaked wash cloth in the weightlessness of space.
The experiment was suggested by students Kendra Lemke and Meredith Faulkner of Lockview High School in Fall River, Nova Scotia. It was posted on YouTube in 2013.
The video shows that the surface tension of water is great enough that the water keeps clinging when Hadfield rings out the cloth. If you watch closely, however, you can see a few droplets fly off when he starts to ring out the cloth.
In the second video, British astronaut Tim Peake of the UK Space Agency bats around a sphere of water with something like ping pong paddles. In this case, the paddles are made of hydrophobic material, so the water does not cling. He also adds a fizzy tablet, like an Alka-Selzer, to the floating sphere and watches the result.
I think the astronauts are having as much fun with these “experiments” as the kids watching them back home. In this case, there was a video link during a “Cosmic Classroom” event last year at the World Museum in Liverpool. Peake’s full 20-minute presentation — with some wonderfully amusing questions from kids — can be found on YouTube.
Speaking of having fun in a weightless condition, a team of researchers aboard a DC-9 in freefall popped about 50 water balloons during successive trips in the 1990s to see what would happen.
Led by fluid-mechanics engineer Mark Weislogel, these researchers called this science, but I think they were just enjoying themselves — and making a mess while doing it. A little stray water didn’t seem to bother them, compared to the astronauts in space, who try to corral as much of the water as they can. Weislogel talks about many experiments, both simple and complex, in a 2014 PDXtalk sponsored by Portland State University, where he has worked the past 15 years.
Astronauts accustomed to drinking coffee on Earth have complained that it is not the same in space, where one typically drinks with a straw to avoid spills. For one thing, a coffee drinker usually likes to experience the aroma of coffee, which is not the same through a straw. Engineers figured out that a container with a sharp enough angle will cause the coffee to wick up, so it can be sipped from the container, as shown in the video featuring astronaut Don Pettit aboard the ISS in 2002. Later, designer Travis Baldwin created an actual coffee mug for space based on the same design.
Finally, if you ever wondered what boiling water would look like in space, NASA ran a series of experiments from 1992 to 1996. On Earth, convection causes hotter regions of the liquid to rise while cooler, denser regions sink. Once bubbles forms, buoyancy causes the bubbles to rise rapidly to the surface. In a weightless state, the heat spreads in all directions, and bubbles don’t rise but join together to make a bigger bubble.
The actual experiments in space, shown in the last video, used a Freon coolant as the liquid to demonstrate the effects. Freon has a lower boiling point, so less heat is needed to get the same result. The experiment is described in NASA’s Science Beta series.