Wringing out Water on the ISS - for Science!

What people said

Recommends ulidtko · 2013-10 · Space Exploration Stack Exchange · on “How would one go about proving humans have really been to outer space?”

Yes, humans definitely have been to outer space. The easiest proof I can think of immediately is this video [this video] of commander Chris Hadfield [LINK] demonstrating wringing of a wet towel on the ISS [LINK] . Or this one [LINK] — it contains more than 200 seconds long uncut shot of a̶b̶s̶e̶n̶t̶ micro -gravity. It also shows vast interiors of the ISS, which are technically challenging to simulate in a "vomit comet", due to theirs volume and structure. Update: it isn't impossible [LINK] to see astronauts spacewalking near the ISS from the ground, given enough time, skill, and equipment. It has been done before. However, you can still claim that the photographs could've been edited and/or made

Recommends John Rennie · 2013-12 · Physics Stack Exchange · on “Container of liquid in free fall”

The incomparable Chris Hadfield did a related experiment [this video] on the ISS using water on a cloth. You can see that the water does not fly off the cloth. To simplify the experiment consider water on a flat surface: The air/water interface has an energy per unit area, so increasing the area of the air/water interface takes energy. This is also true for the water/substrate interface, and the question is which interface has the higher energy. If the air/water surface energy is greater than the water/substrate surface energy then the drop tends to spread out, as shown on the left, and the water sticks to the surface even in zero-g. If the water/substrate surface energy is greater than the air/w

Recommends TildalWave · 2014-01 · Space Exploration Stack Exchange · on “How does plant growing medium not scatter around?”

Generally, without any external disturbance, cohesive forces of the materials in use will be sufficient to keep them together, since they all share the same inertial frame. But sure, to prevent soils from scattering around when moved around, worked with or perhaps due to air circulation, they can be contained in growing pots or similar containers that would additionally hold the soil due to surface tension. Canadian astronaut Bob Thirsk holds plants while on board the ISSn in 2009. (Credit: Canadian Space Agency) Adding water will only increase this cohesion because of increase in surface tension it would provide to the growth medium. So in general, there's no need to additionally "secure" t

Recommends Floris · 2015-06 · Physics Stack Exchange · on “What happens to the air in a water bottle when it falls?”

If you drop a bottle without any residual motion (that is, it is not spinning etc) then everything inside that bottle will be in "free fall". The air and the water will attempt to fall at the same rate. There is a nice video of what happens to water when it "spills" in the International Space Station [this video] : it becomes a "blob" because of the surface tension. Add to that a small amount of attraction between the liquid and the bottle it is in (hydrophilic surface - attracting rather than repelling water) and you see that the water will actively want to stay in the bottom of the bottle: there is no force to move it away, and there is actually a (weak) force keeping it there. So the air stays

Cites L.Dutch · 2017-08 · Worldbuilding Stack Exchange · on “What if gravity goes out while man is swimming in a pool on board of a spaceship?”

Removing gravity will remove the buoyancy on the poor swimmer. The surface tension of water will make it flow all around him/her and also inside his/her nose and lungs. Basically the swimmer will be sucked into the mass of water by the surface tension, and according to his/her apnea skills he/she can survive up to few minutes before drowning if he/she doesn't manage to reach a solid grip and exit the bubble. Moving inside a bubble is doable (basically it is just underwater swimming), the issue is breaking the water film to get out of it, as there will be no gravity assisting the effort (insect drinking from water droplets have to hold firmly on a surface to not be sucked into the droplet, sa

Cites Giter · 2018-02 · Worldbuilding Stack Exchange · on “What would it feel like if the entire Earth could fit into the palm of your hand?”

There are really two options for what this would be like, depending on whether physics has mostly been thrown out the window or not: Pretty much ignoring all the non-fun physics: According to this Skeptics StackExchange [LINK] , the earth is as smooth as pretty fine sandpaper, so it would 'feel' like holding a rough, mostly wet ball of rock. Since you're more massive than the Earth, and thus have more gravity, the atmosphere and all the water would quickly leave the Earth and slosh around on the surface of your hands [this video] . Obviously, this would be bad for the Earth because people like having air and water. Earth is moving fast around the sun, but if you're already moving fast enough to h

Cites Tristan · 2019-09 · Space Exploration Stack Exchange · on “Can/should you swim in zero G?”

Off the top of my head, two issues for free swimming (no breathing gear) I can think of: Absent a sense of "up" and "down", it would be very easy to become disoriented and lose track of where the nearest surface is to take a breath. Surface tension will become the dominant force governing water flow as you come up for breath. In particular, the water will cling to your face [this video] , making getting a clear path to breathe difficult.

Cites Eliza Wilson · 2020-06 · Space Exploration Stack Exchange · on “Why might an astronaut wear their wristwatch very loosely aboard the ISS?”

In this video [this video] of CSA Astronaut Chris Hadfield aboard the ISS, he wears his watch very loosely--so that it continually bumps against different sides of his arm. I imagine this might be mildly irritating or get in the way of precise work, although it is possible he simply does not mind. From looking at pictures, it seems like Hadfield often wears his watch this way, and I have not yet found any evidence of another astronaut wearing a watch loosely. This makes me curious--why might an astronaut wear a wristwatch so loose? Are there aspects of an astronaut's work, zero-g, or the ISS that might explain this--perhaps something to do with concerns of constricting blood flow in microgravity?

Cites n2qzshce · 2022-04 · Worldbuilding Stack Exchange · on “The immediate and long term effects of slashing wounds in microgravity”

So, this is a bit of postulation based on what we know from the real world... First off, despite a certain television program's insistence that gravity is part of the healing process, the effects still happen in an environment where you're neutrally buoyant, e.g. weightless. If you're swimming, a cut will still clot, even though you are neutrally buoyant. Gravity is not a trigger for clotting factors or healing in general. As to what happens to the blood you bleed, blood is considered a Newtonian fluid, so I imagine it'd behave quite like water [this video] . Thank you Chris hadfield for your [water experiments].( [LINK] )

Cites uhoh · 2023-10 · Physics Stack Exchange · on “How would the volume of a drop of water (from a dropper) on the Moon and other bodies compare to one on Earth? (indoors of course!)”

Searching for "volume of a drop of water from an eyedropper", I ran across this answer on Quora [LINK] : It depends on the size of the dispensing tip, but generally for a Pasteur pipette it is about 1/20'th of a mL. That is on Earth, at or near sea level. (Incidentally, other values from other sources put it at 1/17 or 1/18 mL. It will probably be somewhat dependent on the shape of the dropper tip and material.) Assuming we are "indoors" at standard temperature and pressure, how would the volume of a drop of water vary with surface gravity? Limits : Experiments in space suggest that in microgravity water will likely remain stuck and creep up your arm, so if you call that a drop, the volume c