We have all seen the videos of astronauts playing with water in the International Space Station. Water moves in curious ways and seems to be causing a lot of interest from general public. However, why water behaves the way it does and how to explain its behaviour scientifically is actually quite troubling. Now scientists from the University of Toronto have tackled this question.
Water should, by default, move around to form a droplet mid-air as there is no gravity in space. But what if we add a glass into the equation? There are a lot of factors involved in this question, which makes water in space pretty much unpredictable in mathematic ways. However, engineers are about to test it in an experiment, which is travelling to International Space Station in a SpaceX CRS-9, successfully launched on July 18. Experiment only includes glass jar of purified water, but it is very interesting regardless.
Not only interesting, but very important as well. Water is a crucial element for living and working in space. For example, back in 2013 there was a big problem when water coated the face and helmet of Italian astronaut Luca Parmitano during a spacewalk. Predicting water behaviour in glass containers can be done on Earth – Charles Ward, one of the authors of the study, predicted that in short cylindrical containers water will stick to the walls leaving a spherical bubble of vapour in the middle and in longer ones water will tend to pool at both ends of the container leaving a gap of vapour in the middle. The later he called “a “double-interface configuration.” But he could not prove his predictions and space experiments were needed.
Back in 1997 Ward did send his experiment (jars half-filled with water and air pumped out), but results were not conclusive because of poor resolution pictures. A new PhD student got interested in the experiment in 2008 as the new equipment would allow better results. Scientists created a better model and attached a GoPro camera to capture high-resolution images and video.
Scientists say that results can be useful for us on Earth too. Aaron Persad, one of the authors of the experiment, said: “These days, there is growing interest in nanofluidics, which is all about understanding the behaviour of liquids in channels 10,000 times thinner than a strand of human hair. At such tiny scales, the effect of gravity is minimal, so the liquids behave similarly to what we see in space”.
It is still not entirely certain if experiment will work well. But if it does, it will finally put an end to the debates lasting for almost 20 years.