Asked by: Cameron Ross, East Kilbride
Down on Earth, when we blow air into a mixture of soapy water, a bubble forms as the growing ‘bag’ of air formed from the soap film moves the surrounding air out of the way. In the vacuum of space, there’s no surrounding air to push back on the outside of the soap film, which is so weak that it would burst pretty much instantly.
Inside a spacecraft, however, it’s perfectly possible to blow bubbles, even in the absence of gravity. They’ll still look like nice, neat spheres, and they’ll float pretty much the same: bubbles in space or on Earth are filled with the same air that surrounds them, so they’ll float regardless of whether there’s gravity or not. Space-based bubbles might stay put a bit longer, though, as the liquid soap in their membranes won’t tend to flow to the bottom, making the top of the bubble thinner and thinner.