Daily Curiosities: Bubbles That Don’t Float
POSTED by: on 09/30/2009
Microgravity (aka weightlessness), it is a condition that causes all sorts of interesting phenomena…like bubbles that sit in water without floating.
The reason that bubbles float on earth has to do with the relative density of water compared to air. At sea level, water is 784 times denser than air and so gravity pulls it down towards the earth more than it does air, thus the air rises out of the water. Perhaps a more accurate way to see it would be to say that the water sinks. In microgravity, such as being on the space shuttle in orbit, there is no gravity to pull harder on the water than on the air, so the air has no reason to rise and ends up staying in the middle of the water. NASA has put together some very interesting videos on the behavior of water and bubbles in space. See them here.
Difference in density also explains why steel sinks but wood floats. For information on why steel boats float instead of sink, see Bouyancy.
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