What would happen if an astronaut on a space walk had an empty rubber ballon and filled it with air? Would it just take less air to fill or would it pop with just adding the slightest amount of air?
In: Planetary Science
There is a right amount of air for that situation, but it is much less than on earth.
When a balloon is filled on earth, the air inside the balloon is equal to the elastic force of the rubber squeezing the air inside, plus the atmospheric pressure, which is 14.7 pounds per square inch at sea level, in freedom units.
This means that at sea level, the pressure inside the balloon is greater than 14.7psi by the amount of pressure provided by the balloon’s elasticity.
The pressure exerted by the balloon’s rubber will increase with the size the balloon. Like an elastic band, it takes more force to stretch it a lot than to stretch it only a little. Eventually the balloon and the elastic will break if stretched too far.
If, at the desired/correct size, the balloon’s rubber exerts 3 psi inward, then the inner pressure would be 14.7+3=17.7psi on earth, but in a vacuum only 3 psi would be required to achieve the same size.
Note: when measuring air pressure, for say bicycle or car tires, we are actually measuring the difference in pressure between outside and inside. A car tire at 30psi contains the same amount of air as 47.7psi when compared with vacuum.
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