Experiment with Gases Sheds Doubt on Common AssumptionIf helium is less dense than air, then it would be assumed that with a lesser “weight”, a rubber ball filled with helium to a certain pressure would weigh less than a rubber falled filled to the same pressure with regular air. One could go a step further, based on that hypothesis, and assume that a ball of less weight (the one filled in this case with helium) would bounce higher than the ball filled with air.
To accurately conduct an experiment on these hypotheses, a system would need to be engineered to eliminate the biased variables of inconsistent human motion. So, the two balls are placed at the top of a device with a pull release. No complex mathematical equations or principles of physics are required to calculate the observed results, only a measuring tape behind the balls and a camera to record and slow down the return bounce heights to visible frames.
For more variables, more identical balls were filled to the same PSI (pounds per square inch) but with other noble gases. Xenon and Argon are the prime choices due to their stable nature and lack of propensity to combust. When all of the balls were dropped, bounces recorded and the tests were performed again, the gas content actually factored in nearly not at all! Perhaps because performed on too small of a scale with the ratio of the initial weight of the balls overwhelming any possible influence a change in gas content would have is the reason no observable differences were manifest in the rebounding heights of the balls.
To replicate the experiment with a fairer constant and more accuracy, rubber balls of thinner design and bigger sizes would be necessary. The balls in the initial experiment were about two decimeters in diameter, and at least 6 cm thick. The wall thickness made for such a large weight that the small volume of gas in the space could not compensate to show any difference.