You can get nearly pure helium from welding supply companies, that's what I did when I was running balloon launch glider competitions. However, it comes in big tanks that might be tough to take to nationals. I bet a couple teams might have some and may share if you ask nicely. Otherwise, you might be able to find one in Madison if you are willing to get one there.Hmm, a custom mylar balloon the size of a Mission Possible would be quite heavy. My partner weighed a deflated standard 2 sheet 18 inch mylar balloon and told me it weighed about 50 grams. I wonder if it is possible to get more concentrated helium. I'm sure that the average helium tank is not pure helium, I wonder how much of the gas is actually helium and if it would be possible to somehow purify it further.
Even if the height of the device were minimized, wouldn't the top of the balloon be considered the top of the device? So the balloon would have to lift the sign past where its original top was... or am I wrong about thatMy guess is they have an insanely large balloon; one that takes up half or more of the device, maybe custom made. Then, if the competition is in a gym or some place with a really high ceiling, they use the momentum of the balloon itself to pull up the weight. To do this, you just need a really long string between your balloon and the sign (weight). As the balloon rises, it will gain momentum. Once the string runs out, it yanks the sign over the top of the device. Keep in mind, there is not a requirement saying the sign must remain above the device. Another way to get more weight up is to minimize the height of the device, which in turn minimizes the distance the weight has to travel.
We have done tests with the momentum idea, and it seems that there's an optimal length of string that varies depending on the size and shape of the balloon.Yup after seeing what Solon can do round balloons simply won't cut it. Also a side not the momentum idea does not work very well. Perhaps i works for lifting the mass an extra 5 inches but not 50 cm.
My guess is he displaced about 177 grams of air with the balloon;)So you've been able to lift 177 grams?
If so can you describe how you did it?
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