Testing myths about gas inside tennis balls.
Note: I should have added that all of the gases tested would have the same bounce height in a perfect no-loss system. The reason that SF6 bounces higher is because it heats less during compression, lowering the amount of possible thermal loss. Argon heats more during compression, and can lose more energy because of thermal transfer from the gas into the cylinder walls, where it is not restored upon decompression. Things are more complex in a tennis ball, though: Most of the losses are in the rubber shell, and not in the thermal dissipation of the fill gas. It's hard to estimate, but I'd say that the highest fill pressure, with a high-gamma gas would prove to be the most bouncy since it would cause the rubber shell to deform the least. The amount of compression in a tennis ball is very low, and any effect due to the gamma of the gas will be extremely small. Fill pressure will have a dramatically bigger effect.
Google drive link : https://drive.google.com/open?id=10gktbl7YQve5IKNAak1L0wIS_g_4BVEW
Nike Air: https://news.nike.com/news/nike-air-max-sustainability
EPA SF6 use: https://www.epa.gov/sites/production/files/2016-02/documents/conf00_smythe_paper.pdf
100 kg load cell: https://www.amazon.com/gp/product/B077YHNNCP/
Instrumentation amplifier: https://www.ebay.com/itm/INA114-Instrumentation-Amplifier-Module-1000-Times-Gain-Adjustable-Single-Supply/272973857983
SF6 on eBay: https://www.ebay.com/itm/Sulfur-Hexafluoride-SF6-18-lb-Tank-New-full-cylinder-Insulating-Gas-SALE/283464688564
Tennis ball patent: https://patents.google.com/patent/US4358111
SF6 data sheet: https://npeinc.com/manuals/General%20Electric/GEBK-IBvendor/ALLIED%20CHEMICAL.PDF
SF6 worldwide usage: https://www.ipcc-nggip.iges.or.jp/public/gp/bgp/3_5_SF6_Electrical_Equipment_Other_Uses.pdf
General adiabatic resources:
http://rogercortesi.com/ideas/public/gasspring.html
https://arxiv.org/pdf/1708.01282.pdf
http://isjos.org/JoP/vol1/Papers/JoPv1i1-2Tennis.pdf
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/souspe3.html
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