What happens when a NERF dart breaks the SPEED OF SOUND?
The first 1,000 people to click will get 2 months of Skillshare Premium free: http://skl.sh/backyardscientist Keep Reading below!Backyard Scientist merch!! https://thebackyardscient.ist/shop/Thanks iX Cameras http://www.ix-cameras.com/ and Matt Rece https://www.youtube.com/user/mattrece/videos for helping with the high speed shots!Giaco Whatever video: https://www.youtube.com/watch?v=BrtBc-9pQv4A few more thoughts on the Nerf Cannon.Yes, I know if I used a longer barrel I could get higher speeds, but I did not want to deal with a 20ft long gun. I think a 6ft barrel was enough to show what a supersonic nerf dart can do. Davekni got a pingpong ball going 2000mph which is 2930 ft/s!! (mach 2.5). His barrel was 20ft long. It can shoot through 3/4in plywood! You can see that video here- https://www.youtube.com/watch?v=5xuwu4gjNbQI always thought the speed of sound was the limiting factor, because the flow 'chokes' at mach 1. Its a big controversy among air-gunners, and theres like a 900 post topic on it here https://www.gatewaytoairguns.org/GTA/index.php?topic=102604.540. Some guy got one going like 2100 ft/s which I thought was impossible. https://www.youtube.com/watch?v=qUq4OQqZ2bw So it prompted me to do some research.It turns out flow does choke at mach 1, but its only the mass flow that chokes. The gas can still expand supersonically.Also a big thanks to Dr. Carl Knowlen from University of Washington, and u/Overunderrated, u/TheQueq, and u/InductorMan from reddit.Here are the papers I referenced:A COMPARISON OF DISTRIBUTED INJECTIONHYPERVELOCITY ACCELERATORS - https://www.researchgate.net/publication/268456817_A_comparison_of_distributed_injection_hypervelocity_accelerators Probably the most concise and easily understood!Numerical Evaluation of a Light-Gas Gun Facility for Impact Testhttps://www.researchgate.net/publication/270629342_Numerical_Evaluation_of_a_Light-Gas_Gun_Facility_for_Impact_TestShows different muzzle velocities for different barrel lengthsTHE THEORY OF HIGH SPEED GUNShttp://www.dtic.mil/dtic/tr/fulltext/u2/475660.pdfProbably the most extensive on the subject "The reader Is assumed to be an advanced student in engineering." I hope you payed better attention in physics that I did.Outro music by MDK, https://www.youtube.com/watch?v=2_t5Lm040GwFortnite clip from https://www.reddit.com/r/FortNiteBR/comments/8e7vq6/the_fortnite_foodchain/