The Mystery of Impact Flashes - Smarter Every Day 307
Added 2025-03-31 15:24:19 +0000 UTCThank you so much for supporting on Patreon! This was an absolutely awesome rabbit hole to go down. What do you think is going on? I'll be reading the comments here on Patreon (and commenting over the next couple of days). I'll definitely be planning for and updated video on this phenomenon. I'm thinking I need to do this in a vacuum FOR SURE.
Comments
Definitely wanna see this done in a vacuum! My thinking is that it's compressive heating, and it's not "igniting" or anything, just getting to the temperature necessary for blackbody radiation in the visible spectrum. If that's correct, there should be no flash in a vacuum, since there's no gas getting compressed.
Rosuav
2026-03-07 11:35:02 +0000 UTCIs it just me, or are there a crazy number of comments?
Samuel Svendsen
2025-05-19 19:31:47 +0000 UTCA good test of compression vs fracture would be to flood the tank with a gas that is not combustible and use the marbles again. That way you can rule out the gas’s burning and see if the fracture in the marbles is your light source. Also I believe that glass at this speed of impact will behave more like a crystalline solid than a liquid because it will not have the time to deform and will fracture along the silica structure of the glass. I am firmly convinced the yellow flame is the combustible gases being compressed to the point of ignition by the pressure wave in front of your projectile. To test this shoot slower and slower projectiles until the flame is not produced. I don’t know the math but I would see if there is a way to calculate the speed, surface area of the projectile and the density of the gasses to find the compression at point of impact, and use that to calculate the temperature this would produce. Does it hit the flash point for the gasses involved. I keep thinking that this is basically the way diesel engines work just without the cylinder walls using gasses with a higher ignition temp. A last thought is the heat at impact possibly creating a flash of plasma as the materials make contact, sublimating the material at point of impact if the energy involved is high enough.
SqrlLrd
2025-05-13 22:35:46 +0000 UTCSome of the gas in the first of the polycarb shots, appeared to behave like plasma. one even had a jet to the upper right.
AE5EZ
2025-05-08 04:11:04 +0000 UTCHey Dustin I know the odds of you seeing this are slim, But could you ever do a slow mo video and breakdown of welding processes. It is a part of almost every industry in some form or fashion and would be cool for the world to see/understand what is happening.
Nate Hoppes
2025-04-28 05:21:43 +0000 UTCI am watching this video now and came here to make the same comment.
Chad Daulton
2025-04-19 02:36:02 +0000 UTCHave you seen the latest Slow Mo Guys video where they shot panes of glass with 30-06? The flash correlates to velocity. And they caught the reflection on panes of glass behind the pane of impact. If you mimicked their setup, you could shoot a piece of glass that has a mirror behind it. If you set the focus to the mirror you could have a better view of the impact. You’d have to figure out a shooting angle that’s not obscured by the projectile. Would certainly add more data points. Link: https://youtu.be/05-ceCK5e9U?si=p_HUIn6FXjED1K8L
Joe Schneider
2025-04-18 02:54:43 +0000 UTCim not sure if you've seen it but VSauce has a short about 2 metal balls colliding (https://youtube.com/shorts/-hzue8KIS9M?si=rL0Nk3Xkctu-aSAL) this may be a low-energy replica of the same event. but im with you on the belief that this is caused by the gasses between the projectile and the target surface. Keep being awesome!
Robert Lund
2025-04-15 18:26:25 +0000 UTCI got my stickers today and they look awesome Destin! Crossing my fingers that this flash topic could be in the next batch
jahr
2025-04-09 19:51:44 +0000 UTC# Why I think this is happening I also think its the gas igniting from compression. I think the gas pressure goes up near the point of contact because it cannot move out of the way fast enough. # Schlieren photography I really wanna be able to see how the gas is moving around, you could try imaging it with schlieren photography. # Repeat experiment in vacuum method #1 You'll probably need to re-manufacture a box for that to get a good enough seal. Including the shotgun in all that may be complicated, but maybe you can avoid doing that by sealing the bullet entry point with some membrane, similarly to what you did with the supersonic baseball cannon. Except it'll be in reverse now with the bullet entering the low pressure environment not exiting it. # Method #2 Oh or better yet, just replace the shotgun with the same type of system you used for the supersonic baseball and expand the low pressure environment of the barrel to also include the box. # Method #3 Just make a scaled up fire syringe. Either by adding a transparent tube to the end of the shotgun and sealing that shut, or by changing the system to that of the supersonic baseball cannon, but made out of a transparent tube with the end shut closed. This seems a bit dangerous, I don't know how you could avoid the tube from just shattering from either the launch of the projectile or from it stopping. # Experimenting with different projectile shapes I think you might be able to get more consistent results if you machine down the end of the rods to be round. This way the contact surface will always be at 90 degrees and the immediate envorinment of the ignition zone will stay the same as the spheres shape isn't affected by rotation. Additionally you could try just sharpening it like a pencil, or hollowing out a conical cavity in a bid to increase the pressure even more by scooping up air.
Ashley
2025-04-09 19:18:20 +0000 UTC
