Perfect Muzzle Flash Photos - Smarter Every Day 43

Hey, it's me Destin. Welcome back to Smarter Every Day.

So, ah, first things first, let me show you that this weapon is unloaded. And I really like to think about firearms because there's a lot of science involved here. What causes muzzle flash?

Alright, number one. We have powder inside the cartridge that's burning; that gas is expanding. It has to overcome the bullet to barrel friction here, in the barrel, and it has to accelerate the mass of the bullet while pushing out the column of air that was inside the barrel. There's a lot of science there.

So, muzzle flash is affected by the cartridge load and the barrel length if you think about it. Another thing that comes into play for muzzle flash is the geometry of the exit. Now, this is just a plain right circular cylinder, so you get a toroidal vortex, but if you think about something like this, you've got a fluted exit here at the muzzle you'll get more of a starburst pattern.

Over the past year, I've been playing around, and I have perfected, I think, a way of taking muzzle flash photos. It involves this, which is a piezoelectric transducer mounted to a wooden box, and I use that to convert acoustic energy to an electrical pulse, which I then send through a pulse generator. And if you don't know what this is, I'll leave a link in the video description here.

So, I then take that output pulse from the pulse generator to create a flash and take a high-speed photo. Now, why would I want to do that, you ask? Answer? Because it's awesome. I mean, look at that.

But after a while, it gets kind of strange taking experimental photos of yourself with firearms all the time, so I invited some friends down to Alabama that you might recognize to take photos with me.

OK, OK, I changed it, and we're gonna see the kick instead of the muzzle flash. I delayed my flash. Alright, you ready to kill the lights, Buzz?

-Yessir.

Alright, hold on. Just, just so I know, what do you think you're gonna look like?

-American hero.

Alright. Kill lights. Ready for the count?

-Ready.

5... 4... 3... [gunshot]

-Well? Let's see.

-From my end that looked good. [laughs] Yep, it looked real good over here.

-No, I'm serious. It was like it was a flash of like, American pride.

Let's put this on your website.

-They're gonna sell posters of this.

-Oh my goodness.

-Oh... oh... That's not what I was expecting. [laughs]

-You afraid of the dark? I'm goin' with your camera, dude.

-There's like two of you. You're like you're ah -What's going on there?

-You can put it on your website. That's all that matters, man.

-That camera's broke, dude. You should take that into the shop.

OK, now we're gonna do the same thing, only instead of a revolver or pistol, we're gonna use a .50 cal?

-.50 caliber. Yep.

So this is Michael from Vsauce, and this is a Safety Harbor .50 cal. It's not the Beowulf round, it's the BMG round, so we've got an AR-15 lower, Safety Harbor upper, and a whole lot of awesome.

Arm?

-Armed.

Alright. 3... 2... 1... [gunshot]

-Did you see the flash go?

Flash went.

-Nice. Nice. So, uh, that's a little bit of muzzle flash. I mean, it's not like an amazing amount. You know, I mean, that's probably less than you're used to.

-We could do better, I think we could do better.

-Well, look at that. Look what the flash did. It made that smoke cloud more opaque. On the bottom right of the quantum composer, hit the blue button.

-Blinking.

Alright. Come back over here and I'll put the round in the barrel.

-Ready?

Yep.

-Alright.

And 3... 2... 1... [gunshot]

Awesome.

-Wow. This is kind of like a man test, if you can do this with your eyes open.

-Look how open your eyes are.

Well yeah, I mean, come on. [laughs]

So there's a handful of you out there thinking, well why don't you just take the output from the piezo and run it through a MOSFET or something like that? You can vary the threshold on that MOSFET and then send a trigger to your flash. Why don't you do that, Destin?

Answer, because I like taking pictures of the bullet itself. That's why. This thing has a really, really fine temporal resolution. It's like 25 picoseconds.

So another thing you might deal with is bullet blur. Bullet blur is calculated by the velocity of the bullet as it exits the weapon, multiplied times the flash duration.

Now, there's two ways to decrease the bullet blur. The first way is a faster flash, and the second way is to turn the weapon more acutely so that you're only dealing with the cosine of that bullet velocity rather than the full bullet velocity.

Now, that's cool, but there's something you have to do if you do that. You have to use a remote trigger, because one of the major rules of gun safety is never be downrange of a weapon. So make sure you do that. Use common sense any time you do experimentation like this.

So there you are, now you're trained on how to take really cool muzzle flash photos. Do not do this if you and everyone around you is not heavily trained in weapons safety. Even if you are trained, just keep in mind, accidents do happen, so use common sense.

That is amazing; I didn't think we could do that. I did not think this would stop the bullet, but it did.

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[Captions by Andrew Jackson] Captioning in different languages welcome. Please contact Destin if you can help.