I was thinking about how fire guns are very loud and how its worst in close environments (I had never shot a gun cuz im not american) and I remembered the Mirror room scene in John Wick Chapter 2.
I was thinking if by shooting once, many mirror could break because of the sounds of a gun alone. Has someone tried this or see it happen?
You would need a cannon or higher caliber. It’s easy to break glass at certain frequencies - opera singers can do it.
A sustained frequency can do it, but I’m not sure if a gunshot could be harmonic or if they just have 1 main pressure wave (and mostly just noise elsewhere)
I wonder if the discharge of a regular firearm would shatter movie glass — it’s essentially sheets of sugar, designed to crumble easily without sharp edges. Doesn’t take much force to break it and it’s not as flexible as real glass.
Certainly if you use a big enough gun.
With a pistol or normal gun, probably nothing will happen.
With an anti material rifle you might get some luck if you are close enough.
Or you just take a tank cannon or artillery, those should have plenty of muzzle blast.
Sound waves are energy traveling through the air. Energy is what causes stress, strain and failure in materials. Yes, a loud gun, especially at the right frequency, could break things with a relatively low failure point.
Explosions frequently break glass and a gunshot is basically a small, controlled explosion.
Small being the operative word. Gunshot explosions don’t have enough energy to break glass in most circumstances.
Harmonic frequencies bro its all in the vibes
I think you are assuming a lot of things here. Modern guns and modern glass, for instance.
It’s possible but not likely or common. Glass is stronger than most people give it credit for. Most “hollywood” glass is actually panes of sugar. You could certainly arrange things so that the gun’s pressure wave has a good chance of stressing and breaking glass, but it would take special preparations and effort and the gun would probably have to be very close to the glass. It’s almost unheard of for it to happen normally unless you specifically shoot at the glass.
Someone like mythbusters could probably test this pretty effectively, but based on my experience around guns and glass, I suspect they’d come to the same conclusion.
A not directly related but still interesting video was done by the slowmo guys on youtube
I’m a former Firearms instructor not a physicist. My personal assumption would be you would probably need the blast pressure from the round going off to make direct contact with glass before it lost momentum. I think it would also be dependent on the caliber of the round to generate that level of pressure because something like a 22 long rifle would not be sufficient where something like a 9 millimeter close enough to the material would be and a 50 cal might be 6 feet away. I do not think the Sonic/decibel level force would be enough to damage the material. Sort of like how you can break a wine glass with the right frequency of sound but you can blast it with really really loud sound and it does nothing until it has harmonic vibration. I think it being hit with the concussive force of the expanding gasses or pressure wave, not the decibel , would be needed for that outcome.
Yeah. But the frequency of the sound has to match the resonance of the glass. Any sound can break any glass if they resonate strongly enough to make the glass vibrate violently enough to break. This is pretty hard to do, even when you can control the acoustics of the sound being using to shatter the glass (IE when a singer breaks a wine glass). Finding the right gun and right glass to make it work would be like finding a needle in a haystack.
Using a large enough gun that creates a sonic boom I’m not sure counts. It’s not the sound itself that is breaking the glass at that point, but the concussive force of the wave traveling at high speed.
Basically every modern cartridge is supersonic unless they’re specifically underpowered to make them subsonic.
The smallest thing you’re going to regularly encounter is .22 LR- for context this is the kind of thing you’d use to hunt very small animals- and even that straddles the line of super/subsonic.
Basically what I’m getting at is that it doesn’t need a “large gun”.
Guns would break glass by essentially turning air into a hammer rather than resonance. Also lots of rifles are capable of firing bullets that make sonic booms, it’s just not that powerful when it’s a tiny bullet.
