Now I'm curious-- I wonder if there is a way to mitigate the effects of the loud noises? With the summer holidays coming up, we'll have fireworks going off all over the place, esp. for those of us in states where they're legal to have at home (and anyway, who wants to miss those? ;) )

For instance, when I was around/did historic interpretation, they'd always warn you never, ever to plug your ears with your fingers around a cannon because the pressure changes with the addition of a seal can rupture your eardrums. You cup your hands over your ears instead.

Anybody know about the physics and what it does internally?

There is a big difference between a cannon blast that puts out huge pressure waves and fireworks that put out less powerful pressure waves. Foam ear plugs work good to reduce the noise.

Many of us don't get involved with or near fireworks, much less firecrackers. There are no high powered firecrackers legal in any state. M-80's, M-100's, Silver Salutes, and others like them are considered explosive devices and outlawed for use by unlicensed personnel. In some states, they can be sold and possessed but not discharged.

Good common sense goes a long way with sounds and especially fireworks.

Any non-directed pressure wave weakens at the square of the distance from the sound.

Pressure waves and sound intensity are different things.

Decibels drop by 6 dB's for every doubling of the distance from the sound source. A sound of 150 dB's at 1 meter drops to 144 dB's at 2 meters. At 4 meters, it is 138 dB's. At 8 meters, it is 132 dB's.

One of the most important considerations for those of us who have suffered a concussion is to not aggravate specific symptoms. If you are sound sensitive, please try to moderate your exposure to sound. Young ears are far more sensitive to sound that old ears with ear drums that are stiffening from years of excessive sound.

The excitement from loud sounds is a adrenaline response that is also not good for a recovering brain. This adrenaline response is biologically intended to spark fear and caution so the person removes themselves from the dangerous environment. Over-riding that response DOES DAMAGE to the person.

Be careful and use common sense. Your ears and brain will thank you.

btw, A sound pressure wave is like a water wave except air is compressible. There is the peak pressure that is followed by a low pressure. The high and low are both equidistant from the normal. Plugging the ears with a finger tip seal makes it so the inner ear is subjected to the high then low pressure. The seal keeps the outer pressure at normal. So, the ear drum get the ride on the top of the wave to the bottom of the wave.

Think of the pain some suffer in airplanes as they ascend and descend. This is just a very very slow version of sound pressure differentials. The popping during ascent is air escaping the eustachian tubes to the back of the throat. This popping often happens during a yawn or other jaw movement that causes the eustachian tubes to break their seal. This seal does not break as well during descent, especially for those with active hay fever allergies so pressure builds painfully until the seal breaks or the ear drum ruptures. Low pressure behind the ear drum causes the ear drum to be stretched causing pain until air leaks in through the eustachian tubes.

With the ears cupped or protected with foam ear plugs, the pressure wave effects both sides of the ear drum at the same time. There is no or minimal pressure differential between the inside and the outside, especially if the mouth is closed or turned away from the sound source.

Have someone hold a sheet of paper vertically in the air. Clap your hands so they both hit the paper at the same time. The paper does not move. Each hand signifies the high part of the pressure wave. They effect both sides of the paper (ear drum) simultaneously and equally.

Now, hold one hand 6 inches from the paper and clap the other hand at the stationary hand through the paper. The paper is violently moved toward the stationary hand. That is similar to just the high part of the sound pressure wave. The stationary hand is like the finger plugging the ear. The moving hand is like the high part of the sound wave as it pushes the paper (ear drum) toward the stationary hand.

If you pulled the moving hand back as fast as possible, it would whip the paper away from the stationary hand similar to how the low side of the pressure wave created a sort of vacuum momentarily. If this effect the ear drum, the violent movement can tear the ear drum. This is very painful.

To paraphrase xkcd,

STAND BACK! He's going to try SCIENCE! :D

thanks for the explanation! super interesting :)

You asked about the physics of the loud bang. I did not even add the part about a cannon. A cannon pressure wave is more linear as it shoots out and away. The projectile often goes supersonic which results in a supersonic pressure wave (the sonic boom). This has even more energy in it.