Fireworks Sound level at difference distances

In summary, the recommended safe distance for watching fireworks is a minimum of 500 feet or 150 meters. The sound level of fireworks varies depending on the type and distance, with levels reaching up to 120 decibels at 100 feet and dropping to around 90 decibels at 500 feet. However, fireworks at a distance can still cause hearing damage. They can be heard from several miles away, but the sound level decreases significantly with distance. To protect your hearing, it is recommended to stand at least 500 feet away from the source, wear earplugs or earmuffs, and take breaks in between firework displays.
  • #1
norcal36
8
0
Homework Statement
A firework goes off high above you, a distance d1=500m from your head, and you hear an acoustic pressure of 10Pa. Your sister is a distance d2=4.00x10^3 at the same time. If air absorbs 7.00 db/km in sound energy what sound level does your sister hear? Density of air=1.2kg/m^3....Speed of sound=343m/s.
Relevant Equations
I=pmax^2/2*density*velocity
I=power/Area
10log(I/I0)
This is the work I've done so far...

I=p^2/2dv...I=(10)^2/2(1.2)(343)=.12112

I(A)=P...(.12112)(4pi(500)^2)=380522.366

I=P/A...380522.366/4pi(4000)^2=.0018925

10log(I/I0)...10log(.0018925/10^-12)=92.77db

92.77-7(4)=64.77db

I am winging it and that's the closest I can get to the right answer which is 68.3db...

Any Guidance would be greatly appreciated!
 
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  • #2
The 10 Pa at your place already had 3.5 dB absorption from the air in the first 0.5 km. You only need to consider 3.5 km more, that increases the sound level by 3.5 dB relative to your calculation and produces a perfect match.
 

1. What is the maximum safe distance to watch fireworks in terms of sound level?

The maximum safe distance to watch fireworks in terms of sound level is typically around 500 feet. This distance may vary depending on the type and size of the fireworks being used.

2. How loud are fireworks at different distances?

The loudness of fireworks can vary greatly depending on the type and size of the fireworks, as well as external factors such as wind and surrounding buildings. At a distance of 500 feet, fireworks can reach sound levels of up to 140 decibels, which is equivalent to a jet engine.

3. What factors affect the sound level of fireworks at different distances?

The sound level of fireworks can be affected by a variety of factors, including the type and size of the fireworks, the location and surroundings of the fireworks display, and external factors such as wind and humidity. Fireworks in open areas tend to produce louder sound levels compared to those in more enclosed spaces.

4. How can I protect my hearing when watching fireworks at close distances?

To protect your hearing when watching fireworks at close distances, it is recommended to wear earplugs or earmuffs. These can help reduce the sound level and protect your ears from potential damage. Additionally, limiting the amount of time spent near the fireworks can also help minimize the risk of hearing damage.

5. Are there any regulations for the sound level of fireworks displays?

Yes, there are regulations in place for the sound level of fireworks displays. In the United States, the Occupational Safety and Health Administration (OSHA) sets a maximum permissible exposure limit of 140 decibels for impulsive noise, which includes fireworks. Local governments may also have their own regulations in place for fireworks sound levels, so it is important to check with your city or town before setting off fireworks.

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