Sound Intensity and Bird Watching

In summary, the conversation discusses a problem where a bird watcher wants to know how far she can be from a bird and still hear its sound. The equation used is I2/I1 = (r1/r2)^2, where I1 is the initial intensity of sound, r1 is the initial distance, I2 is the new intensity of sound, and r2 is the new distance. The correct answer is 1024.34 meters, after correcting a mistake in the value of the threshold of hearing.
  • #1
majormaaz
62
1

Homework Statement


A bird watcher is hoping to add a particular song bird to the list of species she has seen. If a person, only 2.35 m from the bird, hears the sound with an intensity of 1.9 10-6 W/m2, how far could the bird watcher be from the bird and still hear it? Assume no reflections or absorption of the bird's sound and that the faintest sound that can be heard has an intensity of 10-12 W/m2.

Homework Equations


I2/I1 = (r1/r2)^2
I1 = 1.9e-6 W/m2
I2 = 10e-12 W/m2
r1 = 2.35 m
r2 = ?

The Attempt at a Solution


I rearranged the equation to solve for r2
I got r2 = √(I1 * r1^2/I2)
I plugged in the numbers and got 1024.34 meters
but the problem is saying that I did it wrong.
Is there another formula or did I just mess up somewhere in solving this?
Would appreciate help before Monday.
Thanks
 
Physics news on Phys.org
  • #2
Hey,

See Intensity is inversely proportional to square of distance which is exactly what you used.

So your equations are correct.

Plug in the values again :-)
 
Last edited:
  • #3
emailanmol said:
Hey,

See Intensity is inversely proportional to square of distance which is exactly what you used.

So your equations are correct.

Plug in the values again :-)

Thanks for the reassurance. However, I found out that my value for the Intensity of the threshold of hearing was wrong by a power. Thanks though
 
  • #4
Oh.Lol.!

Yeah using 10^(-11) W/m^2 yields exactly the answer in your Post 1.
 
Last edited:
  • #5


I would approach this problem by first considering the concept of sound intensity and how it relates to distance. Sound intensity is a measure of the amount of sound energy passing through a given area in a certain amount of time. It follows the inverse square law, meaning that as distance from the source increases, the sound intensity decreases proportionally. This means that the further away the bird watcher is from the bird, the lower the sound intensity will be.

Next, I would use the given information to calculate the sound intensity at the bird watcher's distance. Using the equation I = P/A, where I is sound intensity, P is sound power, and A is the area through which the sound is passing, we can solve for P. In this case, P is the sound power of the bird's song, which we do not know. However, we can use the given information about the faintest sound that can be heard (10-12 W/m2) to approximate the bird's sound power. This leads to the equation P = I * A.

We know the sound intensity at the bird watcher's distance (1.9 * 10-6 W/m2) and the area through which the sound is passing (4πr2, where r is the distance from the bird). Plugging in these values, we get P = (1.9 * 10-6 W/m2) * (4πr2). Solving for r, we get r = √(P/(1.9 * 10-6 W/m2 * 4π)).

We can now use the given information about the faintest sound that can be heard to solve for the distance at which the bird watcher can still hear the bird's song. Plugging in the sound power we approximated earlier (10-12 W/m2), we get r = √((10-12 W/m2)/(1.9 * 10-6 W/m2 * 4π)) = 1.15 meters.

This means that the bird watcher could be up to 1.15 meters away from the bird and still hear its song. It is important to note that this is a rough approximation and there may be other factors at play that could affect the sound intensity and the distance at which the bird can be heard. However, based on the given information, this is a reasonable estimate.
 

FAQ: Sound Intensity and Bird Watching

What is sound intensity and how does it relate to bird watching?

Sound intensity is a measure of the strength or power of a sound wave. It is typically measured in decibels (dB). In bird watching, sound intensity is important because it can help identify and locate bird species based on their unique vocalizations. Higher sound intensity can also indicate a bird's proximity, making it easier to spot.

What factors affect sound intensity in bird habitats?

There are several factors that can affect sound intensity in bird habitats. These include the number and type of birds present, the surrounding environment (e.g. open fields vs. dense forests), and weather conditions (e.g. wind, rain). Additionally, human activities such as construction or traffic can also impact sound intensity in bird habitats.

How can sound intensity be measured in bird watching?

Sound intensity can be measured using a sound level meter or a smartphone app with a decibel meter feature. These tools can provide a numerical value for the sound intensity in a given area. Some bird watchers also use their own ears to estimate sound intensity, but this method is less accurate.

Can sound intensity affect bird behavior?

Yes, sound intensity can affect bird behavior in various ways. Loud noises can startle or scare birds, causing them to fly away or stop vocalizing. On the other hand, birds may also use loud sounds to communicate with each other or to warn of potential danger.

Are there any negative effects of sound intensity on birds?

Excessive sound intensity can have negative effects on birds, especially if they are constantly exposed to loud noises. This can cause stress and disrupt their natural behaviors, such as breeding and foraging. In some cases, it may also lead to hearing loss or damage to their vocal cords.

Similar threads

Replies
5
Views
2K
Replies
2
Views
962
Replies
8
Views
2K
Replies
2
Views
2K
Replies
18
Views
2K
Replies
4
Views
3K
Back
Top