Sound is a mechanical wave created by vibrating objects, measured in decibels (dB) with a reference intensity level of 0 dB at 10^-12 w/m2. The document explains how to calculate sound intensity levels and intensities using specific equations and examples from soccer and basketball games. It demonstrates the process of finding sound intensity levels and intensities through calculations based on known values.

2.  Everyone is familiar with sound, we have ears
to detect it after all!
 But what is sound?
 Sound is a mechanical wave which is created by a
vibrating object.
 But how do we measure it?

3.  Sound Level Meter

4. http://windchimes.co.za/photos/sound_intensi
ty_levels.gif

5.  Unit: Decibel (dB)
 Reference sound intensity level of 0 dB is an
intensity of: I0=10-12 W/m2 (the quietest sound
a human ear can detect)
 All other sound intensities are measured in
reference to this threshold hearing intensity.

6.  When comparing a specific sound intensity to
the reference intensity (Io), it’s known as
sound intensity level.
 Equation:
 Where B= “bel”
 I= specific sound intensity
 I0 reference intensity (I0=10-12 W/m2 )

7.  You are at the Mariners soccer game where
you are told the sound intensity is 10^-20
W/m2.What is the sound intensity level?
*Hint*:What are you trying to find?*

8.  Since you know sound intensity level corresponds to “B”,
you would use the equation below and simply plug in the
values you know.
 I= reference intensity= 10^-12 W/m2
 I0= 10^-20 W/m2
 B= what you are trying to find.
 Calculate!
 Answer: 80 dB

9.  You are at theThunderbird Stadium watching
a basketball game, where you find out the
sound intensity level is 100 dB.What is the
sound intensity inW/m2?

10.  You will need to rearrange the sound
intensity level equation, to find sound
intensity (I) inside theThunderbird stadium.

11.  Plug in known values:
 Divide by 10:

12.  Since it’s log base 10, everything can be written in base 10:
 Isolate for I0=
 FinalAnswer: 10-22W/m2
*To check*: Just plug back into original equation

13. 