A powerpoint summary about measuring sound, specifically about sound intensity levels and it's unit, equation and manipulating the equation to calculate specific values in two separate questions. (Error was initially made in calculation #1 has been corrected and answered and explained further)

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.  A)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?
b) Is this level lower or higher than the threshold of
human hearing?
*Hint*:What are you trying to find?*

8.  A) Since you know sound intensity level corresponds to “B”, you
would use the equation below and simply plug in the values you
know.
 I= specific sound intensity= 10^-20W/m2
 I0= reference intensity= 10^-12W/m2
 B= what you are trying to find.
 Calculate!
 Answer: -80 dB
b) Since the answer is negative it’s indicating that the sound is below
the threshold level for human hearing (because the threhold for
human hearing is 0 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. 