use this to do this worksheet:
Test on this


For more on intensity, threshold of hearing, Decibels, etc go to this site:
Now to take care of the (r1/r2)2 you double 10
so = 20 log (r1/r2)

sound2.pngThis this a site that explains the Doppler effect very extensively

When you have sound traveling in air at a different temperature than 0 oC, you have to use the square root of the ratio of the new temperature (in Kelvin) to Standard Temperature (in Kelvin) times the velocity given to calculate the new velocity.



Lab 1

Lab 2

Lab 3

Lab 4


re: 13 Sound
RachelET Jan 21, 2010 7:14 am
I thought that this rotation was very hard. The formulas for the problems can be found in chapter 13 and also chapter 12. Also when a pipe that is open at both ends is submerged in water the ends are closed and a different formula is needed. I thought that it was really interesting but make sure to ask Duncan questions any time you are confused because most of the time the problem is in your math and not the equation or formula. Also the upside down squiggly Y stands for wavelength.
good luck,

CSpears Jan 21, 2010 8:04 am
This chapter is very interesting. It has a lot of interesting facts that are very exciting to learn about. The online packet is not as hard as it may seem. Do NOT over think the problems.
For the online packet:
- do the car and ambulance with the measure of the siren last.
- set the velocity of each moving object
over the other one equal to the given
frequency over the frequency wanted
- p 487 intensity equation
- to do the mosquito question calculate and compare the intensity of each given
- the change in dB is 10 which means its intensity doubles from the other sound.
- the dolphin problem has given information that is not needed. as in the degrees C. when sound travels, it echoes to come back from where it originally came from.
- compare the inverse relationship of the intensity to the radius squared in the rock group problem. (inverse relationship = i1/it=rtsquared/r1squared)
- p 494 fundamental frequency equation
- p 468 wave speed = frequency times wavelength
  • May need to refer to chapter 12 (chapter 12 summary will help. p468)
  • Look at all given charts and equations (p487, 490, 494-497; also ch13 summary p506)
  • watch your problems to which you are working with open-end pipe, closed pipe, string for you equations
  • make sure you understand that wave speed is NOT d/t its FY(upside down Y)
  • book work is easy. all information needed is in the sections.
  • labs are fairly easy also. do NOT over think them.
Good Luck,

tinkzh920 Feb 5, 2010 9:36 am
  • Chp. 13 Sound is not is not a very difficult packet.
  • The formulas needed to work these problems are found on pgs: 487 (intensity equation), 495 (harmonics on a string), 496 (harmonics for open pipes), 497 (harmonics for closed pipes).
  • On some questions frequency is needed for the second or third set of harmonics... because the second set of harmonics is used it does Not mean that the #2 will be used for the harmonic number in the formula...
-ex. for a pipe closed at one end the #3 is used to find the Hz of the 2nd set of harmonics...
REMEMBER: You need to read the question carefully and pay attention to what is being asked. & DON’T BE AFRAID TO ASK MRS.DUNCAN!!!

nchsfelderr Feb 8, 2010 7:17 am
Chapter 13A, like Chapter 12B, is extremely easy if you allow yourself ample time and read Chapter 13. For the online assignment, every formula you need is located between pages 479 and 511. Number 5(the ambulance problem) is very straight forward if you have the correct formulas and I assure you it is in the book. Labs are also straight forward, but do not be like me and put them off to the last few days. Some questions in the labs left me clueless and I didn't have Mrs. Duncan to ask for guidance. Like always, remember to convert units when needed and to be meticulous in your calculations. Good luck!