Speed of sound?

Question

Can anyone think of a simple procedure to calculate the speed of sound that 8th graders could do in class?

WITHOUT SHOUTING!! like with a microphone and stuff?

Answer 1

Yes, you will need a microphone with a long cord and a computer with n-track recording software on it.

Most recording software comes with the ability to generate tones. Have it generate a single square wave (at whatever frequency you want).

Then bring the mic all the way to the other side of the room (or as long as the cord will stretch). Have the computer play the sound you create while recording on a secondary track. Then look at the two tracks (you will have to zoom in on them), you will be able to see a delay between the sound in the first and second tracks. Since you made a square wave, it will be very clear how much delay there was.

Find out how many milliseconds difference there is between the two, and divide the distance from the speakers to the mic by that number, then divide by 1000, and you have your sound in ft/s.

Answer 2

Instead of shouting (which I can imagine would be waaayyy to much fun for 8th graders and you'd have a difficult time getting them to stop :) and also you can't control the length of time they would shout) how about a pair of wooden blocks and clap them together. You'd get a distinct, short, loud sound. Then have the group be away from the wall a good distance and have the person clapping the wooden blocks synchronize their clapping with their hearing the echo. Then, all you have to do is use a stopwatch to measure the time between claps, which will make the measuring easier, since with a little practice the clapping will be fairly regular. You can do it ten or twenty times and then average the measurements. Then, take the times and use the distance from you to the wall (remember the round-trip is twice the distance from you to the wall, so either double the distance or divide your times by 2) to calculate the distance per amount of time.

The farther you can be from the single wall, the better. Since sound is moving at over 1100 feet per second, if you are a couple of football field lengths away from the wall, you can get slightly more than a full second between claps.

You could also use balloons and pop them to make the sound and record the time for the echo to come back to you. This would require that the students blow up a bunch of balloons and that would be a fun activity....

Have fun!

Answer 3

You want a procedure to measure the speed of sound. Here's an easy way:

Go into an open area with a large, flat faced building at one end (perhaps the school sports oval, with a large building at one end). It needs to be a distance of about 100m (100 yards).
What you need is a place where you can make a noise, and hear the echo. You may need to do this at night, when the air is still.

When you find a place that produces a good echo, then perhaps the teacher could borrow a starting pistol or loud cap gun and a stopwatch.

Time the period between the bang and the echo, then measure the distance between you and the building (remember to double the distance to allow for the original noise, and the return of the echo). You have to be quick, because as other answerers have noted, you will have less than a second to measure. (Perhaps take several measurements, and compare. This is also a good experiment to determine experimental error.)

Answer 4

How about this very simple calculation.

Distance = Rate*Time so, Rate = Distance/Time

Rate = 769.5 mph (constant speed of sound)

Here is a word problem.
Wayne is standing 10 miles away from a fireworks display. He has a stop watch that tells him it took 46.8 seconds for the sound to reach him. Calculate the speed of the sound of the fireworks on miles per hour (mph).

The question gives us distance and time but the time needs to be converted to hours before it is put into the question. This part adds a little to the problem but not too much for an eigth grader.

To convert second to hours use the following

46.8s*(1min/60s)*(1hr/60min) or 46.8s/3600 = .013 hr
Plug this into the algebraically manipulated equation R= D/T

10 mi / .013 hr = 769.2 mi/hr or about 769.5 mph

Answer 5

Yes at sea level the speed of sound is about 1000 ft per second . Makes for a simple calculation.

Answer 6

hey there!

here's a sure answer,

speed of sound is 331m/s
as the temperature increases, the speed of sound does too
so if there is a specified temp, here's the equation:

331+.6(temperature)
(just add 331 to the product of the temp & .6)
(.6 is the rate of increase in the speed's sound for every second)
i hope i helped you!

Answer 7

u need a stop watch and an open field of known length.

get them to an open field of known length, ask two students to stand at opposite ends of the field. one of them is to shout,or make some form of noise or sound, and the other is to put their hand up as soon as they hear the sound. u need to start the stop watch as soon as the 1st student makes the sound and stop it as soon as the 2nd student puts his/her hand up. note the time taken.

calculation time:
speed = distance / time, therefore
speed of sound = length of field/ time recorded.

the speed of sound is 343m/s but any answer btw 300m/s and 345m/s is a good approximation.
hope this isn't too complicated and it helps.
good luck!

Answer 8

Well, you just need to remember this. Through air, sound travels at around 343 metres per second. Using that information, you can work out any question.