# Early attempts at determining the speed of sound?

1. Jan 28, 2005

### BigRedRod

As the title suggests, I'm curious about the first experiments to find the speed of sound and who developed/performed them. Who was the first to really have a good crack at it? And who came up with the equations to how it varies under differing conditions?

We hear all the time about other attempts at defining physical constants but I have no idea about this one (I'm aware it isn't really a constant, due to variation with air density and temperature, but still, you get my drift I'm sure)

So can anyone shed any light on this subject?

2. Jan 28, 2005

### christinono

I have a vague idea of it. My physics teacher last year told us a bit about it... shows how much I really paid attention... He said someting about a large field with 1 guy at each end. One of them had a bell, or some other device that made a large sound. They measured the time for the sound to travel the distance of the field. I don't remember what their names were. Sorry I can't be of more help...

3. Jan 28, 2005

### kirovman

I am not exactly sure, but I know something about early attempts to measure light speed. They deduced that the speed of light was at least 8 times the speed of sound I think, but the experiment inherantly inaccurate as it realied on human reaction times.

I imagine early speed of sound experiments were similar...make a noise at the same time as make an optical signal. The speed of sound could easily be obtained.

As for equations under different conditions, I'm not sure on that one.

4. Jan 28, 2005

### The Bob

i believe the earliest test was done in about 1870 after an idea by Galileo. (All of that might be wrong but the next bit is true).

Two people were to have lanterns and they would get used to turning them on simulatious. They were then seperated by about 3 miles, told to turn the lights on at almost the same time and then the time it took to get from on lantern to the other was measured by the time it took for the other person's lantern to be seen. The distance was too close and the human error was too great for it to be accurate.

Then there was another person that noticed the positions on Jupiter's Moons in relation to the Earth and noticed that they were behind schedule on month and ahead of it another. He predicted the speed of light to be $$2.98$$ $$\times$$ $$10^8 ms^{-1}$$. The person that did this even told scientists that an eclipse of one of Jupiter's Moons would be 10 minutes late to what people thought and he was right.

P.S. If you really want more details I will have to get out of my chair and go and get my sheet from my physics class.

5. Jan 28, 2005

### vincentchan

BoB:
are we talking about sound or light??

the first experiment finding speed of sound....Hm..... I think it was done a couple thousands years ago..... when our ancestor observse the sound of the lightening always come after the light.... By dividing the distance where the lightening strike and the time lags between the light and sound, you will approximately calculate the speed of sound... with a very good accuracy

6. Jan 28, 2005

### The Bob

We are all allowed an off day. I am talking about light but he rest of you are not so I feel a little bit stupid

OH WELL