# Speed of waves in liquids

#### Jacob Aron

For my A level coursework I have to come up with and carry out an experiment. I have chosen to investigate the speed of waves in liquids. I plan to use a ripple tank, set to create waves of a certain frequency, which I will vary. I will measure the wavelength and use the equation v = f&lambda; to find the speed.

I found an equation on http://electron4.phys.utk.edu/141/dec8/December%208.htm [Broken] , which looked to be of use: v = &radic;(gd) where g is acceleration due to gravity and d is the depth of the liquid. I will use this equation to verify the speed.

In the next stage of my investigation, I planned to relate the speed of the waves to the viscosity of the liquid they are in. Intuitivly, I feel there should be a relationship between the two, however, I have not been able to find one online or in textbooks. Also, the fact that v = &radic;(gd) suggests that it doesn't matter what the liquid is, the speed will always be the same for any liquid of the same depth.

Could someone please advise if there is a relationship, or if wave speed is independant of the liquid. Thanks in advance.

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#### gnome

...the fact that v = √(gd) suggests that it doesn't matter what the liquid is, the speed will always be the same for any liquid of the same depth.
I don't know, but I doubt it. You should consider the possibility that v = √(gd) is just a model that someone found to give a reasonably accurate description of some waves in some circumstances, rather than a law of the universe.

You should do your experiment, see what you come up with, and let v = √(gd) be one possible relationship which your results may confirm or contradict.

Keep an open mind.

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