# Bulk modulus of Liquid helium and first sound

Does anyone know where to find the bulk modulus of liquid helium ?

I've been looking all over the internet but everywhere I get N/A. Any tips ?

I'd need it to estimate the speed of first sound in liquid helium which is given by:

$c_1=\sqrt{\left.\frac{\partial p}{\partial\rho}\right|_\sigma}$

## 2 Answers

A Google books search for "bulk modulus of liquid helium" turned up this result: Helium, edited by Paul Muljadi. On page 7, you will find the value of the bulk modulus as on the order 50 MPa. There is a reference linked to this value, but it is not part of the free preview, so I cannot tell you what it is.

• Alrighty! Thanks a lot already ! I'll look into it, seems to give the correct value for the speed of first sound (more or less). – Nick Dec 3 '13 at 19:10
• Seems also that this 50MPa is for solid Helium and not liquid helium (that should be somewhere around a factor 1000 lessà – Nick Dec 3 '13 at 19:22
• Ah, well I tried. I bet searching through the other books in the Google-book search might pop up something more accurate. – Kyle Kanos Dec 3 '13 at 19:34
• Yeah, at least thanks for trying! I've been looking on physical review letters etc. Not even [WolframAlpha][1] was able to find it. Currently I'm looking in google-books, great tip :). [1]:wolframalpha.com – Nick Dec 3 '13 at 19:36

The best way is to use the inverse value, the compressibility, this one is more easilly found.