# Speed of Sound greater in denser Materials linked to restoring force

I recently read a book that explained why the speed of sound is faster through a medium with a higher density.

It said -

In a denser medium, the particles are closer together. This means that there is a stronger restoring force so the vibrations are passed more rapidly from one particle to another

I am confused by the statement There is a stronger restoring force which results in the vibrations being passed more strongly.

How does a stronger restoring force cause this? I know that in a denser medium, there are more particles, hence the vibrations can be passed faster from one end to another, but I don't understand how the restoring force is involved.

Thanks.

• look into the derivation of speed of logitudnal wave and note the role of bulk modulus in defining the final formula
– oops
Commented Apr 1, 2017 at 8:29

The speed of sound in lead (density $11.3 \,\rm g\,m^{-3}$) is $1210\,\rm m\,s^{-1}$and in aluminium (density $2.7 \,\rm g\,m^{-3}$) is $6320\,\rm m\,s^{-1}$.