What is the effect on amplitude when sound travels from air to water?
Answers
As you might know Sound travels as a longitudinal wave which means it travels using the particles in the medium it is travelling. Sound basically transfers energy from one particle to another causing a transverse wave which transfers sound energy from one place to other.
Now, coming to your question, while passing through air, as the particles are apart from each other thus speed of sound is lesser as there aren't much densely packed particles to carry the wave forward. But, the energy with which the sound is made is constant which causes frequency to be constant just that wavelength is small as speed is less.
Now, in a denser medium such as water, the particles are closer to one another, so the speed is increased but, as the energy with which the sound was made is again the same, the frequency remains constant increasing the wavelength to maintain the speed.
Basically, it is due to conservation of energy principle that as speed of sound increases, it's wavelength is adjusted instead of it's frequency