What are the differences between P-waves and S-waves?
P-waves are longitudinal while S-waves are tranvers. This means S-waves can not travel through liquids while P-waves can travel through liquids and solids.
How can P-waves be used to find out about the structure of the Earth?
since S-waves can not travel through liquids there must be something blocking them when an earthquake occurs
Where does refraction occur?
between the boundary between 2 optically dense mediums