what have scientist learned about p waves and s waves in the inner core?

Answer 1

S waves don't make it to the inner core. They cannot go through liquid so they are stopped at the outer core. That's how Sir Harold Jeffreys discovered that the outer core was liquid. Inge Lehmann discovered that the inner core was solid because if the change in velocity that the P waves made at a certain point. This was due to a density change going from molten iron-nickel to solid iron-nickel. She notice the reverse change when the P wave came back out the other side.