Question

How are scientists able to determine which layers of the earth are solid and which layers are liquid?

Direct Evidence:





Indirect Evidence:

Answer 1

Direct Evidence:By tracking seismic waves, scientists have learned what makes up the planet's interior (figure 2). P-waves slow down at the mantle core boundary, so we know the outer core is less rigid than the mantle. S-waves disappear at the mantle core boundary, so the outer core is liquid.

in direct:Scientists can tell by observing the seismic waves that are recorded all over the surface of the earth from distant earthquakes. The seismic waves are reflected (bounced off) layers of different density, and they are refracted (bent) when they enter layers of different density