Seismic refraction is the bending of the seismic waves as they pass geological layers of the earth due to different densities. This is especially true for Primary waves because they can pass through all the layers of the earth both liquid and solid.
Seismic reflectivity is the bouncing back of seismic waves at a boundary of geological layers due to different densities or subsurface formation. This is especially true for secondary waves that are unable to pass through liquid layers of the earth like the outer core and mantle. When they reach the boundary of these layers they bounce back towards the earth's surface.
These properties of P and S waves are used to ‘auscultate’ the epicenter of an earthquake by triangulation.
Learn More:
For more on Seismic Reflection and Seismic Refraction check out;
The term you need to know is equilibrium. Technically it means that heat gained = heat lost. Normally in beginning chemistry classes the evidence for this condition is a stable temperature.
