Because the what stops one type of seismic wave slows another scientists believe it is a liquid.?

Scientists believe that the outer core of the Earth is liquid because seismic waves behave differently as they pass through it. Primary (P) waves, which are compressional waves, can travel through both solids and liquids, while secondary (S) waves, which are shear waves, cannot travel through liquids at all. The fact that S waves do not reach the other side of the Earth indicates that the outer core is not solid, supporting the conclusion that it is indeed liquid. This distinction helps geologists understand the Earth's internal structure.