Question

in which layer of the earth would you expect to find the least dense materials?
inner core
outer core
mantle
crust

5 multiple choice 1 point
how do temperature and pressure change as the depth of the layers of the earth increases?
temperature and pressure decrease
temperature and pressure increase
temperature increases, pressure descreases
temperature decreases, pressure increases

6 multiple choice 1 point
how do geologists learn about earth’s core?
earthquake waves
mines
temperature measurements
wells

Explanation:

Question 1 (Layer with least dense materials)

The Earth's layers have different densities. The crust is the outermost layer, composed of lighter (less dense) rocks like granite and basalt compared to the mantle, outer core, and inner core which have denser materials (like metals in the core and dense silicate rocks in the mantle).

As depth into the Earth increases, the weight of overlying material increases, so pressure rises. Also, the Earth's internal heat (from radioactive decay and residual heat from formation) means temperature increases with depth.

Earthquake waves (seismic waves) travel through the Earth's layers and change speed/behavior based on the material's properties (density, state). Geologists analyze these waves (like P - waves and S - waves) to infer the composition and state of the core. Mines, temperature measurements, and wells can't reach the core, so they aren't used to study it.

Answer:

D. crust

Question 5 (Temperature and pressure with depth)