Question

mid - term study guide

1. label the layers of the earth
2. what heats the center of the earth?
3. what moves the tectonic plates?
4. when two plates collide, what boundary is it?
5. when two plates drift away from each other, what boundary is it?
6. when two plates slide past each other, what boundary is it?
7. when one plate goes under another, what is it called?
8. describe the convection currents that occur in the mantle.
9. what are seismic waves?
10. compare and contrast the two types of seismic waves.

Explanation:

1. The Earth's layers are the crust, mantle, outer - core, and inner - core. The crust is the outermost layer, the mantle is below the crust, the outer - core is liquid and the inner - core is solid.
2. The center of the Earth is heated by radioactive decay of elements such as uranium, thorium, and potassium, and residual heat from the Earth's formation.
3. Tectonic plates are moved by convection currents in the mantle. Hot, less - dense material rises, cools, and then sinks, creating a circular motion that drives the plates.
4. When two plates collide, it is a convergent boundary.
5. When two plates drift away from each other, it is a divergent boundary.
6. When two plates slide past each other, it is a transform boundary.
7. When one plate goes under another, it is called subduction.
8. Convection currents in the mantle occur due to the heat from the Earth's core. Hot material rises, cools as it moves towards the surface, then sinks back down as it becomes denser.
9. Seismic waves are waves of energy that travel through the Earth's layers, generated by events like earthquakes, volcanic eruptions, and explosions.
10. There are two main types of seismic waves: P - waves (primary waves) and S - waves (secondary waves). P - waves are compressional waves that can travel through solids, liquids, and gases, and are faster. S - waves are shear waves that can only travel through solids and are slower.

Answer:

1. Crust, Mantle, Outer - Core, Inner - Core
2. Radioactive decay and residual heat from formation
3. Convection currents in the mantle
4. Convergent boundary
5. Divergent boundary
6. Transform boundary
7. Subduction
8. Hot material rises, cools, and sinks in the mantle due to heat from the core
9. Waves of energy traveling through Earth's layers
10. P - waves: Compressional, can travel through solids, liquids, and gases, faster; S - waves: Shear, can only travel through solids, slower