Question

quiz: convection and the mantle
use the diagram and your knowledge of convection currents to help you answer the following questions.

1. where are convection currents found?

1. convection currents are caused by

differences in what two things?

1. explain what is happening at each point on the diagram.

a.

b.

c.

d.

Explanation:

1. Convection currents in Earth's structure form in the semi-fluid mantle, driven by heat from the core.
2. Convection relies on differences that change material density: temperature (which affects particle motion) and density itself, as warmer, less dense material rises and cooler, denser material sinks.

3.

• Point A: Near the hot outer core, mantle material is heated, becomes less dense, and begins to rise.
• Point B: The rising material reaches the cooler lithosphere (top of the mantle), loses heat, becomes denser, and starts to sink.
• Point C: The cooler, denser mantle material moves horizontally along the base of the lithosphere, transferring heat outward.
• Point D: The sinking material is pulled back toward the core, where it is reheated to restart the cycle.

Answer:

1. In Earth's mantle (specifically the asthenosphere and lower mantle)
2. Temperature and density

3.
A. Mantle material is heated and rises
B. Mantle material cools and begins to sink
C. Cooled mantle material moves horizontally
D. Sinking material is reheated near the core