Science - Ch. 5, Lesson 2: Convection and the Mantle (Questions)

Describe how convection currents form.

A heat source nearby heats the fluid. Molecules move faster and spread apart. The density decreases and fluid rises away from the heat source. The fluid cools and molecules move slower and together. The density increases and fluid sinks back towards the heat source.

How is heat transferred through space?

By electromagnetic (energy) waves during radiation

What causes convection currents in Earth's mantle?

Heat from the core and the mantle (compared to the coolness at the crust) causes convection currents in the mantle

What is a convection current?

Movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another

What will happen to the convection currents in the mantle if Earth's interior eventually cools down? Explain.

The convection currents would stop because the currents would no longer have a heat source for the difference in temperature.

What part of Earth's interior is like the burner on a stove top? Explain.

The core because it is the heat source for the convection currents in the mantle.

What part of Earth's interior is like soup being heated in a pot? Explain.

The mantle because the convection currents are happening in the mantle.

Name two layers of Earth in which convection currents take place.

The outer core and mantle

In general, what happens to the density of a fluid as it becomes hotter? As it becomes cooler? Explain.

When a fluid becomes hotter, the density decreases because the particles move faster and move apart (volume increases). When a fluid becomes cooler, the density increases because the particles move slower and move together (volume decreases).

Name and describe 3 methods of heat transfer.

Convection, conduction, and radiation. Convection is the transfer of thermal energy by the movement of a fluid. Conduction is the direct transfer of thermal energy from one substance to another substance that it is touching. Radiation is the direct transfer of energy through space.