Unit 7: Convection Current in Earth

Convection Currents and the Mantle

3 Types of Heat transfer

• Radiation- transfer of heat through empty space

• Conduction- transfer of heat by direct contact

• Convection- transfer of heat involving the movement of fluids-liquids and gases

Multiple Choice

The transfer of heat by direct contact is ...

• radiation

• conduction

• convection

Multiple Choice

The transfer of heat through empty space is ...

• radiation

• conduction

• convection

Multiple Choice

The transfer of heat involving the movement of fluids-liquids and gases is ...

• radiation

• conduction

• convection

Density

The relationship between the amount of matter (mass) in a set space (volume).

Multiple Choice

What is density???

• the amount of mass in an object

• the amount of volume it takes up

• the amount of mass in a given volume

Models of Earth

Understanding the upper mantle: Asthenosphere

• Heat from Earth’s core and mantle causes the temperature of rocks to change.

• This changes the density of the rock.

• Hot columns of mantle (rock) material rise toward the surface.

• Hot material reaches the surface and begins to cool. As it cools, it increases in density and begins to sink.

Convection Currents

• Density - a measure of how much mass there is in a given volume

• Convection Current - the flow that transfers heat within a fluid

• Convection currents work by warmer, less dense, fluid rising and colder, more dense, fluid sinking

Convection Currents

• ***These 3 things set convection currents in motion***

• Heating and cooling of a fluid

• Changes in the fluid's density

• The force of gravity

​Lesson 5.1: Convection and the Mantle

Solids are capable of flowing just like liquids in certain conditions. In this Lava Lamp, a light bulb generates heat that causes globs of wax to expand and become less dense. As their density decreases, they float upwards away from the light where they cool back down and start to sink to the bottom

​How does Convection Occur in Earth's Mantle

• The mantle and core of the Earth are extremely hot

  • Heat inside the Earth originated​ from gravitational energy and decay of radioactive elements

• Heat transfers from the mantle and core in different ways

Grade 8 Science Ohio | Lesson 5.1

​Convection Currents

Grade 8 Science Ohio | Lesson 5.1

Multiple Choice

What does a convection current transfer within a fluid?

• heat

• air

• water

• smoke

Multiple Select

Which Layers of the Earth experience Convection Currents? (Mark all correct answers)

• Crust

• Mantle

• Asthenosphere

• Inner Core

Multiple Choice

Not all planets in our solar system have tectonic plate motion.

What would happen to convection currents if the inner Earth Cooled down?

• The convection currents would continue at the same speed

• The convection currents would move faster.

• The convection currents would move slower.

• The convection currents would stop.