8-6 Heat Flow Inside Earth

Essential Question:

How Do People use Earth’s Resource?

How Do Mantle Convection Currents Affect Earth?

Pgs. 296-299

Land, Air, and Water ResourcesMs. De Los Rios

7th Grade

Vocabulary

Convection- The transfer of thermal energy by the movement of a fluid.

Convection Current- The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another.

My Planet Diary pg. 196Dr. Diana RomanHow can you tell when a volcano will erupt? Dr. Diana Roman is trying to find out. She is a volcanologist, a scientist who studies volcanoes. A professor of geology at the University of South Florida, she analyzes data about ground movements to study the motions of magma. Her goal is to find better ways to measure how magma moves so scientists can make better predictions about how and when volcanoes will erupt.

Why does Dr. Roman study the motions of magma below Earth’s surface?

How Do Mantle Convection Currents Affect Earth?

The Earth’s crust is made of minerals, soil, and other important resources which form from hot, molten material deep beneath the

Earth’s surface.

The Earth is made of 3 main layers:

The crust, mantle, and core (inner and outer).

The temperature inside Earth’s

Layers varies from cool to

Extremely hot.

Earth’s Temperature pg. 297

The top of Earth’s Crust is cool but as you go deeper inside the Earth the

temperatures increase as depth increases. Earth’s mantle is hot enough that hard, solid rock can flow. Earth’s core is even hotter.

Where does the heat come from?-Some heat is due to the pressure causedby Earth’s mass pressing down on all sides.-Other heat is due to radioactive substances that release energy.-Finally some is left over from Earth’s formation.

Convection in the Mantle pg. 297The mantle is hot enough that solid rock can flow.

Even though solid- the rock acts like a fluid.

As the rock gets hotter, its density decreases and it rises.

As the rock rises, it gets cooler and its density increases and it sinks.

This process of heat transfer is called convection and is the force behind the convections currents in the mantle.

Convection currents in the mantle transfer heat toward the surface. This causes material to rise toward the surface then sink back into the mantle.

Heat Flow Inside Earth/ Plate Boundaries pg. 298

Mantle Convection Currents cause earthquakes and volcanic eruptions and help to produce mountains and ocean

basins.

Convergent boundaries are plates moving towards each other. When two plates collide, they form mountains. Sometimes, one plate is submerged under the other one, causing part of the plate to melt into magma. When the magma later rises, volcanic mountains form.

Divergent Boundaries pg. 298

Divergent boundaries are plates moving away from each other. As plates move away, rift valleys occur. Molten material rises between the

plates, forming ridges. Over time, ocean basins can form between divergent plates.

Transform Boundaries pg. 298

Transform boundaries are plates moving past each other in opposite directions.

The jagged edges of these plates can lock them into place. However, stress can build up until the plates unlock, causing an earthquake.

Heat Flow Inside Earth pg. 298

Plate MovementConvection currents in Earth’s mantle move the plates. This changes Earth’s surface.

-On the map, where you would expect to find volcanoes forming?

Put a V in the circles.Where would you not expect to find volcanoes?Put an x in the circles.

Reshaping the Surface pg. 299When the plates move at convergent, divergent, or transform

boundaries, they reshape the Earth’s surface. Mountains and volcanoes can form at convergent boundaries.

Rift Valleys and ocean basins can form at divergent boundaries.Earthquakes can form at transform boundaries.

Most changes caused by heat flow are slow, but earthquakes and volcanoes can change the surface very quickly.

Assess Your Understanding pg. 299

1a. List – Heat flow and movement of material inside Earth results in what landforms and events?

b. Explain- How does heat flow inside Earth lead to changes on Earth’s surface?

I get it! Now I know that heat is transferred in Earth’s mantle by ______________________________________________________________________________________________________.