1. SPHERES OF THE EARTH

2. What Do We Already Know?
Imagine that you are drilling a hole to the center of the earth. What do you think you would see on this journey?
The Core/Journey to the Center of the Earth

3. Earth’s Layers Earth has four layers:
Crust – the thin crust is the surface layer of the Earth and made of rock.
Mantle – the wide layer beneath the crust that is made mostly of solid rock or some soft rock. (Upper and lower mantle)
Outer Core – made of liquid iron
Inner Core – made of iron and nickel, but it remains solid because of intense pressure.

4. Layers of the Earth

5. Plates
Earth’s crust and upper mantle are divided into sections called plates. Plates are blocks of crust and upper mantle rock that fit together like puzzle pieces.
Plates “float” on the soft rock of the mantle. As this rock flows, it causes the plates to move.

6. Model of Plate Movement
Plates can move in three ways:
Push together
Pull apart
Slide past
Place two textbooks next to each other on your table and model the three different ways that plates can move.

7. Earthquakes
An earthquake is movement of the ground caused by a sudden release of energy in Earth’s crust.
Sandpaper Insta-Lab

8. More Earthquake Terminology
The focus is the place within the crust where energy is released during an earthquake. The epicenter is the point on the surface of the Earth directly above the focus and is where the most damage is likely to occur.
Most earthquakes occur along a fault, or a break in Earth’s crust.

9. The San Andreas Fault

10. How Do Scientist Measure Earthquakes?
Scientists use seismographs to measure the magnitude of earthquakes.
Magnitude, or the amount of energy released, is reported using the Richter Scale.
Seismograph Model

11. Volcanoes
A volcano is a mountain made of lava, ash, or other materials from eruptions.
Magma is melted or molten rock found beneath the surface of the Earth.
Lava is magma that reaches the Earth’s surface.

12. How Do Mountains Form? Mountains are the tallest landforms on Earth .
They form when :
plates come together and part of the crust is forced up.
Pressure is applied to the edges of a plate and rock in the middle is forced upward.
When plates pull apart and magma fills in the gap forming volcanoes.

13. Reading Review What causes Earth’s plates to move?
What causes an earthquake?
How do mountains form?
Which layer of the Earth are we standing on?