Transcript Changes within the Earth

Changes Within the
Earth
Coach Parrish
7th Grade History
Oxford Middle School
Physical Characteristics

Geology – the study of the earth’s physical structure
and history.
The Earth’s Layers
1.
Core – center of the earth that consists of very hot
metal, mainly molten lava.
2.
Mantle – a thick layer of rock that surrounds the core.
Scientists measure the mantle at 1800 miles thick.
3.
Crust – the outer layer of the earth. Scientists
measure the crust to be about 5 miles thick.
The Earth’s Layers
Land, Air, and Water

1.
2.
3.
4.
The area on and around the earth is made up of
“spheres.”
Lithosphere – Soil, rocks, landforms and other
surface features.
Atmosphere – the layer of air and water about the
earth.
Hydrosphere – consists of water in oceans, lakes, and
rivers on the earth.
Biosphere – world of plants and animals on the earth.
Physical Processes

Physical processes help to shape the landforms
on earth in the form of volcanoes and
earthquakes.

Volcanoes – form when magma from the earth’s
core break through the earth’s crust.
Explaining Volcanoes and
Earthquakes

Most scientists agree that Volcanoes occur
because of plate tectonics.

Plate tectonics – theory that the earth’s crust is
made up of many movable plates that cause
volcanoes and earthquakes.
Volcanoes

Over time, as volcanoes continually erupt, the
lava cools and hardens adding layers to the
Earth. These examples are from Mt. Fuji –
Japan.
Ring of Fire

Ring of Fire – series of mountains created by
volcanoes surrounding the Pacific Ocean.
Earthquakes

The movements of earth’s crust can sometimes
cause earthquakes. When rocks on either side of
a fault move suddenly, an earthquake occurs.
The next slide shows where the fault lines are
located on the earth and what they look like!
Fault Line Picture
Continental Drift Theory

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During the 1600s, people started noticing that the
continents could have fit together at one time.
In the early 1900s, a German explorer and scientist
named Alfred Wegener suggested the continental
drift theory.
Continental Drift Theory – idea that at one time,
earth only had one continent called Pangaea. Over
time, the continents separated into what we know
today.
Continental Drift Theory

Here is a picture of the continental drift theory.