Changes Within Changes Within the Earththe Earth

Coach ParrishCoach Parrish

77thth Grade History Grade History

Oxford Middle SchoolOxford Middle School

Physical CharacteristicsPhysical Characteristics GeologyGeology – the study of the earth’s physical – the study of the earth’s physical

structure and history.structure and history.

The Earth’s LayersThe Earth’s Layers1.1. CoreCore – center of the earth that consists of – center of the earth that consists of

very hot metal, mainly molten lava.very hot metal, mainly molten lava.2.2. MantleMantle – a thick layer of rock that surrounds – a thick layer of rock that surrounds

the core. Scientists measure the mantle at the core. Scientists measure the mantle at 1800 miles thick.1800 miles thick.

3.3. CrustCrust – the outer layer of the earth. – the outer layer of the earth. Scientists measure the crust to be about 5 Scientists measure the crust to be about 5 miles thick.miles thick.

The Earth’s LayersThe Earth’s Layers

Land, Air, and WaterLand, Air, and Water

The area on and around the earth is The area on and around the earth is made up of “spheres.”made up of “spheres.”

1.1. LithosphereLithosphere – Soil, rocks, landforms and – Soil, rocks, landforms and other surface features.other surface features.

2.2. AtmosphereAtmosphere – the layer of air and water – the layer of air and water about the earth.about the earth.

3.3. HydrosphereHydrosphere – consists of water in – consists of water in oceans, lakes, and rivers on the earth.oceans, lakes, and rivers on the earth.

4.4. BiosphereBiosphere – world of plants and animals – world of plants and animals on the earth.on the earth.

Physical ProcessesPhysical Processes

Physical processes help to shape the Physical processes help to shape the landforms on earth in the form of landforms on earth in the form of volcanoes and earthquakes.volcanoes and earthquakes.

VolcanoesVolcanoes – form when magma from – form when magma from the earth’s core break through the the earth’s core break through the earth’s crust.earth’s crust.

Explaining Volcanoes and Explaining Volcanoes and EarthquakesEarthquakes

Most scientists agree that Volcanoes Most scientists agree that Volcanoes occur because of plate tectonics.occur because of plate tectonics.

Plate tectonicsPlate tectonics – theory that the – theory that the earth’s crust is made up of many earth’s crust is made up of many movable plates that cause volcanoes movable plates that cause volcanoes and earthquakes.and earthquakes.

VolcanoesVolcanoes Over time, as volcanoes continually erupt, Over time, as volcanoes continually erupt,

the lava cools and hardens adding layers the lava cools and hardens adding layers to the Earth. These examples are from to the Earth. These examples are from Mt. Fuji – Japan.Mt. Fuji – Japan.

Ring of FireRing of Fire

Ring of FireRing of Fire – series of mountains created – series of mountains created by volcanoes surrounding the Pacific Ocean.by volcanoes surrounding the Pacific Ocean.

EarthquakesEarthquakes

The movements of earth’s crust can The movements of earth’s crust can sometimes cause earthquakes. When sometimes cause earthquakes. When rocks on either side of a fault move rocks on either side of a fault move suddenly, an earthquake occurs. suddenly, an earthquake occurs.

The next slide shows where the fault The next slide shows where the fault lines are located on the earth and lines are located on the earth and what they look like!what they look like!

Fault Line PictureFault Line Picture

Continental Drift TheoryContinental Drift Theory

During the 1600s, people started noticing During the 1600s, people started noticing that the continents could have fit together that the continents could have fit together at one time.at one time.

In the early 1900s, a German explorer and In the early 1900s, a German explorer and scientist named Alfred Wegener scientist named Alfred Wegener suggested the continental drift theory.suggested the continental drift theory.

Continental Drift TheoryContinental Drift Theory – idea that at one – idea that at one time, earth only had one continent called time, earth only had one continent called Pangaea. Over time, the continents Pangaea. Over time, the continents separated into what we know today.separated into what we know today.

Continental Drift TheoryContinental Drift Theory Here is a picture of the continental drift theory.Here is a picture of the continental drift theory.