PLANET EARTH:WHAT IS IT MADE OF

AND HOW DOES IT CHANGE?

Planet Earth Unit

Topic 1 (Pgs. 352-366)

How were these Alberta landforms created?

What do YOU think is in our planet?

Geologists are scientists that study the Earth

The Layers of Planet Earth

The Layers of Planet Earth

The CrustThe outer layer of

Earth, made up of the features we see (mountains, valleys, hills, plains, etc.)

This layer is bout 10-90 km thick (the thinnest of all the layers)

The MantleThe upper mantle is

solid like the crustThe lower mantle

melted rock that flows slowly (very hot here)

This layer is 2900 km thick and makes up 67% of the Earth’s mass

The crust and the upper mantle (solid layers) form the lithosphere

The Layers of Planet Earth

The Outer CoreThis layer is so hot

that rock is completely liquefied (molten)

This layer is about 2200 km thick

The Inner CoreThis layer is solid

even though it is VERY hot (7000°C)

The massive pressure from the other layers press the inner core into a hard ball of metals

This layer is about 1250 km thick

The Earth changes all the time, sometimes very quickly and sometimes very slowly

Sudden ChangesEarthquakesVolcanoesTsunamisHurricanesTornados

Long-Term ChangesErosion

○ Wind ○ Water○ Ice

Weathering

Earthquakes What is an

earthquake?

How does an earthquake happen?

What are some of the side effects of an earthquake?

How Earthquakes Work The first place where

the rocks below the surface break is called the focus, and occurs along fault lines

The energy released by this sudden break is called spreads as waves called seismic waves

The point on the surface of the Earth directly above the focus is called the epicentre

Geologists use a seismogram to locate the epicentre and provide aid to those injured

The Richter ScaleRichter scale no. No. of

earthquakes per year

Typical effects of this magnitude

< 3.4 800 000 Detected only by seismometers

3.5 - 4.2 30 000 Just about noticeable indoors

4.3 - 4.8 4 800Most people notice them, windows rattle.

4.9 - 5.4 1400Everyone notices them, dishes may break, open doors swing.

5.5 - 6.1 500Slight damage to buildings, plaster cracks, bricks fall.

6.2 6.9 100Much damage to buildings: chimneys fall, houses move on foundations.

7.0 - 7.3 15Serious damage: bridges twist, walls fracture, buildings may collapse.

7.4 - 7.9 4 Great damage, most buildings collapse.

> 8.0One every 5 to 10

yearsTotal damage, surface waves seen, objects thrown in the air.

Volcanoes A volcano is an

opening in the Earth’s crust that allows solid and molten rock to escape

Volcanoes are easier to predict than earthquakes

Magma - molten rock within the Earth

Lava - molten rock that flows out of a volcano

Ash - small, burnt particles from a volcanic eruption

Gradual Changes to the Earth

Weathering The process of

breaking down rocks by water, wind, or ice

Erosionoccurs when the

pieces of rock broken down from weathering move from place to place

3 Types of Weathering

1. Mechanical Rocks are broken apart by forces, like wind

or water

2. Chemical Rocks are broken apart by chemicals, like

acid rain or air pollution

3. Biological Rocks are broken apart by living things, like

tree roots or animal/human use

The Power of Moving Water As rivers flow they carry sand, gravel,

mud these are called sediments As these sediments sit on the bottom of

lakes, rivers, oceans they become hard rocks this is called sedimentation

Fast vs. Slow

Landslide

Glaciers slowly grow and shrink, scraping the Earth’s crust as

they move