The Earth’s Layers, Axis, & Plate Tectonics

Milky Way Galaxy

Our Solar System

Earth’s Layers

• The Earth is made of 3 layers- – crust– mantle– core (inner and outer)

• The circumference of the earth at the equator is 24,902 miles

• The circumference of the earth at the poles is a bit shorter - 24,860 miles

• Equatorial bulge caused by Earth’s spin and sun/moon’s gravity

Layers of the Earth

What is the diameter?

• It is the distance from one side to the other.

What is the circumference of the Earth?

• The distance around the Earth.

• Almost 25,000 miles

Size of the Earth

Earth Stats

• 93 million miles from sun

• While we're hurtling through space at nearly 67,000 mph, we're also spinning around in circles at over 1,000 mph!

• The Sun is a fusion nuclear reaction- it powers the whole system.

Sun

• Provides light, heat, and energy.

• Compressed hydrogen and helium gas

• 10,800 degrees F

Earth’s axis

• Earth is divided into hemispheres- – Equator divides N & S– Prime Meridian divides E & W

• Earth’s Axis- inclined (tipped) 23.5° - causes seasons- the uneven distribution of heat causes ocean currents and the weather

Movement of the Earth

• Rotation of the Earth• 23 hours 56 min.• 1 day

http://www.sciencenetlinks.com/interactives/messenger/psc/

PlanetSize.html

Revolution of the Earth

• Revolution– One trip

around the sun.

• 364 ¼ days• 1 year

Tilt & Temperature

Distance from Sun

• Minimum Distance from Sun: (91 million miles or 147 million kilometers)

• Maximum Distance from Sun: (94.5 million miles or 152 million kilometers)

Assignment:Describe the position of the Earth through each season. Change of Seasons and Tilt of Earth

•The season is fall.

•The direct rays of the sun shine at equator.

•Day and night are equal because the Earth is not tilted toward or away from the sun.

Continental Drift

• Earth’s crust is broken up into plates which float around on magma and bump into each other.

• Plates move at a rate of between ½ to 4 inches annually

• “Inside our planet” (4:03)– http://www.bbc.co.uk/science/earth/

surface_and_interior/inside_the_earth#p00gfcjk

Continental Drift• Convergence- when 2 plates come together,

forming mountains• Subduction- when 1plate slides under the

other• Divergence- when magma rises to the

surface, creating new ocean floor- sea floor spreading

• Transform- when 2 plates slide against each other- fault line

• Continental rift- when a continent is pulled apart

Interactive earthquake/tectonic plate link

• “The Earth’s Plates” (4:18)– http://www.bbc.co.uk/science/earth/

surface_and_interior/inside_the_earth#p00fztvj

• Tectonic plates review– http://www.bbc.co.uk/schools/gcsebitesize/

geography/natural_hazards/tectonic_plates_rev1.shtml

– http://news.bbc.co.uk/2/hi/science/nature/7533950.stm

Landforms

• Create a map of your own country. Choose 10 landforms to label on the map. Define them on the back and provide a real world example. Color the map. Good Luck!

• Archipelago, bay, canal, canyon, cape, channel, cliff, continental shelf, continental divide, delta, fork, river source, river mouth, glacier, gulf, harbor, highland, hill, island, isthmus, lake, mountain, ocean, peak, peninsula, plain, plateau, sound, strait, swamp, tributary, valley, volcano, fjord