Unit 2: The Earth in Space Mr. Ross Brown

Aim: How is our Earth composed? Do now: Drill a hole down through to the center of the Earth. Write down your ideas about the composition of the Earth and the layers that make it up. Be prepared to discuss with the class.

The Earth in Space Taken December 7, 1972, by the crew of the Apollo 17 spacecraft, at a distance of about 45,000 kilometers (28,000 miles). (source: Wikipedia)

In this unit we will learn: The characteristics of Earth’s 3 major zones How seismic waves provide insight into Earth’s interior What the magnetosphere is How the Earth’s gravitational pull is created

What are Earth’s Interior layers? Can’t see inside Earth, but scientists have “seen” with seismic waves, vibrations – Caused by earthquakes or explosions Earth has layers, or zones – Crust: thin, solid, outermost layer – 1% of earth’s mass Mass: the amount of matter in an object – Oceanic Crust: 5km-10km thick – Continental Crust: 15km-80km thick

What are Earth’s Interior layers? – Mantle: 2/3 of the earth’s mass 2,900km thick Upper mantle is cool and brittle (lithosphere) Due to heat and pressure, next layer of rock flows Asthenosphere exhibits plasticity (solid that can flow) – Core Center of the earth, composed mostly of iron Outer core is dense liquid layer Inner core is very dense and solid

What are Earth’s Interior layers? Do now: Compare the thickness of the crust to the thickness of the mantle.

Earth’s Interior layers

Inferred Properties of Earth’s Interior

Seismic Wave Studies Two types of seismic waves – P waves (primary) travel through liquids, solids, and gases. Faster than S waves. – S waves (secondary) travel only through solids. – Core blocks seismic waves in shadow zones

Homework, 13 October 2015 Compare the behavior of P waves and S waves.

What protects the Earth from solar radiation? Do now: What causes the Aurora Borealis?

What is the Magnetosphere? NO!

What is the Magnetosphere? The region in space around our Earth where charged particles are controlled by the planet’s magnetic field Protects us from solar radiation

How does Gravity affect objects on the Earth? Gravity: the force of attraction that exists between all matter in the universe

Newton’s Law of Gravitation The force of attraction between any two objects depends on their masses and the distance between them. Mass is the amount of matter in an object. Weight is an object’s mass and distance from center of the earth.

Newton’s Universal Law of Gravitation states that any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

How does the earth move in space? Do now: Describe the way the earth moves through space over the course of a day and over a year.

How does the earth move in space? Rotation: spinning on an axis. Each rotation is about 24 hours (one day) Revolution: each revolution takes about 365 days (one year)

How does the earth move in space? Earth’s revolution around the sun is slightly elliptical, not quite a circle. Closest to the sun at perihelion, farthest from the sun at aphelion.

How does the earth move in space? Earth’s orbit lies in a plane but earth’s axis is 23.5° from perpendicular to the plane. As earth revolves around the sun, this tilt produces our seasons.

How does the earth move in space?

Thought Question What causes our winter in the Northern Hemisphere?

How does the earth move in space? Do now: Why do we have a Daylight Saving Time?

How do we keep track of time on our earth? The earth is (roughly) a sphere Circumference=360° Every 15° is an hour, 24 hours in a day International Date Line is where the next day begins

World Time Zones

How does the US account for regional time differences? Daylight Saving Time – Goal is more sunlight hours for more work in the summer

Aim: How do we keep track of activity across the earth? Do now: What are some ways we can watch activities/ weather patterns/ disasters all across the earth?

How can we observe our earth? Satellites: Any objects in orbit around other body with a larger mass. Uses: meteorology, communications, navigation, science, military, government Orbits: geosynchronous, polar

Satellite Images