The Earth and it’s Layers

The Earth’s Structure A. Earth consists of a series of concentric layers or spheres which differ in chemical and physical properties. B. The compositional layers of the Earth are the Crust, the Mantle, and the Core. The Core is subdivided into a molten outer core and solid iron inner core.

The Earth’s Structure C. Physical state is determined by the combined effects of pressure and temperature. 1. Increasing pressure raises the melting point of a material. 2. Increasing temperature provides additional energy to the atoms and molecules of matter allowing them to move farther apart, causing the material to melt.

The Earth’s Structure 3. Both pressure and temperature increase toward the center of the Earth, but at different rates. Density also increases as you reach the center. 4. Divisions of the Earth based upon physical state (mechanical layers) are the Lithosphere, the Asthenosphere, the Mesosphere, the Outer core, and the Inner core.

Isostacy Isostacy refers to the balance of an object when “floating” on a fluid. This is best seen with ice in water, or iceburgs in the ocean.

Isostacy This also happens to rocks in the Earth. BUT ROCKS AREN’T FLUIDS! If you put enough pressure on something, it will gradually act like a fluid. There is A LOT of pressure in the Earth. As you move towards the center of the earth, each layer gets denser than the last.

Earth’s crust is dynamic (moving)

Layers on Earth’s Surface Three fluid (meaning they move) spheres surround the rocky portion of the Earth. 1. Hydrosphere includes all of the "free" water of the Earth contained in the ocean, lakes, rivers, snow, ice, water vapor, and groundwater. 2. Atmosphere is the gaseous envelope that surrounds the Earth and is mainly a mixture of nitrogen and oxygen. 3. Biosphere refers to all living and non-living organic matter. 4. Lithosphere includes all rock and land.

Draw this figure in your notes

Make and label this model:

The Ocean Floor Bathymetry of the Earth Bathymetry- the underwater landscape. Any feature that you see above water you can find under the sea, however some features we find underwater aren’t found on land.

The Ocean Floor

The seafloor is divided up into 3 major provinces Continental Margins Abyssal plains Mid-Ocean Ridges

Continental Margins Continental margins – submerged edges of the continents Made up of deposited material from land erosion is again divided into 3 zones Continental shelf Continental slope Continental rise

The Continental shelf If you have ever waded out into the water at the beach you have stood on the cont. shelf Extends out to an average depth of 130m and terminates at the shelf break Shelf break – where the seafloor begins to get steeper 1-4 degrees

The Continental slope 1-4 degrees downward slope Extends out until water is about 2-3 km deep (kilo- 1000) Parts of this steep slope are cut by deep canyons (submarine canyons)

Continental rise Vast sedimentary plane About 1 degree slope About 4 km deep Joins with the Abyssal plains

Deep Ocean Providence Located between the Continental Margins and the Mid-Ocean Ridges Mostly flat Abyssal plains flat plains to .5 degree slopes 3-5 km deep Some of the flattest places on Earth

Mid-Ocean Ridge Normally found in the middle of the ocean Where sea-floor spreading occurs Has a rift valley (indention on the top of the mountain chain) where volcanic activity occurs Not all oceans have a mid-ocean ridge

Other Features Trench – very deep valley found in some oceans, where seafloor is pulled under into the mantle Guyot – Flat topped mountain underwater Seamount – underwater mountain Island – Where land rises up out of the water away from the continental plate

Labeling Exercize Get into groups of 2 or 3. Each group needs a blue ocean floor map, a dry erase marker, and paper towel to erase with.

Labeling Exercize Copy the map into your notes with labels. Quiz on this next class!

Mapping the Ocean Floor In groups of 3 or 4, get a shoe box, straw, and ruler. Inside the box, there is an unseen landscape you must map. Make a table with one column for the hole number, and 3 others for depth. Gently push your straw through each hole, place your thumb on the bottom where it stops, remove straw. Measure from thumb to the end of straw. This is your depth. Continue for all holes (3 times). Take the average of the 3 measurements and then make a graph. All group members must copy table and make their own graph. You will make a line graph. Remember, bottom line = be independent!

Mapping the Ocean Floor Imagine you are an oceanographer traveling across the Atlantic along the 45º N latitude line.  You and your crew are using sonar to gather data on the depth of the ocean between Nova Scotia, Canada, and the town of Soulac on the coast of France.  In this activity, you will plot depth data to create a profile of the ocean floor. Ocean Depth Sonar Data Longitude (º W) Ocean Depth (m) 64 60 91 55 132 50 73 48 3512 45 4024 40 3805 35 4171 33 3439 30 3073 28 1756 27 2195 25 3146 20 4244 15 4610 10 4976 05 4317 04 146 01 Lab Questions: Sonar ships send down beams of sound, which bounces off objects back to the ship. The time it takes for it to bounce off tells how deep the ocean floor is. Can you think of an animal that uses the same method to travel at night? Your graph contains parts of the ocean floor like the continental shelf, slope, rise, trenches, etc. Label any sea floor features you can see. You should find at least 11. Do you think sonar is a good way to study the ocean floor? Why?

Scientific Notation, The solution for big and small numbers Represents REALLY big and small numbers through powers of ten. Powers like 102, 103, 107 5 billion = 5,000,000,000 This has 9 places after the 5 In scientific notation, this is 5 x 109 0.000005 looks like 5 x 10-6 Small numbers get negative signs!

Scientific Notation Examples: Examples: 450000 = 4.5 x 105

Test Yourself 3,400 687,000 0.032 0.0000983 870,000,000 0.0000203 9,060,000 200 0.5 28,400,000,000

How did you do? 3,400 = 3.4 x 103 687,000 = 6.87 x 105 0.032 = 3.2 x 10-2 0.0000983 = 9.83 x 10-5 870,000,000 = 8.7 x 108 0.0000203 = 2.03 x 10-5 9,060,000 = 9.06 x 106 200 = 2 x 102 0.5 = 5 x 10-1 28,400,000,000 = 2.84 x 1010

Can you go backwards? 4.3 x 103 2.8 x 10-6 3 x 105 7.43 x 10-4

How did you do? 4.3 x 103 = 4,300 2.8 x 10-6 = 0.0000028 3 x 105 = 300,000 7.43 x 10-4 = 0.000743 9.2 x 108 = 920,000,000 5.23 x 10-2 = 0.0523 8.9 x 102 = 890

One more practice… 6.3 x 106 4530000 0.000098 2.45 x 10-5 7.8 x 10-7

One more practice… 6.3 x 106 = 6300000 4530000 = 4.53 x 106 0.000098 = 9.8 x 10-5 2.45 x 10-5 = 0.0000245 7.8 x 10-7 = 0.00000078

Quiz on SciNot Next Class!