Earth Formation
1. Starts as a nebula
2. Nebula begins to shrink in and spin creating an accretion disk.
3. Material collects in middle creating a proto sun.
4. Remaining material coalesce and become planetesimals.
5. Coalescing continues and forms protoplanets.
6. Solar System Forms
If the original mass of a radioactive parent material was 24 grams, how many grams of the parent material are left at the end of the third half-life?
3 grams
Name 3 Earth Layers by compositon.
Core, Mantle, Crust
What are 3 plate boundaries?
Convergent, Divergent and Transform-Fault
What is the creation of the Solar System called.
The Nebular Theory
What event(s) led to the earth being molten?
Radioactive decay, constant bombardment, increasing pressure in core.
How long does it take a 100.00g sample of As-81 to decay to 6.25g?
4HLs
Name 5 Earth layers by structure.
Lithosphere, Asthenosphere, Mesosphere, Outer Core, Inner Core
What evidence has helped prove the idea of continental drift? (5 things)
Fossils, Mountain ranges, clacial marking, coal deposits, rock layers.
How does the sun "turn on?"
Nuclear fusion, H bonds with H to form He.
In 4 steps, list how to moon formed.
1. A mars sized object collides with Earth.
2. Earth materials are flung into Earth's orbit.
3. The materials coalesce.
4. The moon is formed.
If a substance has a half-life of 4 years, how long will it take for a 64 g sample to decay to 8 g?
12 years
34 --> 8g = 3HLs
4*3 = 12 years
Asthenosphere
Describe the role of convection in seafloor spreading and plate movement.
Sea floor spreading is two divergent ocean plates moving away from each other. Because of this, convection that occurs in the mantle will send up magma which will form new ocean floor, or the rock basalt.
Which Earth layer is a liquid? Because it is a liquid what does it do for the Earth?
The outer core is a liquid. The churning of the liquid of iron and nickel is where Earth's magnetic field comes from.
Describe the Iron Catastrophe. What rose and what sank?
As Earth began to cool, heavy materials like iron and nickel sank, forming Earth's core. Lighter materials like silicates and oxygen rose to the top and formed Earth's crust.
The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7.2 minutes has elapsed?
12.5g remaining
7.2 / 2.4 = 3 half-lives
(1/2)3 = 0.125 (the amount remaining after 3 half-lives)
100.0 g x 0.125 = 12.5 g remaining
What isostacy?
Where the crust "floats" at an elevation determined by its thickness and density. Lighter crustal rocks float on denser, plastic-like mantle material.
What is the difference between an island chain created over a hot spot to those found in island arc?
Hot spot island chains form in the middle of tectonic plates from stationary mantle plumes, linear trails (e.g., Hawaii). Island arcs form at convergent boundaries where one plate subducts under another, creating curved chains of volcanoes that are generally similar in age.
Where does convection take place within the interior of Earth?
Earth's iron and nickel core created this? Why is it important to life on Earth?
What is the half-life of a 100.0g sample of nitrogen-16 that decays to 12.5 grams in 21.6 seconds?
7.2 seconds
100g --> 12.5g = 3HLs
21.6/3 = 7.2 seconds
What is Mohorovicic Discontinuity?
Compositional boundary separating the bottom of the lithosphere from the asthenosphere.
How does paleomagnetism data determine the rate of seafloor spreading?
By analyzing symmetrical, alternating magnetic "stripes" of normal and reversed polarity in basaltic ocean crust.
What determines whether a plate undgoes subduction?
The density of the plate, oceanic crust is more dense, therefore, it will undergo subduction.