1. Journey to the Center of the Earth creation of our planet

2. Layers of the Earth pg. 10 in ESRT
How and why did the earth come to be separated into layers?

3. Creation of the Earth and her layers
Earth formed about 4.6 billion years ago due to accretion (collisions) of gases and planetary “dust” after the solar nebula collapse ~5 billion years ago
As the mass of Earth ↑ so did its gravitational pull
Gravity has caused Earth & other planets over time to become “layered” according to differences in the density of it’s materials
Creation of the Earth and her layers

4. Journey to the center science fiction or fact?
If we were to “drive” (65 mph thruway style) to the center of the earth how long would it take? (neglecting the effects of changing gravity and acceleration)
1.) Atmosphere- 12 hrs
2.) Biosphere- 20 sec
3.) Crust- 30 min
lithosphere
4.) Asthenosphere +Mantle- 29 hours
5.) Outer Core- 22 hours
6.) Inner core- 13 hours
That’s over 3 days!

5. The Crust- mostly Silicon & Oxygen
Outer layer
5-100 km thick
2 types:
Oceanic :Basalt, d=3.0 g/cm³
~8 km thick on average
Continental: less dense, made of granite, 2.7g/cm³
32 (km) thick on average

6. How do we know what the crust is made of?
Mines/drill holes reach down to 12 (km)
Provide direct evidence by rock samples
But this is only 1/10th of 1% of earth’s diameter
Earthquake (seismic) waves provide evidence for the earth’s composition much like x-rays provide evidence for what the human insides look like

7. The Mantle (“Middle) Very thick
The upper portion (top) belongs to the lithosphere (stiffer)
The asthenosphere lies underneath where the mantle becomes ductile like “plastic” rock due to High P and sharp increase in T (pg. 10 ESRT)
The “Moho” is the boundary between the crust and mantle
Mantle extends to 2900 (km) into the earth- made of olivine and pyroxene (dark minerals)

8. How do we know what the mantle is made of?
1.)The average density of earth
is ~5.5 g/cm3, yet crustal rocks have a relative density ~3 g/cm3indicates denser material at center!
2.)Seismic waves travel faster in the mantle than the crust (means we’ve encountered different material).
3.)Magmas which come out of the earth contain high amounts of dense minerals
4.)Meteorites from space contain large amounts of these minerals (remember, our planet originally formed from accreted material)

9. The Core- made of mostly iron (Fe) and some nickel (Ni)
The outer core: thought to be liquid
The inner core: thought to be solid
~1/3 of all earth’s mass
-Composition is also inferred from meteorite samples
-scientists think logically that the densest materials “sank”
to the center

10. If the inside of the core is assumed to be as hot as the surface of the sun (5500 C) how could it be solid?

11. Page 10 of your ESRT gives you information on:
1.) the layers in order with their densities
2.)How pressure changes as you go deeper into the earth
3.)How temperature changes as you go deeper into the earth

12. Activities this week
1.) Make a pie graphs of Earth’s Spheres/Chemical composition worksheet
2.)Complete the “Layers of the Earth” Note-page in PENCIL using page 1 and 10 of your ESRT. (You will need a Calculator)
3.) Clay Balls Inquiry Activity
4.) Scale Model of the Earth (lab)

13. Layers of our Atmosphere

14. The Atmosphere There are 4 layers in the atmosphere; *Troposphere
Stratosphere
Mesosphere
Thermosphere
*All layers end in
“sphere”
The names of the boundaries between the layers end in “pause” ex: Tropopause is the boundary between the troposphere and mesosphere

15. What variable “Defines” each layer based upon what you see in the diagram?

16. General relationships of the atmosphere
Each layer becomes less and less dense with ↑ altitude (height) as atmospheric pressure ↓
The troposphere, the thinnest layer (~12 km) contains 99% of all of the water vapor in the atmosphere and is 80% of the atm’s total mass
Temp. ↑ in the stratosphere due to the presence of the ozone layer which absorbs UV radiation from the sun