1. Notes: Earth/Moon Formation 3/11

2. 1.Explain the three sources of heat that contributed to the high temperature of the newly formed Earth. (p. 688). The three sources of heat were Energy from the planetesimals that collided Increasing weight of outer layers compressed inner layers Radioactive materials

3. #2. What is the process of differentiation? #2. It is when denser materials, like molten iron, sank to Earth’s center and less dense materials were forced to outer layers, causing 3 distinct layers.

4. #3. What elements make up the Earth’s core? Mantle? Crust? The dense core is made of iron and nickel. The mantle is made of iron and magnesium-rich rock. The crust is less dense, silica-rich rock.

5. #4. Why is the core of the Earth more dense than the crust? What does this have to do with differentiation? The Earth was hot enough to melt iron. The dense, molten iron sank to the center of the Earth. The less dense elements were forced to outer surface. This is called differentiation.

6. #5. How do scientists know the inner core is solid and the outer core is liquid? (p. 298) They measure P and S waves (seismic waves) and see the Shadow Zones caused by the liquid outer core and solid inner core. #6. What is a crater? A crater is a bowl-shaped depression. #7. How is a crater formed? A crater is formed when debris left over from the formation of the solar system hits the surface of the moon or planet.

7. #8. How does the composition of moon rocks compare to the composition of the rocks found on Earth? Moon rocks contain the same elements in different proportions. Lunar rocks are igneous, contain mostly O and Si. Highland rocks are rich in Ca and Al, maria rocks contain Ti, Mg, and Fe.

8. #9. How do scientists know about the interior layering of the moon? Seismographs have recorded moonquakes. #10. How is the interior layering of the moon similar to that of Earth? Different? They are similar because the moon also has a crust, mantle and core. The core is both liquid and solid. They are different because the crust is thicker on one side.

9. #11. What is the most accepted hypothesis for the formation of the moon? The Giant Impact Hypothesis is the most accepted hypothesis. It states that a Mars-sized body hit Earth, which ejected chunks of Earth’s mantle into orbit around the Earth. The debris came together to form the moon.