1. • Sun’s ignition clears the solar system
• Fewer collisions
• Earth surface begins to cool
• Layers form as Earth cools
In your group,
investigate this claim

2. How is this evidence for layering?
Claim: Layer composition
by density
• Earth’s size and mass (determined by the 19th century) yield a planetary density of 5.5 g/cm³
• Later measurements determine the crust density is 2.8 g/cm3
How is this evidence for layering?

3. Claim: Layer composition
by most abundant elements
Mantle - Mg, Si
Mass
a.m.u.
Density
g/cm3 Si 14
2.33 O 16
.001 Mg 24
1.74 Fe 26
7.87 Ni 28
8.9
Core - Fe, Ni
Crust - O, Si
Evidence: What can mass, density, of Earth elements suggest about the formation of layers?

4. Claim: Layer composition
by compound
MgO, SiO2
Density
g/cm3
MgO
3.58
SiO2
2.65
Core – NiFe (alloy)
Crust - SiO2
Evidence via Density

5. Evidence: ranking of the 4 elements in each layer
Claim: Layer composition
by percent abundance
O, Si, Mg, Fe
Evidence: ranking of the 4 elements in each layer

6. Evidence: compounds per layer
Claim: Layer composition
By percent abundance
Mantle
Crust
Evidence: compounds per layer

7. Evidence: summarized Reasoning? in between
more massive elements, most dense,
least massive elements, least dense
Reasoning?