Archimedes and Icebergs
Consider the example of an iceberg floating in the ocean.
 density of seawater =1025 kg/cubic meter
 density of ice =920kg/cubic meter
 since density of water > density of ice, ice floats
But exactly what percentage is submerged? How much of the iceberg floats
above the surface of the water? Calculate these values using the equation
below.
Density of Object
Density of Fluid
x 100% = % Submerged
Practice Problems: Archimedes, Isostacy, and Crustal Comparisons
Density of Continental Crust = 2.7 g/cm3
Density of Oceanic Crust = 3.0 g/cm3
Density of the Asthenosphere is 3.3 g/cm3
1. What percentage of continental crust is submerged in the
asthenosphere?
2. What percentage of continental crust floats above the asthenosphere?
3. What percentage of oceanic crust is submerged in the asthenosphere?
4. What percentage of oceanic crust floats above the asthenosphere?
5. Which floats higher in the asthenosphere, continental or oceanic crust?
Explain/support your answer!
Additional Challenge:
6. If a block of oceanic crust is 50 km thick, what thickness (in km) would
float above the asthenosphere? What if it were 35 km thick?
7. If a block of oceanic crust is 50 km thick, what thickness (in km) would
float above the asthenosphere? What if it were 35 km thick?
8. If a block of oceanic crust and a block of continental crust were both
the exact same thickness (85 km), which would float higher and by
how many km?