Answer to Question 1ANS:Answer
should include:
The crust is the outermost layer. It is thin and lightweight. The crust is 1 of the volume
and 0.4 of the mass of Earth. There are two types of crust: oceanic and continental.
The oceanic crust is composed of mostly basalt. This type of crust is dark colored, heavy
and thin. It is denser than the continental crust and contains oxygen, silicon, magnesium,
and iron.
The continental crust is made of granite. This is a thick, light colored rock. Continental
crust contains oxygen, silicon, and aluminum.
The mantle is the largest layer in terms of mass (68) and volume (83). It is the layer
beneath the crust and is thought to be made of silicon and oxygen with some iron and
magnesium.
The composition of the mantle has not been determined by direct sampling. Information
on the composition of the mantle has come from the analysis of earthquake shocks,
volcanic gases that have been released, and variations in the pull of gravity.
The core is the innermost layer of the Earth. It is mainly iron and nickel, but also
contains silicon, sulfur, and other heavy metals. This is the thickest layer at 3,470
kilometers.
Information on the core has come from studying the behavior of body waves through the
interior of the Earth.
Answer to Question 2ANS: F
Two types of body waves are used to determine the Earth's interiorprimary and secondary waves.
Surface waves undulate along the surface so they are not useful in determining the Earth's interior
structures. Information can be found in the section The Study of Earthquakes Provides Evidence of
Layering.
An example of layers, or strata, of sedimentary rock that contain fossils
Formation of germ layers.
Photomicro graph showing the three layers of the skin.
Distribution of Earth's Water
Relative Sizes of Dwarf Planets and Earth
Earth 65 Million Years Ago