Science Chapter 7
the soft layer of the mantle on which the tectonic plates move
asthenosphere
A substance composed of two or more elements is a(n)
compund
What are the two kinds of crust that a tectonic plate may contain?
continental crust and oceanic crust
List the three layers of the Earth, based on their chemical composition.
crust, mantle,and the core
the solid layer of the core
inner core
What element makes up most of the Earth's core?
iron
Oceanic crust is denser than the continental crust because it contains more of which three elements?
iron calcium magnesium
Will a seismic wave traveling through a solid go faster or slower than a seismic wave traveling through liquid?
it would travel slower in a liquid because the liquid would absorb it.
The Earth is composed of several
layers
the solid, outer layer of the earth that consist of the crust and the rigid upper part of the mantle.
lithosphere
The mantle is composed of more of the element______than the crust is.
magnesium
the strong, lower part of the mantle between the asthenoshpere and the outer core
mesosphere
the liquid layer of the core
outer core
What three elements make up most of the Earth's crust?
oxygen silicone aluminum.
What do scientists use to study Earth's interior?
seismic waves
The mantle has less aluminum and less __________ than the crust does.
silicone
Large pieces of the lithosphere that move around on the asthenosphere are called
tectonic plates
List three ways in which tectonic plates floating on the asthenosphere are similar to ice cubes filling a punch bowl.
tectonic plates float on the mantle like ice float on water
Why are tectonic plates like the pieces of a jigsaw puzzle?
the pieces fit together in different shapes and sizes
What are seismic waves?
vibrations from a seismograph
How much of the Earth's mass is made up by the core?
33%
Why do less dense compounds make up Earth's crust while the densest compounds make up the core?
The less dense compounds float on the top of the mantle and the more dense sink in the middle of the earth.
Why do scientists look to the ocean floor to research the mantle?
Why do scientists look to the ocean floor to research the mantle?