Earth’s Structure and Density Review
Indicator
a. Compare the densities of Earth's
atmosphere, water, crust, and
interior layers.

Main Ideas/ILOS
Earth’s atmosphere is least dense,
followed by water, crust, mantle,
outer core then inner core.
b. Relate density to the relative
positioning of Earth’s
atmosphere, water, crust, and
interior.

Earth’s layers are in their current
position because early in Earth’s
formation, denser materials could
move, based on their densities.
c. Model the layering of Earth's
atmosphere, water, crust, and
interior due to density
differences.

A correct model of Earth would use
the least dense substances on the
outside (atmosphere) and become
more dense toward the inner core.
d. Distinguish between models of
Earth with accurate and
inaccurate attributes.

Many models of Earth exaggerate
the size of surface features such as
mountains. If Earth were shrunk to
globe size, it would be very smooth.
Which answer shows the following items in order from the highest density to the lowest density?
a. water, atmosphere, core, crust
b. atmosphere, crust, core, water
c. crust, water, atmosphere, core
d. core, crust, water, atmosphere
Why is air less dense than Earths rocks?
a.
The molecules in rock are larger than the molecules in air.
b.
The molecules in rock are smaller than the molecules in air.
c.
The molecules in air are further apart than in rocks.
d.
The molecules in air are closer together than in rocks.
Ryan is given the following items: a rock, sand, water, and metal bar. Ryan calculates the density of each object . The
results are as follows: Rock = 3.2 g/mL, Sand = 1.9 g/mL, Water = 1.0g/mL, Piece of metal = 6.5 g/mL . Ryan then puts
all of the items into a jar and shakes it up. He lets the jar settle for 5 minutes. What would be the expected order of the
items going from the top of the container to the bottom?
a. rock, sand, water, metal
c. water, sand, rock, metal
b. metal, rock, sand, water
d. sand, metal, water, rock
If the core of the earth is so hot, explain why it is a solid, not a gas. _____________________________
______________________________________________________________________________________
How has technology influenced our discoveries of the structure of the earth?
a. Satellite technology has allowed us to see what is inside the earth
b. Infrared (heat sensing) technology has allowed us to measure the temperature of the earth
c. X-Ray technology has allowed us to see the rock layers within the earth
d. Seismograph (earthquake sensing) technology has allowed us to calculate the thickness and density of the
layers within the earth.
You are given an unknown object. You find its mass to be 28g. You find its volume to be 10 mL. Using the chart below,
answer the following questions:
Layer
Water
Crust
Mantle
Outer Core
Inner Core
Approximate Density
0.10 g/mL
2.7 – 3.0 g/mL
3.3 – 5.7 g/mL
9.0-12.0 g/mL
12.7 – 13.0 g/mL
What is the density of the object? _________
What layer of the earth would this object most likely have come from? _____________________________
The mantle is a layer of Earth. What is its density as compared to other layers?
a. Most dense than all the other layers
b. More dense than the crust, less dense than the core
c. Less dense than the crust, more dense than the core
d. The same as both the crust and the core.
Which of the following statements best explains why road cuts are often layered:
a. Things in nature like to order themselves by color, dark things to the bottom and light things on top.
b. Things in nature like to order themselves by density, most dense to the bottom and least dense on top.
c. Things in nature like to order themselves by particle size, largest particles to the bottom and smallest articles
to the top.
d. Things in nature like to order themselves by temperature, hottest to the bottom and coolest to the top.
Why are iron and nickel found in Earth’s core?
a. They have a higher density than most of Earth’s substances.
b. They have a lower density than most of Earth’s substances.
c. The core is hotter than the other layers of the earth.
d. The core is colder than the other layers of the earth.
A beach is composed of particles of sand of the same size. Why doesn’t the beach have materials of
all sizes? The particles have
a. come from the same place.
b. come to the beach at the same time.
c. been found in underwater canyons.
d. been sorted by size and density.
Why does the atmosphere float above the crust?
a. the density of air increases when clouds form
c. air is more dense than the crust
b. air is less dense than the crust
d. air has the same density as the crust
A streambed contains round rocks, all about the same size. Why are there no smaller particles of
sand and clay? Sand and clay
a. are denser.
b. have washed away.
c. were never there.
d. are too small to see.
You are given the following materials and their densities and then asked to construct a model of the earth consisting of a
core, mantle, crust, water, and air.
Cotton
0.2 g/mL
Glue
1.0 g/mL
clay
1.8 g/mL
Aluminum foil
2.4 g/mL
A Quarter
4.6 g/mL
Based on density, which material would be the best choice to represent
the core of the Earth?
a. cotton
b. clay
c. aluminum foil
d. quarter
Based on density, which material would be the best choice to represent
the crust of the Earth?
a. cotton
b. clay
c. aluminum foil
d. quarter
Is this a good model of the earth or not? _________________
Give two reasons to support your inference.
a. ____________________________________________
b. ____________________________________________
How are the materials making up the core different from those of the crust?
a. they are harder
b. they are more colorful
c. they will dissolve in water
d. they are more dense
Where would the smallest particles of rock be found in a streambed?
a. In the strongest current
b. In the weakest current
c. Near the middle
d. At the beginning
A lake study reveals larger particles near the mouth of an incoming stream and smaller ones in the center of
the lake. What inference can be made from these observations?
a. The particles are being sorted by size.
b. The particles are made of different materials.
c. The particles are different densities.
d. The particles are traveling at different speeds.
Sand with particles of the same size was gently shaken in a jar to see if layers would form. What variable
was being tested?
a. particle size
b. particle density
c. particle color d. particle type
A student was given an assignment to calculate the density of a rock. Which of the following would best
describe one of the needed steps to calculating the rock’s density?
a. The student puts the rock in an empty graduated cylinder and records the measurement in milliliters.
b. The student puts the rock in a graduated cylinder filled with water and records the volume of the rock.
c. The student uses a thermometer to measure the temperature of the rock in Celsius degrees.
d. The student measures the length of the rock in centimeters with a metric ruler.
Which of the following will be carried farthest downstream after a mudslide?
a. sand
b. leaves
c. pebbles
d. rocks
Water is added to a jar with soil in it and the jar is shaken. Which drawing shows what will happen after it
sits for a few minutes?
a.
b.
c.
d.
How does density affect the organization of Earth?
a. The densest material is closest to the center.
c. The densest material is near the center.
b. The density material is farthest from the center.
d. Density differences allow materials to mix freely.
Earths rigid crust floats on the hot, plastic material of the mantle. What conclusion should be made about their density?
The crust is
a. denser and it floats
b. denser and it sinks
c. less dense and floats
d. same density as the mantle
Which model of Earth shows the most accurate shape and relative size of the continents?
a. a road map
b. a topographical map
c. a globe
d. a poster
Where is the most dense layer of the atmosphere located?
a. the greatest distance from the center of the earth
b. the least distance from the center of the earth
c. above the mountain regions
d. the atmosphere does not have layers
Why have scientists concluded that the core of the earth is a solid?
a. Mathematics show that the temperature is so high that it must be a solid.
b. X-rays cannot penetrate the core, so it must be a solid.
c. Seismic waves bounce off of the core, so it must be a solid.
d. Satellite images taken of the core show that it is a solid.
Why are relief globes such as this one inaccurate?
a. The continents are out of proportion.
b. The mountains are too tall compared to the
circumference of the earth.
c. The tectonic plates are not shown.
d. Looks good to me!
How will future improvements to technology most likely affect our model of the earth?
a. Scientists created our current model of the earth, therefore it will always be correct.
b. Scientists will supply only details that support the current model of the earth.
c. Scientists will disprove the ideas currently accepted to be true.
d. Scientists will observe more details that may change the current model.
A student is conducting Internet research about Bear Lake, and comes across the following statements in a news article.
Which of the following is an inference, not necessarily a fact?
a. Large rocks are located at the area where the river drains into the lake.
b. Bear Lake is the Caribbean of the Rockies.
c. Silt particles make up the layer of sediment nearest the water.
d. Larger particles of sand sink in the cold water before smaller particles of sand.
An unknown piece of rock sinks in water but floats in salt water. What do you know about the density of the rock?
a. It is more dense than water but less dense than salt water.
b. It is less dense than water and less dense than salt water
c. It is denser than water and denser than salt water.
d. It is less dense than water but more dense than salt water.
Three liquids are placed in a jar, and they form definite layers, which layer would represent the atmosphere if
the jar was used as a model of the earth?
a. the layer on the top
b. the layer on the bottom
c. the layer in the middle
d. not enough information has been given