CLASS COPY
Write all your answer in your notebook
CLASS COPY
PEANUT ALLERGIES??
PLEASE LET MS. DARWAZEH
KNOW- WE HAVE PLAIN M&M’S
FOR YOU TO USE
Earth’s Layers
Activity
Objectives Students will be able to:


Explain how the candy layers represent Earth’s
layers
Compare the texture of the crust and upper
mantle with the underlying mantle


Compare how the lithosphere and
aesthenosphere both fracture under pressure
Use data to determine the accuracy of a model
Key Points:
1. The lithosphere is composed of crust and upper
mantle
2. Crust and upper mantle fracture as a single unit, the
lithosphere
3. Broken pieces of lithosphere are called lithospheric
plates, or plates.
4. Aesthenosphere is hotter than lithosphere because
it is deeper in the earth.
5. When pressure is applied, aesthenosphere flows,
though it remains solid. This is called plastic
behavior and the hot rock has a plastic texture.
6. The boundary between the lithosphere and
aesthenosphere is somewhere near 100km where
the rock texture changes from rigid to plastic.
Detailed information
Since the 1960s we have learned much about the structure of the outer layers of the earth. We have determined that
the surface rock layer of the earth, the crust, is strongly coupled with the uppermost portion of the mantle and together
those layers comprise the lithosphere. Crustal material within the lithosphere may be either continental crust or
oceanic crust, depending on its origin, composition, and location. The lithosphere has a rigid texture and when it is
exposed to great pressure it fractures into pieces we refer to as lithospheric plates (or, plates). The reason the upper
mantle is included in the lithosphere is that it is colder and more rigid than the mantle beneath it, so that when stresses
occur at or near the earth’s surface, the upper mantle fractures the same way the crust fractures.
Below the lithosphere is the aesthenosphere, which lies completely within the mantle. Because the aesthenosphere is
deeper in the earth, it is much hotter than the lithosphere, and behaves differently to applied stresses. Even though the
aesthenosphere is solid, under pressure it has the ability to flow, referred to as plastic texture.
Therefore, when pressure is applied to the outer portions of the earth, the rigid lithosphere fractures into plates on top
of the plastic aesthenosphere. The movement of these plates is referred to as plate tectonics and the lithosphere and
aesthenosphere are considered tectonic layers of the earth. The surface of these plates, viewed on a map, includes
ocean floor and continental landmasses. Therefore, a continent is only part of a larger piece of lithosphere.
Below the aesthenosphere is the core. The core has a liquid outer core, made of molten iron, and a solid inner core, also
made of iron. Even though the inner core is hotter and more dense than any other layer, it is a solid because due to
being under an enormous amount of pressure.
Procedures and Questions
Copy underlined portions into your notebook. Complete all drawings and answer all questions in your
notebook.
1. Carefully bite the M&M so that you cut the M&M through the peanut center. (You may eat
the part you bite off!) Draw and color a cross-section (the cut-away section) of the M&M. Be sure to illustrate
the color coating, the white candy layer, the chocolate, and the peanut.
CLASS COPY
Write all your answer in your notebook
CLASS COPY
2. Observe how the color coating and white candy layers have fractured, particularly where you applied the
stress (where you bit into the candy). Did the color coating and white candy layers break together or did they
break as separate layers, on top of the chocolate?
3. This M&M is a miniature model of the earth. Which layers of the earth do the following parts of the M&M
represent?
a. color coating
b. white candy layer
c. color coating layer (crust) and white candy layer (upper mantle) together
d. chocolate
e. peanut
4. Label each of the layers on your diagram.
5. Describe what happens to the lithosphere when stresses (such as biting into the M&M) are applied.
6. Why is the upper mantle included as part of the lithosphere?
7. How does the lithosphere differ from the aesthenosphere in terms of texture?
8. Copy Table 2 (Earth and M&M Comparisons) into your notebook. Use the knowledge you have gained from
the model and Table 1 (Earth’s Structure) to complete Table 2.
Table 1. Earth’s Structure
Layer
Crust
Upper Mantle
Thickness (km)
30
720
Lower Mantle
Outer Core
Inner Core
Total:
2171
2259
1221
6401
State
Solid
Plastic
Plastic
Liquid
Solid
Main Composition
Granite, andesite, basalt
Peridotite
Magnesium and silicon
oxides.
Iron
Iron
Table 2. Earth and M&M Comparisons
M&M layers
Shell
Chocolate
Peanut
Total Thickness
Average
thickness
% of total
Corresponding layer
of the Earth
Thickness of Earth's
layer (km)
% total
thickness
0.6 mm
1.5 mm
9.0 mm
9. Why do we use models for Earth’s layers?
10. Which attributes of the Peanut M&M model are good representations of Earth’s internal structure? Use
the background information, your observations, and Table 2 to describe at least 2 attributes and explain
your answer using evidence.
11. How is this model NOT like Earth’s structure? Use the background information, your observations, and
Table 2 to describe at least 2 differences and explain your answer using evidence.
12. What other everyday objects or foods could you use as a model for Earth’s layers?