Laboratory Write-ups
Your Name: Sarah Helfrich
Laboratory Title: Edible layers of the Earth
Lab Objectives: Students will gain a better understanding on how the Earth is divided
into different layers. Students will know the name of the layers and in what order they
occur. Students will also learn the relative thickness of each layer and their composition.
Benchmark(s) Addressed:
CCG: The Dynamic Earth:
Understand changes occurring within the lithosphere, hydrosphere, and atmosphere
of the Earth.
SC.05.ES.03 Identify causes of Earth surface changes.
SC.05.ES.03.02 Identify effects of rapid changes on Earth's surface features
including earthquakes and volcanoes.
SC.08.ES.03 Describe the Earth's structure and how it changes over time.
SC.08.ES.03.01 Recognize the solid Earth is layered with a lithosphere, a hot
convecting mantle, and a dense metallic core.
SC.08.ES.03.02 Identify the processes that result in different kinds of landforms.
Materials and Costs:
List the equipment and non-consumable material and estimated cost of each
Item……………………………………………………………………………………Cost
Marshmallows (16oz bag)………………………….……………………………….. $2.00
Mints……………………………………….……………………..…………………..$0.99
Bakers Chocolate (8oz bar)…………………………………….……………………..$0.99
Toothpicks (750 count)…………………………………………………………...…..$1.17
Wax Paper……………………………………………………………………...……..$1.99
Plastic
Knifes……………………………………………………………………….…$0.99
Pot/ sauce pan……………………………………………………….……Bring from home
Heat Source (hot plate)……………………………………………………….……..$19.99
Estimated total, one-time, start-up cost:
$28.12
List the consumable supplies and estimated cost for presenting to a class of 30 students
Item
$
Marshmallows (16oz bag)………………………….……………………………….. $2.00
Mints……………………………………….……………………..…………………..$0.99
Bakers Chocolate (8oz bar)…………………………………….……………………..$0.99
Toothpicks (750 count)…………………………………………………………...…..$1.17
Wax Paper……………………………………………………………………...……..$1.99
Estimated total cost each year: $7.14
Procedure:

Each student will receive one of the fallowing: mint, marshmallow (may want to
provide vegan marshmallows), toothpick, piece of wax paper, and a plastic knife.

Step 1: Cut a notch into the marshmallow with plastic knife and insert mint. (the
core into the mantle)

Step 2: The student will attach the marshmallow/mint onto a toothpick

Step 3: Each student, with the guidance of adult or teacher, dip marshmallow into
melted chocolate to create the “crust”.

Edible Earth will need to cool and dry on wax paper for approx. 5-10 minutes
Time:
Initial prep time: Purchasing of items 20- 30 minutes
Preparation time: Melting chocolate, dividing/ organizing materials 25 minutes
Instruction time: Providing instruction and actual activity 30-40 minutes
Clean-up time: about 15 minutes
Assessment:
1-4 Label the four layers of the Earth.
1.Crust 2.Mantle 3.Outer Core 4. Inner Core
http://volcano.und.edu/vwdocs/vwlessons/lessons/Ch1CMA/Answer_Key_Test1.html
5. What is the Core made up of?
Inner: solid iron and nickel Outer: liquid iron and nickel
6. What is the difference between the inner mantle and the outer mantle?
Inner mantle is more plastic while the outer is more brittle.
7. Name the two types of crust found on the surface of the Earth.
The continental crust and the oceanic crust.
8. Name the four layers of the atmosphere in the correct order from the Earth to space.
Troposphere, Stratosphere, Mesosphere, Thermosphere
9. In what part of the atmosphere do we find weather balloons and spy planes?
The stratosphere
Background:
Core: The average density of Earth is 5515 kg/m3, making it the densest planet in the
Solar system. Since the average density of surface material is only around 3000 kg/m3,
we must conclude that denser materials exist within Earth's core. Further evidence for the
high density core comes from the study of seismology.
Seismic measurements show that the core is divided into two parts, a solid inner core
with a radius of ~1220 km and a liquid outer core extending beyond it to a radius of
~3400 km. The solid inner core was discovered in 1936 by Inge Lehmann and is
generally believed to be composed primarily of iron and some nickel.
In early stages of the Earth's formation about 4.5 billion (4.5×109) years ago, melting
would have caused denser substances to sink toward the center in a process called
planetary differentiation (see also the iron catastrophe), while less-dense materials would
have migrated to the crust. The core is thus believed to largely be composed of iron
(80%), along with nickel and one or more light elements, whereas other dense elements,
such as lead and uranium, either are too rare to be significant or tend to bind to lighter
elements and thus remain in the crust. Some have argued that the inner core may be in the
form of a single iron crystal.[3][4]
The liquid outer core surrounds the inner core and is believed to be composed of iron
mixed with nickel and trace amounts of lighter elements.
Recent speculation suggests that the innermost part of the core is enriched in gold,
platinum and other iron-loving elements.
It is generally believed that convection in the outer core, combined with stirring caused
by the Earth's rotation, gives rise to the Earth's magnetic field through a process described
by the dynamo theory. The solid inner core is too hot to hold a permanent magnetic field
but probably acts to stabilize the magnetic field generated by the liquid outer core.
Recent evidence has suggested that the inner core of Earth may rotate slightly faster than
the rest of the planet.[8] In August 2005 a team of geophysicists announced in the journal
Science that, according to their estimates, Earth's inner core rotates approximately 0.3 to
0.5 degrees per year relative to the rotation of the surface.[9][10]
The current scientific explanation for the Earth's temperature gradient is a combination of
the heat left over from the planet's initial formation, the decay of radioactive elements,
and the freezing of the inner core.
Mantle: Earth's mantle extends to a depth of 2890 km, making it the largest layer of the
Earth. The pressure, at the bottom of the mantle, is ~140 GPa (1.4 Matm). The mantle is
composed of silicate rocks that are rich in iron and magnesium relative to the overlying
crust. Although solid, the high temperatures within the mantle cause the silicate material
to be sufficiently ductile that it can flow on very long timescales. Convection of the
mantle is expressed at the surface through the motions of tectonic plates. The melting
point and viscosity of a substance depends on the pressure it is under. As there is intense
and increasing pressure as one travels deeper into the mantle, the lower part of the mantle
flows less easily than does the upper mantle (chemical changes within the mantle may
also be important). The viscosity of the mantle ranges between 1021 and 1024 Pa·s,
depending on depth.[11] In comparison, the viscosity of water is approximately 10-3 Pa·s
and that of pitch 107 Pa·s. Thus, the mantle flows very slowly.
Crust: The crust ranges from 5 to 70 km in depth. The thin parts are oceanic crust
composed of dense iron magnesium silicate rocks and underlie the ocean basins. The
thicker crust is continental crust, which is less dense and composed of sodium potassium
aluminum silicate rocks. The crust-mantle boundary occurs as two physically different
events. First, there is a discontinuity in the seismic velocity, which is known as the
Mohorovičić discontinuity or Moho. The cause of the Moho is thought to be a change in
rock composition from rocks containing plagioclase feldspar (above) to rocks that contain
no feldspars (below). Second, there is a chemical discontinuity between ultramafic
cumulates and tectonized harzburgites, which has been observed from deep parts of the
oceanic crust that have been abducted into the continental crust and preserved as
ophiolite sequences.
Troposphere: From the Greek word meaning to turn or change. The troposphere is the
lowest layer of the atmosphere; it begins at the surface and extends to between 7 km
(23,000 ft) at the poles and 17 km (60,000 ft) at the equator, with some variation due to
weather factors. The troposphere has a great deal of vertical mixing due to solar heating
at the surface. This heating warms air masses, which makes them less dense so they rise.
When an air mass rises the pressure upon it decreases so it expands, doing work against
the opposing pressure of the surrounding air. To do work is to expend energy, so the
temperature of the air mass decreases. As the temperature decreases, water vapor in the
air mass may condense or solidify, releasing latent heat that further uplifts the air mass.
This process determines the maximum rate of decline of temperature with height, called
the adiabatic lapse rate. It contains roughly 80% of the total mass of the atmosphere. 50%
of the total mass of the atmosphere is located in the lower 5 km of the troposphere.
The average temperature of the atmosphere at the surface of Earth is 15 °C (59 °F)
Stratosphere: From the Latin word "stratus" meaning a spreading out. The stratosphere
extends from the troposphere's 7 to 17 km (23,000 – 60,000 ft) range to about 50 km
(160,000 ft). Temperature increases with height. The stratosphere contains the ozone
layer, the part of the Earth's atmosphere which contains relatively high concentrations of
ozone. "Relatively high" means a few parts per million—much higher than the
concentrations in the lower atmosphere but still small compared to the main components
of the atmosphere. It is mainly located in the lower portion of the stratosphere from
approximately 15 to 35 km (50,000 – 115,000 ft) above Earth's surface, though the
thickness varies seasonally and geographically. Ozone Layer: The Earth's ozone layer
protects all life from the sun's harmful radiation, but human activities have damaged this
shield. Less protection from ultraviolet light will, over time, lead to higher skin cancer
and cataract rates and crop damage. The U.S., in cooperation with over 160 other
countries, is phasing out the production of ozone-depleting substances in an effort to
safeguard the ozone layer.
Mesosphere: From the Greek words meaning middle. The mesosphere extends from
about 50 km (160,000 ft) to the range of 80 to 85 km (265,000 – 285,000 ft), temperature
decreasing with height. This is also where most meteors burn up when entering the
atmosphere.
Thermosphere: From 80 – 85 km (265,000 – 285,000 ft) to 640+ km (400+ mi),
temperature increasing with height. The thermosphere is the layer of the earth's
atmosphere directly above the mesosphere and directly below the exosphere. Within this
layer, ultraviolet radiation causes ionization. The thermosphere, named from the Greek
(thermos) for heat, begins about 80 km above the earth. At these high altitudes, the
residual atmospheric gases sort into strata according to molecular mass. Thermospheric
temperatures increase with altitude due to absorption of highly energetic solar radiation
by the small amount of residual oxygen still present. Temperatures are highly dependent
on solar activity, and can rise to 15,000°C. Radiation causes the atmosphere particles in
this layer to become electrically charged (see ionosphere), enabling radio waves to
bounce off and be received beyond the horizon. At the exosphere, beginning at 500 to
2,000 km above the earth's surface, the atmosphere mixes into space.
The few particles of gas in this area can reach 2,500°C (4532°F) during the day. Even
though the temperature is so high, one would not feel warm in the thermosphere, because
it is so near vacuum that there is not enough contact with the few atoms of gas to transfer
much heat. A normal thermometer would read significantly below 0°C.
The upper region of this atmospheric layer is called the ionosphere.
The dynamics of the lower thermosphere (below about 120 km) are dominated by
atmospheric tide, which is driven, in part, by the very significant diurnal heating. The
atmospheric tide dissipates above this level since molecular concentrations do not support
the coherent motion needed for fluid flow.
Exosphere: From 500 – 1000 km (300 – 600 mi) up to 10,000 km (6,000 mi), freemoving particles that may migrate into and out of the magnetosphere or the solar wind.
The exosphere is the uppermost layer of the atmosphere. On Earth, its lower boundary at
the edge of the thermosphere is estimated to be 500 km to 1000 km above the Earth's
surface, and its upper boundary at about 10,000 km. It is only from the exosphere that
atmospheric gases, atoms, and molecules can, to any appreciable extent, escape into
space. The main gases within the exosphere are the lightest gases, mainly hydrogen, with
some helium, carbon dioxide, and atomic oxygen near the exobase. The exosphere is the
last layer before space.