Download station 1 earth`s layers

Structure of the Earth System
Station 1 – Earth’s Layers
At this station, you will learn about the layers of the Earth. There are multiple layers of the
Earth. The Earth layers are: the crust, the mantle, the outer core, and the inner core. Some of
the layers are considered to parts of the lithosphere and others are part of the asthenosphere.
Each layer has its own properties, make-up, and characteristics. The crust comprises the
continents and ocean basins. It has a variable thickness, anywhere from 35-70 km thick in the
continents and 5-10 km thick in the ocean basins. Just under the crust is the mantle. It is
composed mainly of ferro-magnesium silicates. It is about 2900 km thick, and is separated into
the upper and lower mantle. This is where most of the internal heat of the Earth is located.
Large convective cells in the mantle circulate heat and may drive plate tectonic processes.
There are two very distinct parts of the core: the outer and the inner core. The outer core is
2300 km thick and the inner core is 1200 km thick. The outer core is composed mainly of a
nickel-iron alloy, while the inner core is almost entirely composed of iron. The outer core
contains as much as 10% lighter elements than iron alloy. The inner core is thought to rotate at
a different speed than the rest of the Earth and this is thought to contribute to the presence of
the Earth’s magnetic field.
Activity 1
A. Define these vocabulary Words on the vocabulary sheet for this station: crust, mantle,
core, lithosphere, convection currents
Activity 2
Go to the site: http://volcano.oregonstate.edu/earths-layers-lesson-1 Read through the
lesson on Earth’s layers then answer the following questions.
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Name the four layers of the Earth in order from the outside to the center of the Earth.
How thick is each layer of the Earth?
What causes the mantle to "flow"?
What are the two main metals that make up the outer and inner core?
Explain the importance of convection currents.
Describe in your own words how the Earth's layers were formed.
Activity 3
Convection Currents Experiment
1. You will use the sink in the back of the room for this activity!
2. Fill two bottles with warm water from the tap and the other two bottles with cold water. Use
food coloring to color the warm water yellow and the cold water blue. Each bottle must be filled
to the brim with water.
3. Hot over cold: Place the index card or old playing card over the mouth of one of the warm
water bottles. Hold the card in place as you turn the bottle upside down and rest it on top of one
of the cold water bottles. The bottles should be positioned so that they are mouth to mouth with
the card separating the two liquids. Carefully slip the card out from in between the two bottles.
Make sure that you are holding onto the top bottle when you remove the card. Observe what
happens to the colored liquids in the two bottles. Write your observations.
4. Cold over hot: Repeat steps 2 and 3, but this time, place the bottle of cold water on top of the
warm water. Observe what happens. Write your observations.
The explanation behind convection currents
Hot air balloons rise because warm air is lighter than cold air. Similarly, warm water is lighter in
weight or less dense than cold water. When the bottle of warm water is placed on top of the cold
water, the more dense cold water stays in the bottom bottle and the less dense warm water is
confined to the top bottle. However, when the cold water bottle rests on top of the warm water,
the less dense warm water rises to the top bottle and the cold water sinks. The movement of
water is clearly seen as the yellow and blue food coloring mix, creating a green liquid. The
movement of warm and cold water inside the bottles (or tank) is referred to as the convection
current. In our daily life, warm currents can occur in oceans, like the warm Gulf Stream moving
up north along the American Eastern Seaboard. Convection currents in the atmosphere are
responsible for the formation of thunderstorms as the warm and cold air masses collide.