Transcript Earth - Wwrsd.org

Earth
What do you think it means when people
say the Earth is like an onion?
– Think! Think of an answer and write it in your
notes.
– Pair! Turn to the person next to you and share
your ideas.
– Share! Share your partner’s idea with the class.
The Earth is like an onion because it
contains many layers!
• The atmosphere – a thin
layer of air that surrounds
the Earth
• The hydrosphere – all water
and ice that covers the Earth
• The lithosphere – the crust
(land) that covers the Earth.
• Crust
– What we live on.
– Made up of minerals that
contain oxygen, silicon, and
smaller amounts of other
elements.
• Mantle
– liquid that the crust floats
on.
– Moves the continents,
causes earthquakes and
volcanic eruptions, and
forms mountains.
• Outer Core – liquid made
of iron and nickel
• Inner Core – solid
The Lithosphere
The Hydrosphere
• Earth is the only planet with abundant liquid
water on the surface.
• Water is essential for life on Earth.
• About 71% of the Earth is covered in water,
most of which is in the oceans.
– Only about 3% of Earth’s water is safe to drink!
The Atmosphere
• The air that surrounds Earth
• Protects us from small debris from space.
• Made up of:
– Nitrogen (78%)
– Oxygen (21%)
– Other gases (1%)
– Also contains water vapor, carbon dioxide, water
droplets, dust, and chemicals released from
volcanoes, fires, and human activities.
• Troposphere
– Closest to Earth’s surface
– Where weather occurs
• Stratosphere
– Ozone layer helps absorb
harmful ultraviolet
radiation from the Sun
• Mesosphere
• Thermosphere
• The atmosphere traps
heat from the Sun to
warm the Earth. This is
called the greenhouse
effect and is necessary for
life on Earth.
Atmospheric
Layers
Magnetic Field
• The area that surrounds a magnet.
• Earth has one as if there were a giant bar
magnet buried inside it.
• Currents of magma moving inside the core are
thought to create these magnetic fields.
• A compass will always point North because the
needle in the compass is
attracted to the North
magnetic pole.
Van Allen radiation belt
• Discovered by the American satellite, Explorer 1
• Acts like a shield, protecting us from particles
from the Sun. Held in place by Earth’s magnetic
field.
How does Earth compare to the other
planets?
What is wrong with this picture?
(Answer this on your notes sheet. Think about the lab we did on
Friday and compare it to this picture.)
How does Earth compare to the other
planets?
Is this picture more accurate? Why or why not?
How does Earth compare to the other
planets?
This is an accurate comparison of the rocky
inner planets and the dwarf planet Pluto.
How does Earth compare to the other
planets?
Remember how big Earth looked in the previous
picture? This is a picture of the inner planets
compared to the outer planets.
How do you think the size of the planets
compares with the size of the Sun?
Could there be other planets like Earth?
• For life to exist on another planet, what do
conditions on that planet need to be like?
• Any star in any galaxy could have planets
revolving around it…how do we figure out if
these planets can support life?
Searching for life
around other stars
http://ed.ted.com/lessons/a-needle-incountless-haystacks-finding-habitable-planetsariel-anbar
Kepler-22B
http://lightyears.blogs.cnn.com/2011/12/05/fi
rst-planet-in-habitable-zone-discovered/