Download Formation of the Earth

OBJECTIVE: Describe the formation of
the solid Earth.
• INTRO:
– What do you think the Earth looked like the first
billion years of its existence?
Formation of the Earth
• Effects of Gravity & Heat
• Formed within 10 million
years of the collapse of
the solar nebula
• Grew from the collision of
planetismals
• Collisions generated heat
– Melted rock
– Volcanoes and Earthquakes
release the heat trapped
within
Formation of the Earth
• Layers of the Earth
• Crust
– Made of rocks and
materials low in density
• Mantle
– Made of materials that
are denser than the
crust
• Core
– Made of nickel and iron
which is the densest
Formation of the Earth
• Formation of Earth’s
Atmosphere
• Early Atmosphere
– Earth was HOT and had
large amounts of
poisonous gases, carbon
dioxide and water vapor
• Changing Atmosphere
– As Earth cooled, the
water vapor condensed
to create the first oceans
Formation of the Earth
• Role of Life
• First life forms in the
ocean
• Bacteria are the first
life-forms to develop
• They were simple
(unicellular) and did not
need oxygen
Formation of the Earth
• Source of Oxygen
• Organisms that first
began to do
photosynthesis began to
create an oxygen-rich
atmosphere
– Photosynthesis: Uses light
to convert carbon dioxide
to oxygen
• Over the next billions of
years, Earth’s atmosphere
filled up with oxygen
Formation of the Earth
• Formation of Oceans &
Continents
• Oceans
– After a few million years,
Earth was cool enough for
it to rain
– Water began to cover the
Earth and create the first
oceans
• Continents
– Heavier denser materials
sank into the Earth
– Lighter rocks and materials
piled up to create our
continents
Formation of the Earth
• Why Life is on Earth
• Liquid water
– Earth is not too hot or cold
to freeze or vaporize water
• Gravity
– Holds us down, but helps
create an atmosphere
• Gases
– Photosynthesis and
respiration help cycle
carbon dioxide and oxygen
• Magnetic Field
– Blocks harmful radiation
OBJECTIVE: Describe the formation of
solid Earth.
• OUTRO:
– Why did the Earth separate into distinct layers?