© Boardworks Ltd 20091 of 6 mesosphere thermosphere.
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Transcript of © Boardworks Ltd 20091 of 6 mesosphere thermosphere.
© Boardworks Ltd 20091 of 6
mesosphere
thermosphere
The Atmosphere Mixture of gases that surround Earth There are 4 layers in the atmosphere that
are divided based on their temperature gradient. troposphere, stratosphere mesosphere, thermosphere
4 Layers1) Troposphere – layer in which
we live; Weather phenomena (clouds) occur here. It’s elevation ranges from 0 to 10 km
2) Stratosphere – above troposphere; temperatures increase with altitude. This layer contains the ozone layer, which
protects us from harmful sunlight
What are the layers in the atmosphere? (cont…)
Mesosphere – coldest layer of atmosphere
Thermosphere – uppermost layer; temperatures also increases with altitude. This is where most small meteorites burn
up the location in the atmosphere that the
northern lights occur (aurora borealis)
Structure of the Atmosphere
Thermosphere
Mesosphere
Ozone MaximumStratosphere
Troposphere
Temperature
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Why is the atmosphere important?
80% of atmospheric gases are in the 15 km closest to Earth. This is a very thin layer compared to the Earth’s diameter, which is 12,756 kilometers.
The Earth is different than the other planets in our solar system because it has an atmosphere that can support life.
The atmosphere is an envelope of different gases (air) surrounding Earth.
mesosphere
thermosphere
© Boardworks Ltd 20097 of 6
What is the atmosphere made of?
The gases that make up the atmosphere are:
about 78% is nitrogen
about 21% is oxygen
the remaining 1% is mostly argon (0.93%)
with some carbon dioxide (0.035%), varying amounts of water vapor and
trace amounts of other gases
© Boardworks Ltd 20098 of 6
Does Earth’s atmosphere change?
About 3.5 billion years ago, the atmosphere on Earth would have been similar to the atmosphere on Mars today.
What theories are used to explain how the Earth’s atmosphere changed?
It would have contained large quantities of carbon dioxide, but not much oxygen or nitrogen.
The current composition of the air has been roughly the same for nearly 200 million years, but the amounts of different gases have changed over time.
© Boardworks Ltd 20099 of 6
The history of the atmosphere
© Boardworks Ltd 200910 of 6
Evolving atmosphere