Transcript L2 - Introduction to Atmosphere PPT

THE ATMOSPHERE
Objective for the day

By the end of the day…

SWBAT
 Describe
the composition of the Earth’s atmosphere.
Definitions
What do you think of when you hear the word atmosphere?


Atmosphere: The layer of gases that surrounds the
planet
Temperature: NOT heat. The measurement of how
quickly or slowly molecules move around.
Where did the gases in the atmosphere
come from?

Let’s take some guesses!
Volcanic Eruptions!
What kind of gases?
Such as Argon
and Carbon
dioxide
Most of Earth’s
atmosphere is not made
up of oxygen. It’s
mostly made of nitrogen.
This is good because
actually, with too much
oxygen we would all die.
Our insides would start
to “rust!”
DRAW THIS
Layers of the Atmosphere
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The four main layers of
the atmosphere are
classified according to
changes in temperature.
These layers are the
troposphere, the
stratosphere, the
mesosphere, and the
thermosphere.
Troposphere



We live in here!
The inner, or lowest, layer of
the atmosphere.
This is where Earth’s weather
occurs (rain, clouds, etc.)
Stratosphere


Above the troposphere.
Contains a layer of ozone (a special form of oxygen)
 The
ozone layer absorbs harmful energy from the sun and
keeps us from overheating.
Mesosphere

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
Above the stratosphere, a
drop in temperature marks
the beginning of the
mesosphere.
The outer mesosphere is the
coldest part of the
atmosphere: around -90°C
(-134°F)
*How do shooting stars form?
Thermosphere



The air is very thin (the air
molecules expanded apart from
each other)
This layer blends gradually with
outer space
The air is very HOT (up to
1,800°C)
 This

is hotter than a steel furnace
Why is it hot?
 The
sun hits this layer first
Getting thinner
A Question to rattle your brains…



Even though there is a high temperature in
the thermosphere, you would NOT feel hot.
An ordinary thermometer would show
around 0°C. Why is this???
Temperature: NOT heat. The measurement of how quickly
or slowly molecules move around.
The gas molecules in this layer are moving very
fast (high temperature), but the molecules are
spaced far apart in the thin air. And there aren’t
enough of them to collide with a thermometer
and warm it very much.
A thermometer
would not
detect the
molecules’
energy.
Questions for us…let’s DO it!

How does altitude affect density of the air? (Think of a
convection current)
 As

altitude increases, density decreases.
Alexis is running to the top of Mt. Everest. Why is it
harder for her to breathe once she reaches the top?
 The
air is less dense (thinner) and there are fewer oxygen
molecules to take in with each breath.
Questions for us…let’s DO it!


Molecules in the air can create resistance that can
slow objects orbiting Earth.
Why do you think satellites orbit Earth at such high
altitudes?
 Because
the air is less dense, the air molecules create less
resistance to slow down orbiting satellites.

Which layer are satellites mostly found?
 The
thermosphere because the air is very thin.
It’s Game Time.
Directions:

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

Sit with a partner or in a team of three.
Clear your desks COMPLETELY except for a pen or
pencil!
Work as a team to answer your game sheet
(handout)
When finished, notify the teacher!
Exit Ticket (3 questions)
1) What are the two main gases that make up the atmosphere?
2) Can you name another gas in the atmosphere?
3) List two layers of the atmosphere and a specific characteristic
about each layer.
Example: (do not use this one) “The troposphere is the layer we
live in.”