Transcript I. Atmosphere - Bethpage Union Free School District

Atmosphere
Aim: What is the composition of
Earth’s atmosphere?
Do Now:
• Which material do you think
best represents the
thickness of the atmosphere
around the Earth?
– The thickness of a sponge?
– The thickness of a stack of
paper plates?
– The thickness of a plastic
bag?
1. What is atmosphere?
• The very thin layer of gases that surrounds the
Earth.
• The atmosphere is about 60 miles thick
• Most of the gases are found within 7 miles of
Earth’s surface.
The atmosphere thins out: as you get farther from
the Earth, there are fewer molecules of gas .
2. How does the atmosphere
stay in place?
• Earth’s gravity keeps the atmosphere from floating
away.
3. What does the atmosphere do?
•
•
•
•
Traps energy from sun to keep Earth warm
Provides temperatures suitable for life
Provides gases for organism respiration
Protects Earth from ultra violet (UV)
radiation from the sun
• Protects meteoroids from hitting Earth
4. What is the atmosphere
made of?
• 78% Nitrogen
• 21% Oxygen
• 1% all others
–
–
–
–
Argon (.9%)
Carbon dioxide (.04%)
Water vapor
Aerosols (dust, soot,
ash, smoke, sea salt)
Nitrogen (N2) – 78%
N2 – bacteria –
(muscle)
plants – animals – proteins
N2 can’t be used directly
by humans.
Bacteria “fix it” so it can
be used by plants and
animals in the nitrogen
cycle.
Oxygen (O2) – 21%
• Oxygen (O2)
– Used by animals for respiration
– Released by plants as waste from cells
– Reacts with UV radiation to become ozone (O3)
Carbon Dioxide (CO2)
– Released by animals as waste from cells,
used by plants for photosynthesis
– Major greenhouse gas* = traps heat to
warm the Earth
- Also a pollutant from the burning of fossil
fuels that causes excess global warming
Carbon/Oxygen Cycle
Water Vapor (H2O)
– Gas form of water affects condensation of
clouds and weather events (rain, snow)
– Part of the water cycle
Water Cycle
Aerosols
– Particles of dust, smoke,
soot, sea salt
– Blocks some incoming
radiation from the sun,
decreasing the
temperature of Earth
– Needed for condensation
of water into rain or snow
(vapor must condense into
a liquid onto a solid
particle like dust)
Brainstorm: Think, pair, share
• Where do aerosols come from?
Summary
• Which gases are consumed by
organisms?
• Which gases affect climate and weather?
• Which gases are easily changed by
human activities?
HW: Where did the atmosphere
come from?
• Submit a short, typed summary paragraph
or 2 that describes how the original
atmosphere formed, where oxygen
originated from, and according to the
ESRT, when did the oceanic oxygen start
entering the atmosphere?