Transcript Electromagnetic Radiation and Global Climate change

Electromagnetic Radiation
and Global Climate change
Chapter 9
Trapped in a Newtonian
Universe
• Though Newton’s Apple and Calculus
are helpful, his theories are only as good
as the next round of evidence.
• Now we have electromagnetic fields and
energy without tiny solid particles.
• The Newtonian Universe is most popular
and helpful for the everyday
understanding of how the world works,
but our popular view is a few centuries
behind the science at work.
What is Light?
• James Clerk Maxwell theorized that
electromagnetic waves were disturbances in
electromagnetic fields.
• A magnetic field can be created by a change
in the electric field.
• The disturbance in the electromagnetic field
is called an electromagnetic wave that does
not need a physical medium to propagate
through and, as Maxwell’s math predicted,
has a speed of about 300,000 km/s, which is
the known speed of light.
An electromagnetic wave
A disturbance in an electro magnetic field where a change in a
magnetic field creates a change in an electric field that carries
energy.
Electromagnetic Spectrum
The smaller the wavelength, the higher the frequency ,because all
electromagnetic waves travel at speed C (Speed of light) and will therefore
have more energy associated with them. For example, you can feel light
energy in the form of thermal radiant energy.
Solar radiation
This is a graph depicting what our eyes are sensitive enough to notice; the
small part of the electromagnetic spectrum we call light. We experience this
all the time. It is the visible, infrared, and ultraviolet parts of the
electromagnetic spectrum
Where for Art Thou?
• In 1928, Chlorofluorocarbons were not
just a difficult and arduously long word,
they were a wonderful find for
refrigeration, where chemically inert,
non-flamable, and nontoxic to humans.
• But in1974, scientists began to ask where
these chemicals were going.
?????
CFC and O3
• CFC is broken down in the stratosphere
by a large amount of radiation and
releases Cl in the atmosphere.
• O3 (ozone) reacts with Cl (chlorine) in
this manner: Cl + O3 -> ClO + O2 Which
destroys the Ozone that protects the
planet from UV rays.
• ClO + ClO + sunlight -> Cl + Cl+ O2
Which releases more Cl to react with
Ozone.
Holes In Our defenses:
The Ozone is leaving us
• 1977 Antarctica, team observed ozone
concentrations dropping and plummeted 40% in
1984 covering an area larger than the USA. An
Ozone Hole.
• 1978 first regulation for CFCs: USA initiated a
ban on spray propellants.
• 1987 Ozone Treaty 47 nations agreed to phase out
ozone-destroying chemicals by the year 2000.
• Cancer is the main concern as more and more UV
radiation gets through our weakened defense;
the ozone layer.
Global Warming
• Green house gases, such as water vapor and carbon
dioxide, absorb infrared radiation to keep the
surface warm enough for life. It’s sort of like a
blanket to snuggle up in. 
• Since Industrialization, carbon dioxide
concentrations have risen 34%
• Such a rise in concentrations of greenhouse gases
has warmed the planet, the oceans, and melted
glaciers.
• Global warming can cause wacky weather patterns
and upset the balance of sensitive ecosystems such
as coral reefs that can only survive in waters that stay
a certain temperature all year round.
Carbon dioxide concentrations on the right,
Global Temperature anomaly on the left.
As CO2 concentrations have increased, so has the average
temperature.
Quiz
1. If you Electrically charge a comb by
brushing your hair, and then shake
it, at a frequency of 1 Hz, what will
this produce?
A)A sound wave
B) An electromagnetic field vibrating
but no electromagnetic wave
C)An electromagnetic wave
2. When energy from the sun is
absorbed by your skin it
A)Remains there as electromagnetic
energy
B) Remains there as radiant energy
C)Transforms into nuclear energy
D)Transforms in to thermal energy
3. Refrigerators cool the objects
inside. How do they affect your
kitchen?
A)They cool it
B) They warm it
C)They don’t affect the temperature
4. A key step in ozone destruction by
CFCs is
A)CFCs break down in the
stratosphere to release chlorine
B) CFCs break down in the
stratosphere to release carbon
C)Solar radiation breaks down O3
D)CFCs directly combine with Ozone
5. A climate model that has been
tested many times and found to be
accurate is an example of
A)A scientific theory
B) A scientific hypothesis
C)A scientific fact
Answers
1.
2.
3.
4.
5.
C
D
B
A
A
Try some of the Review Questions
at the end of the chapter for extra
study.