2/25/10 Next homework due available in D2L! “The World We Create” NATS 101 Section 6.

2/25/10

Next homework due available in D2L!

““The World We Create”The World We Create”NATS 101NATS 101Section 6Section 6

Unit 2: Environmental Changes, Natural or Man-made?

Carbon dioxide (CO2) gas has some interesting properties and is easy to make at home. Let’s play with some CO2

gas. But first, I need to “make” some.

To make CO2 gas all you need is a container, some baking soda and some vinegar.

THE REACTION

Vinegar (Acetic acid) + baking soda (sodium bicarbonate) produces sodium acetate and carbonic acid…

The carbonic acid then breaks down into water and carbon dioxide gas. (For you chemistry buffs…)

HC2H3O2 + NaHCO3 NaC2H3O2 + H2CO3

Then H2CO3 H2O + CO2

1. Colorless

2. More dense than air

So what can we observe about CO2?

What about it’s thermal (heat related) properties?

Demonstration

Materials

• 2 glass jars, one with dry air, one with CO2 gas

• Light source• Digital recording

thermometers

• Illuminate each bottle equally• Monitor temperatures with the probes.• Formulate a hypothesis as to the

outcome …

Procedure

DemonstrationYour Part of the Experiment:

A Mini Debate!Each member of your group must choose a different hypothesis from the list below and explain why it must be true to the other group members. Try to be convincing!

1. The temperature within the bottle with CO2 gas in it will increase more than the bottle with dry air because …

2. The temperature within the bottle with the dry air will increase more that the bottle with CO2 gas because …

3. The temperatures within both bottles

will increase the same because …

Hypotheses

You have 3 minutes

The Butterfly Effect

The Bystander Effect

The Doppler Effect

The Greenhouse Effect

The Girl Effect


The Lucifer Effect

The Mozart Effect

The Nostradamus Effect

The Stroop Effect



The Doppler Effect


The Girl Effect


The Lucifer Effect

The Mozart Effect


The Stroop Effect

The Topic for Today?



The Doppler Effect


The Girl Effect


The Lucifer Effect

The Mozart Effect


The Stroop Effect



The Doppler Effect


The Girl Effect


The Lucifer Effect

The Mozart Effect


The Stroop Effect

The Topic for Today?

It’s hot in here!

What is a greenhouse for and how does it work?

What is a greenhouse for and how does it work?

• A greenhouse is a building constructed primarily of glass or plastics in which plants can be grown. The clear walls provides a contained, warm, humid environment that facilitates the growing of plants.

• These optimal growing conditions are caused by solar (light) energy passing through to the inside surfaces which are subsequently heated, which in turn heats the contained air.

• The closed environment of the greenhouse restricts the natural convection of air and consequently interior temperatures can be quite high.

• With the proper building materials the greenhouse can also store some of that interior heat allowing it to extend through the night to continue maintaining a suitable growing temperature.

Growing plants is possible in the Arctic

What do you already know?

• What ideas do you have about the “greenhouse effect”?

• Where have you experienced it in your everyday lives?

• Does the actual term “greenhouse effect” create a negative or positive image in your mind? Why?

I guess I really

overslept!

Objectives(You will be able to)

o Explain the natural process that moderates earth’s temperatures.

o Describe the atmospheric conditions that have been termed “The Greenhouse Effect”

o Identify the main gases in our atmosphere that participate in the Greenhouse Effect

o Explain how the concept of resonance can be used to explain the properties of such “greenhouse gases”;

o Apply the concept of “Greenhouse Effect” to analyze climatic conditions in other planets.

Our AtmosphereThrough the “greenhouse effect”, our planet’s atmosphere retains solar energy and keeps the global average temperature in a pleasant range.

Life would not exist without the greenhouse effect!

Without the greenhouse effect the earth would

have a temperature approximately 33 oF lower than what it is

currently.

Tucson

What do these charts tell us?

http://upload.wikimedia.org/wikipedia/commons/4/4c/Solar_Spectrum.png

So, how is our atmosphere heated?

Infrared light

How is our atmosphere kept warmer

than it would be otherwise?

Visible light

Infrared light

A small amount (~12%) of the incoming sun’s energy is absorbed directly by various “greenhouse gases” in the atmosphere. However, much of the sun’s energy (which is in the visible light spectrum) travels through the atmosphere and is absorbed by the earth.

Step 1

Visible light


Infrared light

Step 1

Visible light

A small amount (~12%) of the incoming sun’s energy is absorbed directly by various “greenhouse gases” in the atmosphere. However, much of the sun’s energy (which is in the visible light spectrum) travels through the atmosphere and is absorbed by the earth.


The earth absorbs the visible light energy, get’s hotter, and radiates thermal energy (as longer wave infrared radiation ) upwards into the atmosphere. This infrared radiation is absorbed by various “greenhouse” gases there.

Infrared light

Step 2

Visible light


Specific “greenhouse gases” in the atmosphere readily absorb infrared radiation. Those gases subsequently radiate energy in all directions including the ground which absorbs that radiation and subsequently gets warmer.

Infrared light

Visible light

Step 3


Earth’s Energy Sources

The surface of the Earth is warmer than it would be in the absence of an atmosphere because it receives energy from two sources: the Sun and the atmosphere.

Earth Heat Gains

1. Short-wave radiation from the sun..................… 34.7%

2. Long-wave radiation from the atmosphere......... 65.3%

Atmospheric Heat Gains

1. Short-wave radiation from the sun (incoming radiation) ............... 11.9%

2. Heat to atmosphere from condensation.(cloud formation) ........... 14.4%

3. Heat to atmosphere from convection/conduction ………………….. 4.4%

4. Long-wave radiation from earth (surface radiation)..............…… 69.4%

What do the following numbers tell us?

(State any Fact – No Numbers Please)

Citation: Pidwirny, M. (2006). "Atmospheric Composition". Fundamentals of Physical Geography, 2nd Edition.

Gases of Our Atmosphere

Helium0.00049%

Methane0.00017%

Carbon Dioxide 0.039%

Water1.96%

Hydrogen0.00005%

Nitrous Oxide0.00003%

Ozone0.00000%

Oxygen20.6%

Neon0.0018%

Argon0.91%

Nitrogen76.5%

0.000004%

Atmospheric Composition:The Non-Greenhouse Gases

• These gases are not sensitive to infrared wavelengths and as such do not absorb IR.

Nitrogen (N2) Oxygen (O2) Argon (Ar)

Natural • Water Vapor (H2O)

• Carbon Dioxide (CO2)

• Methane (CH4)

• Nitrous Oxide (N2O)

Synthetic

• Chlorofluorocarbons (CFCs)• Hydrofluorocarbons (HFCs)• Perfluorocarbons (PFCs)

• Sulfur hexafluoride (SF6)IR radiation is absorbed; IR is emitted.

Atmospheric Composition:The Greenhouse Gases

C:\Documents and Settings\vicente.ZIRCONIUM\My Documents\Stch420\NATS_S08\co2.mov

Greenhouse Gas Lifetimes

Greenhouse Gas Lifetime1 in AtmosphereWater vapor 10 days

Carbon dioxide 50 to 200 years

Methane 10 to 12 years

Nitrous Oxide 120 years

CFCs over 100 years

1DEFINITION:The atmospheric “lifetime” of a pollutant or reactant measures the time required for the restoration to approximately original concentration. .

Contribution to the Greenhouse Effect

http://www.geocraft.com/WVFossils/greenhouse_data.html

Water Vapor

• Water vapor comprises only 1% to 4% of Earth’s atmosphere but accounts for approximately 95% of Earth’s greenhouse effect.

Sources of Water Vapor

Oceans

Decomposition of plants

Volcanic Eruptions

Lifetime in atmosphere:10 days

Natural Sources of Carbon Dioxide(95% of CO2 production)

Lifetime in atmosphere:

50 – 200 years

Animal and plant respiration

Ocean – Atmosphere exchange

Volcanic eruptions

• CO2 comprises 0.04% of Earth’s atmosphere but accounts for approximately 18% of Earth’s greenhouse effect.

Man-made Sources of Carbon Dioxide(5% of CO2 production)

CH4 + 2 O2 CO2+ 2 H2O

Burning of Fossil fuels (methane combustion)

C + O2 CO2

Burning of Fossil fuels (coal combustion)

2C8H18 + 25O2 16CO2 + 18H2O

Burning of Fossil fuels (gasoline combustion)

CxHyOz + O2 CO2 + H20

Burning of wood

Methane It is formed when both bacteria that breakdown

organic matter in wetlands and bacteria that are found in cows, sheep, goats, buffalo, termites, and

camels produce methane naturally.

Lifetime in atmosphere:10 – 12 years

Nitrous Oxidepain killer, rocket propellant, engine fuel additive

Naturally produced by microbial processes in

water and soil.

Man-made sources include agricultural soil

management, waste management,

combustion processes, some acids production

Lifetime in atmosphere:

Approx. 120 years

How is Atmospheric Heat Retained?

We know that “greenhouse gases” in the atmosphere, such as CO2 and H2O, are

responsible for sustaining Earth’s temperature

What is it about certain molecules that causes heat to be retained? Why is CO2 a greenhouse gas but not, say O2?

Tacoma Narrows Bridge

http://video.google.com/videoplay?docid=4087615334344625698&ei=LoiAS8frEYqcqQPw8qS_Cg&q=tacoma+narrows+bridge+collapse&hl=en#docid=-3932185696812733207












Exploration of Ideas

• In your groups, take turns moving the base of the model back and forth, and observe its motion.

• What observations can you make about the three posts individually?

You have 1-2 minutes

Now on a larger scale…

Demonstration & Discussion

• Each individual post moves at its own natural rhythm

• How might we account for this occurrence?

Now to introduce some terms…

Amplitude

• Amplitude is the maximum distance an object moves from its natural position

• Can anyone provide a real world example of amplitude?

Amplitude (continued)

• In terms of the model, amplitude is the maximum distance the post moves from its natural, resting position

Frequency• Frequency is the number of times something is

accomplished in a certain time span (usually measured in Hertz = cycles per second)

• Can anyone provide a real world example of frequency?

Frequency (continued)

• In terms of the model, frequency is the number of times you move the model back and forth in one second, also known as the driving frequency

• The number of times the post moves back and forth in one second is known as the natural frequency

In your groups, use your model to complete the

worksheet

You have 5-10 minutes

Let’s tie these concepts together…

Resonance• Resonance is the term for what happens

to a system when we apply a driving frequency that matches the natural frequency, creating an increase in the amplitude

• CO2 and resonance are intrinsically intertwined to explain the greenhouse effect on the microscopic level

• http://www.kcvs.ca/site/projects/chemistry.html

CO2 and Resonance

Resonance of CO2

Resonance

Resonance is the tendency of a system to oscillate at maximum amplitude when forced

at its natural frequencies.

http://www.youtube.com/watch?v=PlpXrB4NP3w

Back to the Demonstration

Your Part of the Experiment:

So, who was right?

1. The temperature within the bottle with CO2 gas in it will increase more than the bottle with dry air because …

2. The temperature within the bottle with the dry air will increase more that the bottle with CO2 gas because …

3. The temperatures within both bottles

will increase the same because …

Hypotheses

Switch to Laptop

Experiment Results Trial 1

Experiment Results Trial 2

Application

Now we have seen the greenhouse effect in action and we know how it

affects Earth.

How does the greenhouse effect work on other planets?

Let’s analyze some data and see.

Other Planets

PlanetSurface

Temperatures

Composition of Atmosphere

Atmosphere

Density (Earth = 1)

Venus 850-890 °F 96% CO2

4% N2100

Earth40-90 °F

(Daytime)

80% N2, 20% O2

CO2 <<0.01%1

Mars80 to -210 °F

(-70°F avg)

95% CO2

3% N2

0.01

Greenhouse Gases

– What would happen if all the greenhouse gases were removed from the atmosphere?

– Use the data provided on the previous slide to explain why the surface temperatures differ so much between the 3 planets: Venus, Earth, and Mars.

You have 3 minutes.

Other Planets

PlanetSurface

Temperatures

Composition of Atmosphere

Atmosphere

Density (Earth = 1)

Venus 850-890 °F 96% CO2

4% N2100

Earth40-90 °F

(Daytime)

80% N2, 20% O2

CO2 <<0.01%1

Mars80 to -210 °F

(-70°F avg)

95% CO2

3% N2

0.01– What would happen if all the greenhouse gases were removed from the atmosphere?

– Use the data provided above to explain why the surface temperatures differ so much between the 3 planets: Venus, Earth,

and Mars.

Last Minute ClarificationThe “Greenhouse Effect” and Global Warming are not

the same thing.

The Greenhouse Effect (the process) is a natural process which causes the surface of the Earth to be warmer than it would be in the absence of an atmosphere.

Global Warming (the effect) is the name given to an unexpected increase in the lower atmospheric temperatures. This has been blamed on the “Enhanced Greenhouse Effect”.

So, what do you know? Or So what, do you know?

True or False

1. The greenhouse effect is a man made phenomenon.2. The atmosphere consists mostly of greenhouse gases and that’s

why we stay as warm as we do.3. The most common greenhouse gas is CO2 and that is why its

emissions has been such a hot topic for global discussion.4. The earth receives nearly twice as much energy from the

atmosphere than what it does directly from the sun.5. The earth’s surface is kept warmer in a process that is similar to

what takes place in an actual greenhouse. That is why they call it the Greenhouse Effect.

6. All types of gas molecules can resonate, but only some do so in the presence of IR radiation wavelengths.

7. Venus is inhospitable due to its extensive atmospheric greenhouse effect.


True or False

1. The greenhouse effect is a man made phenomenon. False2. The atmosphere consists mostly of greenhouse gases and that’s

why we stay as warm as we do.3. The most common greenhouse gas is CO2 and that is why its

emissions has been such a hot topic for global discussion.4. The earth receives nearly twice as much energy from the






True or False


why we stay as warm as we do. False3. The most common greenhouse gas is CO2 and that is why its

emissions has been such a hot topic for global discussion. 4. The earth receives nearly twice as much energy from the

atmosphere than what it does directly from the sun. 5. The earth’s surface is kept warmer in a process that is similar to





True or False



emissions has been such a hot topic for global discussion. False4. The earth receives nearly twice as much energy from the






True or False




atmosphere than what it does directly from the sun. True5. The earth’s surface is kept warmer in a process that is similar to





True or False





what takes place in an actual greenhouse. That is why they call it the Greenhouse Effect. False




True or False






6. All types of gas molecules can resonate, but only some do so in the presence of IR radiation wavelengths. True



True or False







7. Venus is inhospitable due to its extensive atmospheric greenhouse effect. True


True or False







7. Venus is inhospitable due to its extensive atmospheric greenhouse effect. True

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