Presentation on theme: "Question: Describe a greenhouse. What is it? What is it like inside and why? Answer: ……… Question of the Day Turn In: -Air Pressure Lab -p. 605 CYU 2."— Presentation transcript:
Approximately half the light that comes from the sun doesnt make it to the surface of the earth.
X-rays, a lot of incoming IR and UV are absorbed before they reach the surface.
Some of the light that reaches the earths surface is changed to heat (IR) and is trapped by Greenhouse Gases in the atmosphere.
How does a Greenhouse work? Whats different about the two waves shown in the picture? –Different wavelengths Visible light (from the sun) –Has shorter wavelengths –Can pass through glass/ greenhouse gases. Infrared light (heat) –Has longer wavelengths. –Cannot pass through glass/ greenhouse gases and is reflected back. Draw this picture noting the difference in wavelength
The Greenhouse Effect on Earth The greenhouse gases act just like the glass in a greenhouse.
The Greenhouse Effect is Good for Life on Earth Without the Greenhouse Effect –Reflected IR radiation (heat) would be lost to space –Earths temperature could vary from about -380 to 250 o F during a day (like on the moon)
Greenhouse Gases –Dont make up a very large percentage of the atmosphere, but have a significant warming effect.
Greenhouse Gases CO 2 (carbon dioxide) CH 4 (methane) NO x (Nitrous oxides) CFCs (Chloroflourocarbons) H 2 O (Water Vapor)
So Whats The Big Deal?? The human-caused enhancement of the greenhouse effect is called global warming and its bad because its associated with climate destabilization
Runaway Greenhouse Effect Atmosphere of Venus is mostly CO 2 Temperatures can reach A. 300 o F B. 1000 o F C. 500 o F D. 860 o F Artists idea of what Venus surface might look like
CO 2 Concentration on Earth What is the trend of CO 2 Concentration in earths atmosphere?
Global Warming/Climate Change Even small increases in the amounts of CO 2 in the atmosphere can increase our temperature AND change the climate!
Where Does CO 2 Come From? Combustion of Fossil Fuels in –Power Plants –Cars –Factories
Where Does CH 4 (methane) Come From? –Naturally occurring in swamps –Released as by-product of rice and cattle farming.
Where Does NO x Come From? Burning of fossil fuels like gasoline, coal, and natural gas breakdown of fertilizers in soil
CFCs (Chlorofluorocarbons) Also degrade ozone layer in addition to being a greenhouse gas Come from –Spray cans (banned from USA spray cans in 1995) –Coolants in refrigeration systems and air conditioners –Solvents to clean electronic components –Blowing agents in the production of plastic foams like styrofoam
Where Does H 2 O (Water Vapor) Come From? Its all around us most abundant greenhouse gas not directly influenced by human activity (So we dont worry too much about it!)
Which greenhouse gas is most responsible for global warming? A.Methane B.Water Vapor C.CFCs D.Carbon Dioxide
Effects of Global Warming Which of the following are probable results of global warming due to excessive greenhouse gases? A.thinning of polar ice caps B.floods C.Droughts/ water shortages D.All of the above In addition to: rising sea levels (threatening millions of people) changing precipitation patterns heat waves disruptions of forests and agriculture Yet we continue this uncontrolled, global experiment!
What Can We Do About It? Reduce Greenhouse Gases by: Use alternative energy that doesnt emit CO 2 Conserve energy by turning off lights, riding bicycles, etc. Reduce, Reuse & Recycle And the list goes on!
2.Identify which of the following gases is most abundant in Earths atmosphere today. a. argonc. oxygen b. nitrogend. carbon dioxide 2. Nitrogen is most abundant in Earths atmosphere today. p. 605 CYU 2-7 3. Compare Earths early atmosphere with its present atmosphere. 3. Earths early atmosphere was composed of many gases that would be poisonous to us today. As life forms evolved and began to photosynthesize, oxygen was produced. Once animals adapted to breathing oxygen, they began to give off carbon dioxide, balancing the production of oxygen.
4.Arrange the steps of the oxygen-carbon dioxide cycle in the correct order: a.Animals breathe oxygen b.Plants produce oxygen c.Plants use carbon dioxide d.Animals exhale carbon dioxide 4. The correct order is b, a, d, c. b. Plants produce oxygen a. Animals breathe oxygen d. Animals exhale carbon dioxide c. Plants use carbon dioxide p. 605 CYU 2-7
5. Explain why the following statement is incorrect: global warming could cause oceans to rise, so the greenhouse effect must be eliminated completely. 5. If we were to eliminate the greenhouse effect completely, the worlds climate would become too cold for humans to survive. p. 605 CYU 2-7
6. Predict how much colder it is at the top of Mount Everest, which is almost 9km above sea level, than it is at the Indian coastline. Consider only the difference in altitude. (Hint: the temperature in the troposphere decreases by 6°C/km) 6. The temperature at the top of Mount Everest is about 54°C colder. 9km x 6°C/km = 54°C
7. In 1982, Larry Walters rose to an altitude of approximately 4900m (just over 3 miles) on a lawn chair attached to 45 helium-filled weather balloons. Give two reasons why Walterss efforts were dangerous. 7. Walterss efforts were dangerous because the oxygen content of the air is considerably lower at that altitude and the temperature is extremely cold. p. 605 CYU 2-7