The Atmosphere Chapter 17

#1 The Earth’s lower atmosphere is composed of a mixture of gases we call air. The Earth’s lower atmosphere is composed of a mixture of gases we call air. The main gases in air are nitrogen (78%), oxygen (21%), argon, and carbon dioxide. The main gases in air are nitrogen (78%), oxygen (21%), argon, and carbon dioxide. There also is a large amount of water vapor in air. There also is a large amount of water vapor in air. This varies widely with the season and location. This varies widely with the season and location.

#2 Heat is not a thing, but is form of energy. Heat is not a thing, but is form of energy. That is to say, heat can be stored in substances, such as water and solids substances. That is to say, heat can be stored in substances, such as water and solids substances.

#2 Continued Heat energy moves in 3 different ways. Heat energy moves in 3 different ways. First, radiation is the transfer of heat energy through empty space, such as how heat gets to the Earth from the Sun. First, radiation is the transfer of heat energy through empty space, such as how heat gets to the Earth from the Sun.

#2 Continued again Second, heat that moves through substances that are in direct contact with one another is called conduction. Second, heat that moves through substances that are in direct contact with one another is called conduction. Walking barefoot on hot pavement would be an example of heat transfer by conduction. Walking barefoot on hot pavement would be an example of heat transfer by conduction.

#2 One more time Third, convection is the transfer of heat energy by changes in density of heated materials. Third, convection is the transfer of heat energy by changes in density of heated materials. Example of this would be warm air rising and cooler air sinking. Example of this would be warm air rising and cooler air sinking.

#3 Heat and temperature are not the same thing. Heat and temperature are not the same thing. Temperature is the measurement of the average kinetic energy of the molecules of a substance. Temperature is the measurement of the average kinetic energy of the molecules of a substance. Huh???? Huh????

#3 Continued OK, that sounds complicated, lets just say that the temperature is really a measurement of how fast the molecules of a substance are moving. OK, that sounds complicated, lets just say that the temperature is really a measurement of how fast the molecules of a substance are moving. High temperature means the molecules are moving fast, low temp. the molecules are moving slower. High temperature means the molecules are moving fast, low temp. the molecules are moving slower.

#4 Heat is the total amount of kinetic energy in a substance. Heat is the total amount of kinetic energy in a substance. For example, there is more heat in a bathtub full of cold water than in a boiling cup of tea, even though the tea has a higher temperature. For example, there is more heat in a bathtub full of cold water than in a boiling cup of tea, even though the tea has a higher temperature. A thermometer measures temperature, not heat. A thermometer measures temperature, not heat.

#5Temperature scales are completely arbitrary. Here is how they compare. FahrenheitCelsiusKelvin Absolute zero Freezing Pt. of Water Normal Room Temp. Approx 72 Approx 23 Approx 296 Human Body Temp Boiling Pt. of Water

#6 The lowest area of the atmosphere is called the troposphere. The lowest area of the atmosphere is called the troposphere. In the troposphere the temp. decreases as you go up in altitude. In the troposphere the temp. decreases as you go up in altitude. It is generally warmer near the surface because the ground absorbs heat energy then radiates the heat energy back to the air directly above it. It is generally warmer near the surface because the ground absorbs heat energy then radiates the heat energy back to the air directly above it.

#6 Continued When the temp. stops decreasing that is called the tropopause. When the temp. stops decreasing that is called the tropopause. The density of the atmosphere also decreases as you go up in altitude. The density of the atmosphere also decreases as you go up in altitude. The troposphere contains about 80% of the total mass of the atmosphere. The troposphere contains about 80% of the total mass of the atmosphere.

#7 The next layer of the atmosphere is the stratosphere. The next layer of the atmosphere is the stratosphere. The temperature actually increases in the stratosphere. The temperature actually increases in the stratosphere. This rise in temperature is caused by the presence of ozone, which is a form of oxygen that consists of 3 atoms of oxygen. This rise in temperature is caused by the presence of ozone, which is a form of oxygen that consists of 3 atoms of oxygen. Ozone protects us from ultraviolet radiation.(UV) Ozone protects us from ultraviolet radiation.(UV)

#7 Continued The stratosphere is followed by the mesosphere, which is about km above the Earth. The stratosphere is followed by the mesosphere, which is about km above the Earth. Again, temp. decreases in the mesosphere. Again, temp. decreases in the mesosphere. The uppermost layer of the atmosphere is the thermosphere, which has very little air in it, but the temp. can actually be very high. The uppermost layer of the atmosphere is the thermosphere, which has very little air in it, but the temp. can actually be very high.

#8 There are many factors that cause temperatures to vary so widely around the Earth. There are many factors that cause temperatures to vary so widely around the Earth. Probably the main factor is the angle and duration of the Sun’s radiation. Probably the main factor is the angle and duration of the Sun’s radiation. This variation is due to the tilt of the Earth’s axis with respect to it’s orbit around the Sun. This variation is due to the tilt of the Earth’s axis with respect to it’s orbit around the Sun.

#8 Continued The Earth is actually closer to the Sun in the winter than it is in the summer, but the Sun’s rays are much more direct ( in the northern hemisphere) in summer than winter. The Earth is actually closer to the Sun in the winter than it is in the summer, but the Sun’s rays are much more direct ( in the northern hemisphere) in summer than winter. Also, the Sun shines longer per day in the summer than in the winter. Also, the Sun shines longer per day in the summer than in the winter.

#9 The further north you are located on the globe makes a huge difference in the angle (intensity) of the Sun’s radiation. The further north you are located on the globe makes a huge difference in the angle (intensity) of the Sun’s radiation. If you are located on the Tropic of Cancer and the Tropic of Capricorn, the Sun’s angle never changes much, but the more north or south you go, the changes are major. If you are located on the Tropic of Cancer and the Tropic of Capricorn, the Sun’s angle never changes much, but the more north or south you go, the changes are major.

#10 Another factor that causes temperature variations on the Earth is the amount of cloud cover. Another factor that causes temperature variations on the Earth is the amount of cloud cover. If a place is cloudy most of the time, it probably doesn’t get very hot. If a place is cloudy most of the time, it probably doesn’t get very hot.

#11 The temperature of land varies much more than the temperature of water. The temperature of land varies much more than the temperature of water. Places located near large bodies of water, such as near the ocean have much more stable temperatures than places far from water. Places located near large bodies of water, such as near the ocean have much more stable temperatures than places far from water. This is because water is much more difficult to heat up and cool down than land is. This is because water is much more difficult to heat up and cool down than land is.

#12 Air pollution is any airborne gas or particle that occurs at a concentration capable of doing harm to humans or the environment. Air pollution is any airborne gas or particle that occurs at a concentration capable of doing harm to humans or the environment. Some air pollution is natural, such as volcanoes and some forest fires. Some air pollution is natural, such as volcanoes and some forest fires. But human activity produces significant amounts of air pollution. But human activity produces significant amounts of air pollution.

#13 Here are some of the nasty things that the EPA has identified that we should keep our eye on. AIR POLLUTANT MAJOR SOURCES EFFECTS Carbon Monoxide (CO) Engine exhaust Impairs oxygen intake, can be deadly Nitrogen dioxide (NO 2 ) Engine exhaust, coal, fossil fuels Lung irritation, acid rain, smog Sulfur dioxide (SO 2 ) Fossil fuels, factories, volcanoes Lung irritation, acid rain Particulate matter Factories, fossil fuels, power plants, volcanoes Respiratory problems, cancer Lead (Pb) Factories Nerve damage Ozone (O 3 ) Reaction of nitrogen oxides and hydrocarbons with sunlight Respiratory problems

#14 Acid precipitation (rain and snow) form when sulfur dioxides and nitrogen dioxides react with water in the atmosphere. Acid precipitation (rain and snow) form when sulfur dioxides and nitrogen dioxides react with water in the atmosphere. Acidity is measured by the pH scale. Acidity is measured by the pH scale. The pH scale runs from 0 to 14. The pH scale runs from 0 to is right in the middle of the scale and would be neutral (distilled water) 7 is right in the middle of the scale and would be neutral (distilled water)

#14 Continued Acid precipitation is anything below 5.6 on the pH scale. Acid precipitation is anything below 5.6 on the pH scale. The difference between acid levels from one number to the next, say from 6 to 7, is a factor of 10. The difference between acid levels from one number to the next, say from 6 to 7, is a factor of 10. That means that a 4 is 100 times more acidic than a 6. That means that a 4 is 100 times more acidic than a 6. Increased acid levels in the environment (low pH) can be harmful to wildlife as well as building and natural rock features (limestone especially) Increased acid levels in the environment (low pH) can be harmful to wildlife as well as building and natural rock features (limestone especially)

#15 Smog is the term for smoky fog. Smog is the term for smoky fog. Smog often results from the burning of fossil fuels, such as in automobiles, power plants, and factories. Smog often results from the burning of fossil fuels, such as in automobiles, power plants, and factories. One situation that can make smog linger is when a temperature inversion occurs. One situation that can make smog linger is when a temperature inversion occurs. When a temperature inversion occurs, cold air is trapped below a layer of warmer air. When a temperature inversion occurs, cold air is trapped below a layer of warmer air. When this occurs, the air doesn’t move much and stays in place. When this occurs, the air doesn’t move much and stays in place. If there is smog in the atmosphere, it stays in place and doesn’t get moved out. If there is smog in the atmosphere, it stays in place and doesn’t get moved out.

#16 Another atmospheric issue is ozone depletion. Another atmospheric issue is ozone depletion. Ozone protects us from UV rays, and the use of some chemicals (chlorofluorocarbons) CFCs, causes deterioration of ozone. Ozone protects us from UV rays, and the use of some chemicals (chlorofluorocarbons) CFCs, causes deterioration of ozone. CFCs were used as the coolant in air conditioners and refrigerators, but have been replaced by more environmentally friendly compounds. CFCs were used as the coolant in air conditioners and refrigerators, but have been replaced by more environmentally friendly compounds.

#17 Another issue is global warming. Another issue is global warming. There is much debate as to whether the Earth’s average temperature is rising, and if it is increasing, what is causing the warm up. There is much debate as to whether the Earth’s average temperature is rising, and if it is increasing, what is causing the warm up. There is no doubt that the carbon dioxide level of the atmosphere has increased in the past 100 years due to the burning of fossil fuels, but there is great debate as to whether this is a natural phenomenon, or actually caused by human activity. There is no doubt that the carbon dioxide level of the atmosphere has increased in the past 100 years due to the burning of fossil fuels, but there is great debate as to whether this is a natural phenomenon, or actually caused by human activity.

The End!!!!