This Document Contains Chapters 17 to 20 Chapter 17 Earth’s Weather Contents The Atmosphere Composition of the Atmosphere Atmospheric Pressure Warming the Atmosphere Structure of the Atmosphere A Closer Look: A Hole in the Ozone Layer? The Winds A Closer Look: The Windchill Factor Local Wind Patterns Global Wind Patterns Water and the Atmosphere Evaporation and Condensation Humidity The Condensation Process Fog and Clouds Precipitation Weather Producers Air Masses Weather Fronts Waves and Cyclones Major Storms Weather Forecasting Climate Major Climate Groups Regional Climatic Influence Climate Change Causes of Climate Change Global Warming A Closer Look: El Niño and La Niña Overview Even if we do not consider the multitude of different chemicals present as the result of pollution, the atmosphere of our planet contains a considerable variety of elements and compounds. The atmosphere is a remarkably pure gaseous solution of nitrogen, oxygen, carbon dioxide, and argon with traces of neon, helium, methane, krypton, hydrogen, xenon, ozone, radon, and so forth. Only two of these gases (nitrogen and oxygen) make up about 99 percent of the total composition. The composition of gases in the atmosphere is the same percent everywhere around Earth up to an altitude of 25 km (about 15 mi), except for small variations of carbon dioxide. About half of the radiation from the Sun makes it through the atmosphere. Most of the wavelengths shorter than those of visible light are absorbed by ozone in the upper atmosphere. About 30 percent of the radiation is reflected back into space. The radiation that reaches the surface is mainly in the form of visible light and longer wavelengths. The radiation that does reach Earth's surface is absorbed, increasing the temperature of materials on the surface. These materials re-radiate the absorbed energy with longer wavelengths of infrared radiation. The longer wavelengths are absorbed in the atmosphere by molecules of water vapor and carbon dioxide, increasing the temperature. The lower atmosphere is heated from the bottom up and the process is called the greenhouse effect. If a mass of air is over a particular location for a sufficient amount of time, from several days to a week or so, it begins to acquire nearly homogeneous temperature and moisture conditions from the surface it is over. These horizontally uniform temperature and moisture conditions identify the physical properties of different air masses, which are named from these properties. Thus, tropical air masses are hot, and polar air masses are cold; maritime air masses are moist, and continental air masses are dry. Pressure differences and prevailing wind belts cause massive air masses to break loose from their source regions. This sends a huge mass of polar air southward or a huge mass of tropical air northward. These masses are shifted eastward by the prevailing westerlies. Thus most of the United States can have weather influenced by continental polar air for a few days. Then weather can be influenced by a mass of maritime tropical air, and an occasional weather pattern produced by a mass of maritime polar air. In general, continental polar air drifts farther south in the winter and maritime tropical air moves farther north in the summer. Moving air masses bring rapid weather changes along the leading edge of the mass (frontal weather), and slow changes occur after the air mass arrives (air mass weather). Cold air is denser than warm air and wedges under the warm air. A front is usually convex in the direction of movement, acting much as the surface of a huge bubble of air moving across the land. Since warm air is less dense than cold air, a moving warm air mass overrides as it pushes a colder air mass. The overriding air mass produces a series of cloud changes that foretell the coming of a warm air mass. Cirrus clouds and then cirrostratus clouds, which can produce a halo around the Sun or Moon, may appear some 12 hours before a warm front arrives. Weather forecasting is based on information about air masses, high- and low-pressure systems, and the movement of fronts. Information is gathered from satellite photographs, radar, and other sources of observations and used to construct a weather map, which is analyzed and interpreted for coming changes in different locations. Climate is the average weather that occurs over a period of years at a given location. There are a number of different climatic factors that can be used to distinguish one climate from another, but any scheme used is going to be artificial. Boundaries between general climatic patterns are not sharp but are wide zones of transition. Climate regions actually blend into one another gradually. Suggestions 1. Students will be interested in various phenomena of the atmosphere such as why the sky appears blue, northern lights, why sunsets are red, and why airplanes fly in the stratosphere. 2. If possible, borrow an instrument package used with weather balloons and explain how the instruments provide information about the atmosphere. 3. On a calm, sunlit day, have students measure air temperatures just above the grass in a field and just above the asphalt or concrete of an adjacent parking lot. Use this information as the basis for a prediction about which way the air is moving near the surface between the grass and parking lot. Use soap bubbles to indicate the direction of air movement and test the prediction. 4. Watch for newspaper reports of Santa Ana and Chinook winds (compressional winds). Sometimes the results of these warm winds can be very dramatic, melting as much as ten inches of snow or more in a single day. 5. Have students do a literature search to determine how the doldrums, trade winds, and horse latitudes got their names. They could also find how the global wind belts have affected history, for example, what discoveries were a result of the wind belts and how the wind belts affected trade. 6. The requirements for the condensation process can be demonstrated with a large, small- mouth jug. Add a small amount of water to the jug and shake it thoroughly to saturate the air. Place your mouth against the clean opening, then blow into the jug to increase the air pressure inside. Quickly release the pressure, explaining that the expansion will cool the air and result in condensation. Nothing happens when this is done. Now add a smoking match to the jug. When the process is repeated, a fog forms in the jug. Explain the necessary conditions of saturated air, cooling, and the presence of condensation nuclei (provided by the match) in order for condensation to form. 7. Have students record daily temperature, barometric pressure, wind direction, and wind velocity in the morning, at noon, and in the evening. Also have them note cloud cover and amount of precipitation every day. At the end of a week, have a class discussion of correlation between the various factors measured and the type of weather that prevailed during the week of study. 8. Use a series of daily weather maps to identify kinds of air masses and track their movement over time. Look for correlation between the different kinds of air masses and the weather that each brings to your location. Have someone obtain hourly temperature readings for the day before an air mass arrives and for a day after it arrives. Graph the temperature readings and determine when the air mass arrived. 9. Elementary school teachers sometimes claim they can predict a coming storm (low- pressure area) from the noise and activity level of their classes. Some students might be interested in investigating if there is any basis for such claims of changes in the social behavior related to atmospheric pressure changes. 10. The effect of sunlight at different latitudes can be demonstrated with a strip of paper with equally spaced drops of wax from a candle. The paper strip is taped to a globe, running from pole to pole, with the wax drops on the outside surface. A strong spotlight directed toward the equator will melt the wax drops on the equator first, then poleward. 11. Many new buildings are now constructed with a window overhang or awning so that sunlight shines in a south-facing window in the winter but not during the summer. The size of the overhang or awning can be calculated for your location from a simple three step procedure: (a) determine the time of year that the window should receive full noontime sunlight (e.g., December 21) and the time of year it should receive no noontime sunlight (e.g., March 21); (b) determine the solar altitude at noon for these two dates; and, (c) calculate the overhang or awning length and the height of the overhang or awning above the window. The overhang length is found by dividing the height of the window by the tangent of the solar altitude at noon on the selected summer date, minus the tangent of the solar altitude at noon on the selected winter date. The answer for this part is the length, or how far the overhang or awning should “stick out” from the building. The height of the overhang or awning above the window can be found by multiplying the overhang length by the tangent of the solar altitude at noon on the selected winter date. 12. Some students may be interested in investigating microclimates on your campus. A map of the microclimates can be prepared by investigating plant growth and taking measurements. The influence of a large city on the climate can be investigated by comparing the temperature, precipitation, and humidity of a city with the surrounding countryside. For Class Discussions 1. An airplane flying at an altitude of 10 km (about 6 mi) is above about how much of the Earth’s atmosphere? About a. 90% b. 70% c. 50% d. 30% 2. The lower part of Earth’s atmosphere is mostly heated by a. the Sun b. Earth c. exhaust from combustion engines. 3. Ozone is a. O b. O2 c. O3 4. Without adding or removing any water vapor, a sample of cooling air will have a relative humidity that is a. increasing. b. decreasing. c. the same. 5. The dew point temperature occurs when a. the relative humidity is 100%. b. condensation begins to form. c. the air becomes saturated. d. any of the above. 6. When air that is saturated is cooled, a. some of the water vapor condenses. b. the relative humidity decreases. c. the capacity of air to hold moisture increases. d. the relative humidity increases to greater than 100%. 7. An air from over the Gulf of Mexico makes which type of air mass? a. continental polar b. maritime polar c. continental tropical d. maritime tropical 8. Which one of the following has more associated stormy weather? a. cold front b. occluded front c. warm front d. stationary front 9. A thunderstorm that occurs at 3 AM is more than likely caused by a. a barrier to moving air. b. a cold front. c. convection. d. a warm front. 10. A hurricane is a tropical cyclone with a wind speed of at least a. 75 km/h (46 mi/h) b. 100 km/h (62mi/h) c. 120 km/h (75 mi/h) d. 100 km/h (15 mi/h) 11. The most violent weather disturbance is a a. tornado. b. thunderstorm. c. hurricane. d. cyclone. 12. Clear, fair weather is usually associated with a(n) a. warm front b. cold front c. cyclone d. anticyclone 13. Is it possible for water vapor to condense in clean, cool air? a. Yes. b. No. 14. Which of the following climatic influences would probably make the temperatures of a city more even? a. high altitude b. low altitude c. large body of water nearby d. surrounded by large areas of land Answers: 1b, 2b, 3c, 4a, 5d, 6a, 7d, 8b, 9b, 10c, 11a, 12d, 13b, 14c. Answers to Questions for Thought 1. The greenhouse effect is caused by certain gases in the atmosphere referred to as greenhouse gases. These gases absorb infrared radiation emitted by the ground and re-radiate this radiation in all directions. Some of this re-emitted radiation is again absorbed by the ground, starting the process over, some is absorbed by other molecules in the atmosphere, increasing the temperature, and some is radiated to outer space. This results in a slowdown of the rate that energy from the Sun escapes into space. Since some of the energy is redirected to the surface, the surface temperature is increased over what it would have been if this effect were not present. As an analogy for this behavior, a greenhouse is misleading. The glass in a greenhouse allows the short wavelength light radiation in but does not allow the heat to escape by convection. The greenhouse gases do not trap the infrared radiation but are involved in a dynamic absorption and emission process. The more greenhouse gases, the more the temperature is increased, but adding more glass layers does not increase the temperature in the greenhouse significantly. 2. The ozone shield protects living things on the surface of Earth by absorbing damaging ultraviolet light. Chemical reactions that occur in this layer of the atmosphere require ultraviolet light. Much of the ultraviolet light passing through this layer is absorbed in these chemical reactions. Chemicals used on the surface of Earth have reached this layer of the atmosphere. They combine with oxygen to form stable compounds; thus, the amount of oxygen available for ozone-forming chemical reactions, which absorb ultraviolet light, is decreasing. The resulting increase in ultraviolet light at Earth’s surface could have serious health consequences and decrease the output of farms. 3. A horizontal movement of air is called wind. Uneven heating of the atmosphere causes warmer, less dense parts of the atmosphere to be pushed up by cooler, denser parts of the atmosphere. Thus the Sun provides the energy to drive the wind. 4. In warmer air, the individual molecules have more kinetic energy and are therefore moving faster. These faster-moving molecules collide more violently until their higher speed drives them apart. Since the molecules are farther apart, there are fewer molecules in a unit volume and so the density is less. 5. Heated air is less dense than cooler air. The cooler, denser air pushes the less dense, more buoyant warm air up as the cooler air sinks. 6. High humidity prevents the addition of water vapor from the evaporation of perspiration to the air. Since the evaporation of perspiration carries heat away, when this evaporation does not take place, individuals feel hotter. 7. Clear nights allow a greater loss of infrared radiation by objects than cloudy nights. The air must be cold and calm to allow the water vapor to condense directly onto objects and freeze. 8. A cloud is a collection of water droplets high in the air. A cloud forms when air containing water vapor is cooled and the water vapor condenses onto dust and other small particles in the air. 9. Atmospheric stability is a measure of how air moved up in the atmosphere will react. In stable air, any air moved upward will tend to return to its former level. This behavior discourages the formation of clouds, and any clouds that do develop are usually arranged in the horizontal layers of stratus-type clouds. In unstable air, any air moved upward will tend to continue rising. Cumulus clouds usually develop in these types of conditions. 10. Coalescence of cloud droplets involves larger, slower-moving cloud droplets colliding and merging with smaller droplets as they fall. This merging process forms raindrops after many collisions. In the ice crystal process, ice crystals capture water molecules and grow to larger sizes while neighboring water droplets are evaporating. As they grow larger and begin to drift toward the surface, they may coalesce with other ice crystals or water droplets. If they fall during the summer, the warm air below melts the crystals to form raindrops. In winter, they reach the ground as snow. 11. An air mass is a large, uniform body of air with nearly the same temperature and moisture conditions throughout. Ordinary air does not necessarily have the same temperature and moisture conditions throughout it. 12. (a) The passage of a warm front has clouds forming far in advance of the ground-level base of the front. These high-level clouds are usually followed by thicker and lower stratus clouds as the front advances. A broad band of drizzle, fog, and continuous light rain usually accompanies these clouds. (b) Towering cumulus clouds accompany a cold front, with intense thunderstorms and a rapid temperature drop occurring as the front passes. A rapid shift in wind direction and a rapid increase in the barometric pressure also mark the passage of a cold front. 13. (a) Clouds and cyclonic storms are associated with low-pressure centers. Obviously, low atmospheric pressure is associated with low-pressure centers as well. In the Northern Hemisphere, inward flowing winds wind around counterclockwise to a low-pressure center. (b) A high-pressure center has outward moving winds that wind around clockwise in the Northern Hemisphere. Higher atmospheric pressures and clear weather are associated with high-pressure centers. 14. A maritime tropical air mass would probably have afternoon thunderstorms. As the land below the mass warms up during the day, the warmer air near the ground would create thermals in which cumulus clouds could develop from the moist air. These clouds could be the source of the afternoon thundershowers. 15. The first stage begins as convection, mountains, or a dense air mass slightly lifts a mass of warm, moist air in an unstable atmosphere. The lifted air mass expands and cools and cumulus clouds form. An updraft is created as the released latent heat of vaporization warms the air. Soon the upward moving saturated air reaches the freezing level and ice crystals and snowflakes begin to form. When they become too large to be supported by the updraft, they begin to fall to the surface, melting into raindrops. The mature stage begins when these drops reach the surface. As the raindrops fall through the air, friction between the falling drops and the cool air produces a downdraft. This mass of air spreads out when it reaches the surface and the leading edge has the appearance of a miniature cold front. This air mass may play a role in creating new cells in front of the thunderstorm. This stage in the life of a thunderstorm has the most intense rainfall, winds, and possibly hail. As the downdraft spreads throughout the cloud, the supply of new moisture is cut off and the thunderstorm enters the final, dissipating stage. 16. A tornado is the smallest, most violent weather disturbance that occurs on Earth. A tornado forms with intense thunderstorms mainly in the spring and early summer afternoons. The states of Texas, Oklahoma, Kansas, and Iowa have the highest incidence of tornadoes. 17. A hurricane is a large, violent circular storm that is born over the warm, tropical ocean near the equator. As a hurricane approaches the air seems unusually calm as a few clouds appear, then thicken as the wind begins to gust. Over the next six hours or so the overall wind speed increases as strong gusts and intense rain showers occur. Thunderstorms, perhaps with tornadoes, and the strongest winds occur just before the winds suddenly die down as the sky clears with the arrival of the eye of the hurricane. It takes the eye about an hour to cross then the thunderstorms and high winds begin again, this time blowing in the opposite direction. 18. Weather is the current condition of the atmosphere. Climate is the larger pattern these weather changes create. “Climate is what you expect, weather is what you get.” 19. Altitude, mountains, large bodies of water, and ocean currents all affect a regional climate. Average air temperature decreases with altitude. Mountains affect the conditions of passing air masses. Generally the eastern slopes of mountain ranges in the Northern Hemisphere are dryer than the western slopes because water precipitated out of the air as it crossed the mountains. Large bodies of water tend to moderate the temperature of a region. Ocean currents can influence the temperature of air masses that move from the water to the land, influencing the temperature on the land. 20. As heated air rises, the lower pressure at higher altitudes allows the air to expand. The work required to accomplish this expansion reduces the energy of the molecules of the air, lowering the air temperature. Since the temperature is now lower than at ground level, snow can exist at higher elevations when it has melted at lower elevations. For Further Analysis 1. Fill a long garden hose with water and cap one end. Place the open end in a bucket of water and support the hose vertically. Standard pressure should support (29.92 inches Hg) 13.6 (density of Hg) = 406.912 inches of water. Divide 406.912 inches of water by 12 inches/foot = 33.9 ft of water. 2. Air expands and cools as it rises. 3. Answers will vary. 4. It is convection that moves air, and differential heating is needed for convection. 5. First, find the current condition of temperature and absolute humidity (found from relative humidity at the current temperature). Place pencil point on the temperature and absolute humidity data point. Move pencil to left until it touches saturation line. Follow this point straight down to the x-axis to read the dew point temperature. 6. Dew (or frost) forms directly on objects and the ground. It does not fall, and this is a requirement to be precipitation. 7. Similarities – Both are changes in the weather conditions. Differences – air mass weather conditions undergo slow, gradual changes; frontal weather conditions undergo rapid, intense changes. 8. A tornado is the smallest most violent weather disturbance on earth, but a hurricane covers significantly more area. In addition, hurricanes can sometimes spawn tornadoes in addition to the damage done by sustained hurricane winds. 9. Answers will vary, but could include regional changes caused by altitude, mountains, large bodies of water, or ocean currents. Chapter 18 Earth's Water Contents Water on Earth Fresh Water Surface Water Groundwater Fresh Water as a Resource A Closer Look: Wastewater Treatment Seawater Oceans and Seas The Nature of Seawater Movement of Seawater Waves Ocean Currents A Closer Look: Rogue Waves The Ocean Floor A Closer Look: Key Forecasting Tool for the Chesapeake Bay Overview Unlike other planets, Earth has so much water on the surface that it appears blue when viewed from space. Most of this water, however, is salty ocean water that covers about 70 percent of the surface. Available water that is not salty, called fresh water, makes up less than 1 percent of all the water on Earth. Precipitation is the source of almost all the fresh water found in streams, in lakes, and underground. Each year, about one meter of water falls to the surface when averaged over the whole Earth. About a meter of water is also evaporated into the atmosphere from the surface each year. Fresh water is available because the amounts precipitated and evaporated differ over land and the oceans. The amount evaporated and precipitated varies from location to location, but on the average, more water is precipitated over land than is evaporated from it. This excess of ocean-derived precipitation eventually returns to the ocean to complete the water cycle. Demand for fresh water will increase in the future, which may cause shortages in some areas with limited water supplies. The surface and groundwater supplies of fresh water are moving, so they cannot be conserved by nonuse. What is needed is a balance between use and recharge. Supplies of fresh water can be increased by building storage reservoirs, manipulation of the weather, recycling water, and conversion of salt water to fresh water. Many people point to the ocean, the prevalent environment of Earth's surface, as the answer to water, food, and other needs of our growing population. If the population continues to increase, and if resources of the land continue to become depleted, it seems reasonable to expect that the ocean will be used to provide more and more of humanity's needs. Much remains to be learned about the ocean and the circulation of ocean water, however, and there is concern that the present practice of using the ocean as a convenient place for dumping wastes may cause serious problems on a long-term basis. Suggestions 1. Demonstrate the distribution of Earth's water by showing a 40-liter aquarium filled with water to represent all the water of Earth. Remove 968 mL to a l liter container to represent all the fresh water on Earth. The water remaining in the aquarium represents all the salt water of the oceans. To illustrate how the fresh water is distributed, place three 250-mL containers and a medicine dropper in front of the 1-liter container. Pour 760 mL from the “fresh water” container into one of the small containers to represent the amount of fresh water locked up in ice. Pour 200 mL into a second container to represent the amount of fresh water that is underground. Pour the remaining 8 mL into the third container to represent the water in all the rivers, streams, and lakes of the world. A medicine dropper with about three-quarters of a drop from the third container will represent how much water is in the atmosphere at a given time. 2. Use a 250 mL beaker full of marbles to illustrate the concept of porosity. The porosity of the container of marbles is the measured amount of water that you can pour into the beaker divided by the volume of marbles multiplied by 100. Show the porosity of a brick by measuring the mass of a dry brick, then measuring it again after the brick has soaked in a container of water for some time. 3. In addition to problems of pollution and the cost of cleaning water supplies, the study of fresh water provides many opportunities for discussion of difficult social issues. For example, a new reservoir constructed on a river can provide economic benefits, an increased water supply, new recreational areas, and electric power. On the other hand, construction of the reservoir can displace people and wildlife, destroy areas of scenic beauty by covering them with water, and change the environment. Other social issues concerning water include the question of who should have the right to existing water supplies—farmers, who need water to grow food; industries, which need water for jobs, producing energy and products that people need; or cities, which need water for domestic use by people for cooking, cleaning, washing, and everyday consumption. 4. Using a map showing the major ocean currents, students could predict where a bottle with a message inside might be expected to be found after a week, a month, and a year. 5. Watch for news reports that illustrate how humans are changing the oceans. Examples are ocean waste dumping, oil-well drilling, oil-tanker accidents, coastal city waste disposal, and landfills for development. For Class Discussions 1. Generally, most of the freshwater supply is obtained from a. streams or lakes. b. groundwater. c. the ocean. 2. If water is in short supply, who should have first priority for use? a. agriculture b. city domestic use c. industries d. The answer is controversial. 3. How many separate, independent oceans are found on Earth? a. 1 b. 5 c. 7 d. 10 4. What is the origin of all the seawater on Earth? a. Accumulated rainwater over the years. b. It formed soon after the Earth. c. Outer space, by way of comets. d. Volcanoes. 5. How has the composition of seawater changes after millions of years of rainfall, evaporation, and more rainfall? a. Fresh in the beginning, increasing in salinity throughout history. b. It has changed very little. c. The salinity has decreased ever since the last ice age. d. The salinity of seawater varies for ocean to ocean, depending on the location. 6. The flow rate of all of the ocean currents in the world must be equal? a. Yes. b. No. 7. Which one of the following does not belong with the others? a. Gulf Stream. b. California Current. c. Labrador Current. 8. Where does the ocean basin begin? a. At the beach. b. End of continental shelf. c. Beyond continental slope. d. Bottom of submarine canyon. Answers: 1a, 2d, 3a, 4b, 5b, 6a (sealevel does not change), 7a (warm other cold; also called a stream), 8c. Answers to Questions for Thought 1. Water that falls on land either evaporates, flows downhill to a lower place, or soaks into the ground. 2. The flow of a stream comes from the groundwater that has seeped into the channel. 3. The water table is the boundary between the zone of saturation and the zone above it. A hole that is drilled to the water table is a well. Holes not drilled this far are not wells and do not have groundwater collect in them. Water only accumulates in the portion of the well below the water table. 4. (a) Surface water contains more sediments, bacteria, and possible pollutants than groundwater because it is more active and is directly exposed to the atmosphere. Its higher treatment cost is offset because it is more readily available, but it can be very sensitive to precipitation amounts. (b) Groundwater is naturally filtered as it moves through the pore spaces of an aquifer, so it usually does not need to be filtered. It must be pumped up to the surface, and the energy required for this pumping could be expensive. Dissolved minerals that are usually present in groundwater also may require treatment. 5. Arguments may vary. (a) Agricultural interests claim that they should have priority because they produce the food and fibers that people must have. (b) Industries maintain that they need priority because they create jobs and products that people must have. (c) Cities claim that domestic consumption is most important because people cannot survive without water. 6. Possible ways of extending the freshwater supply include recycling wastewater or desalinating water from the ocean. One of the more radical ideas is to tow icebergs from the polar regions to regions that need water. Conservation is an easily applied method to stretch existing water supplies. 7. Natural processes remove dissolved materials as quickly as the rivers add them. Calcium and silicon are removed by plants and animals to make solid shell, bones, and other hard parts. Other dissolved minerals form solid deposits directly and also make sediments that settle to the ocean floor. These solid deposits and the hard parts of animals and plants are recycled into Earth's interior along with the solid sediments deposited by rivers. 8. Regular groups of low profile, long-wavelength waves are called swell. They form initially in a storm as a chaotic, superimposed mixture of waves. As the waves travel away from the storm area, the longer wavelengths travel faster and last longer than the shorter wavelengths. The longer wavelengths eventually travel alone as a swell. 9. Refraction caused by the shallow water near the shore causes the waves to approach the shore head-on. The part of the wave in the shallower portion refracts because it is traveling slower than the rest of the wave. The circular motion of the water particles reaches the bottom when the depth is about half a wavelength, and friction with the bottom is what slows the shallower end of the wave. This slowdown allows the part of the wave farther from shore to catch up and forces the wave to become parallel to the shore. 10. Wind speed, the length of time the wind blows, and the fetch, or the distance over which the wind blows all affect the formation of waves. Larger waves are produced by strong winds that blow for a long time over a long fetch. In general, longer blowing, stronger winds produce waves with greater wave heights, longer wavelengths, and longer periods, but a given wind produces waves with a wide range of sizes and speeds. 11. As water waves approach the shore, the bottom of the wave begins to reach the bottom. Friction between the moving particles of water at the bottom of the wave and the bottom result in a slower-moving wave as the wave height increases. The wave front becomes progressively steeper as the bottom part of the wave moves slower than the top. Eventually the top part becomes so steep that it breaks forward and becomes a breaker. The zone where breakers occur is called surf. 12. Water accumulated on shore returns to the ocean by moving beneath the breakers. This weak current might be pushed along the shore by the waves. If the current finds a lower place or channel deeper than the adjacent bottom, a strong stream of water called a rip current bursts out against the waves and returns water through the surf to the sea. A lack of surf, darker-looking waters indicating a deeper channel, and a turbid or muddy streak of water indicate the presence of a rip current. 13. On average, about 98 percent of Earth’s water exists as liquid, about 2 percent as ice, and a fraction of a percent as water vapor. Over 97 percent of the water is stored in the oceans as salt water, and about two-thirds of the fresh water is locked up in the ice caps of Greenland and the Antarctic and in glaciers. Less than 1 percent of all water on Earth is available as liquid fresh water. 14. An artesian aquifer has groundwater that is under pressure because the groundwater is confined between two impermeable layers and has a recharge area at a higher elevation. The pressure will cause the water to rise in a well drilled into the aquifer, becoming a flowing well if the pressure is high enough. 15. Water particles are moved in a circular motion by a wave passing in the open ocean. On the surface, a water particle traces out a circle with a diameter that is equal to the wave height. The diameters of the circles traced out by water particles decrease with depth to a depth that is equal to one-half the wavelength of the ocean wave. Bottom sediment cannot be moved by waves when the sediment is below the wave base. For Further Analysis 1. Answers will vary, but could include such ideas as towing glaciers or purifying seawater through the use of solar energy. 2. Answers will vary, but could include such ideas as building retention basins where runoff will soak into the ground. 3. Answers will vary, but the two letters should both be convincing. 4. The oceans are well mixed and there are chemical processes at work that remove dissolved materials. 5. Answers will vary. Chapter 19 Organic and Biochemistry Contents Part I The Nature of Organic Compounds Organic Chemistry Hydrocarbons Hydrocarbons with Double or Triple Bonds Hydrocarbons that Form Rings Petroleum Hydrocarbon Derivatives Functional Groups Generate Variety Alcohols Ethers, Aldehydes, and Ketones Organic Acids and Esters Synthetic Polymers A Closer Look: Nonpersistent and Persistent Organic Pollutants Part II Organic Compounds of Life Organisms and their macromolecules Carbohydrates A Closer Look: So You Don’t Eat Meat! How to Stay Healthy Proteins A Closer Look: Some interesting Amino Acid Information Nucleic Acids Lipids A Closer Look: Omega Fatty Acids and Your Diet A Closer Look: Fat and Your Diet Overview The ubiquitousness of organic compounds should be stressed to students in introducing organic chemistry. It should be pointed out, for example, that the gas, coal, and oil used by our society are all organic compounds. The trees and plants of the forested lands of the earth are also made of organic compounds. Indeed, all animals (including humans) are made up of organic compounds. A very strong case can be made for oil and coal not being used as fuel because they are such marvelous sources of the types of organic compounds needed in our technological society. Various organic compounds of special interest to students have been included in this chapter. These compounds are used as examples of the classes of hydrocarbon derivatives —alcohols, ethers, aldehydes, ketones, organic acids, and esters. The particular structures are included in the various classes of derivatives to act as attention-getting subjects that will give students greater reason to familiarize themselves with that particular group of organic compounds. For instance, considerable interest can be generated in the classroom by considering the various kinds and types of alcohols and what happens when a bottle of wine “goes bad.” There can be interest in the organic compounds of insect stings and why they hurt. Many are usually interested in the esters responsible for the aroma and flavor of fruit and for the aroma of roses and lilacs. Synthetic polymers, the many types of plastics, and synthetic fibers in use in our society today are also topics of special interest to students, including the environmental problems created by the plastics. The importance of bond orientation in chemical compounds can be stressed by pointing out the relatively small difference in the way that the glucose molecules of starch and cellulose are linked. Also to be stressed is the tremendous difference in the chemical and physical properties of starch and cellulose because of the different way in which the glucose units are chemically bound together. The second part of the chapter contains information that relates to the organic compounds of life, i.e., carbohydrates, lipids, proteins, and the nucleic acids. Be sure to link these with the more traditional discussion of organic molecules used earlier in the chapter. Suggestions 1. Ask students to list and/or collect various organic compounds available in today's home. Remind students that organic compounds are present in many places in the home rather than just in the kitchen. 2. The distinguishing characteristics of organic acids, alcohols, and esters can be contrasted with those of inorganic acids, bases, and salts. 3. The distillates from crude oil and their physical differences make an interesting display for students to observe. You can obtain a sample of crude oil by writing public relations officers of the major oil companies if there is not a local source. The distillates should be sealed in airtight containers to retard evaporation. 4. To illustrate the carbon content in an organic compound, add a sufficient amount of concentrated sulfuric acid to cover the surface of about 100 g of granular sugar that is poured into a beaker. Stir the mixture with a glass rod until a color change appears, then watch the black column of carbon rise above the beaker. Obnoxious odors are produced by this reaction, so use a fume hood, perform the demonstration outside, or display only the result of the reaction to the class. 5. Additional demonstrations: (a) Generate ethylene gas by cautiously boiling 25 mL C2H5OH with 80 mL concentrated H2SO4. Boil the mixture with boiling chips in a Florence flask on a ring stand that is fitted with a thistle tube and gas collection tube in a two-hole stopper. Collect the gas by water displacement, gradually adding all the acid to the thistle tube as you gently boil the mixture. Add an inverted bottle of ethylene to a plastic bag with unripe fruit. (b) Show a few of the esters produced when an alcohol reacts with an acid. (1) In a test, heat 2 mL butyric acid, 2 mL ethyl alcohol, and 1 mL concentrated H2SO4 (dehydrating agent). Ethyl bute rate should form, which has the odor of pineapples. (2) To produce amyl acetate, heat 5 mL acetic acid, 3 mL amyl alcohol, and 1 mL concentrated H2SO4. Amyl acetate has the odor of bananas. For Class Discussions 1. Carbon atoms can form so many different organic compounds because they a. can combine with up to four other carbon atoms as well as other kinds of atoms. b. form covalent bonds by sharing electrons. c. are easily decomposed by heat. d. have a tetrahedral molecular shape. 2. Compounds with the same molecular formulas but different structures are known as a. polymers. b. isotopes. c. isomers. d. polytopes. 3. Which one of the following is a correct name for this hydrocarbon? a. Methane b. Heptane c. Octane d. Kerosene 4. Of the following, the most stable is a. C2H6 b. C2H4 c. C2H2 d. none of the above 5. Of the following, which is most likely to be found in gasoline? a. CH4 b. C7H16 c. C14H30 d. C16H34 6. Jet fuel, kerosene, coal oil, and lamp oil are names for the same group of hydrocarbons. a. Yes. b. No. 7. All of the different kinds of alcohols a. have either one, two, or three OH functional groups. b. are safe to drink. c. are denatured. d. have one OH functional group. 8. The building blocks of all proteins are a. monosaccharides. b. esters. c. amino acids. d. triglycerides. 9. Polyunsaturated oils are oils that a. have room for more cholesterol. b. have a higher number of units with double bonds. c. are dry oils, containing no water. d. are used in the manufacture of polymers. 10. Synthetic polymers that are variations of ethylene-derived monomers are manufactured from a. fruit extracts, such as citrus fruit skins. b. fermentation reactions. c. fossil fuels. d. formaldehyde Answers: 1a, 2c, 3b, 4a (ethane is saturated), 5b, 6a, 7d, 8c, 9b, 10c. Answers to Questions for Thought Part I 1. A compound with carbon as its principal element is defined as an organic compound. 2. Carbon's valence of four allows it to link up with four other carbon atoms, or a wide range of other kinds of atoms, allowing for an almost limitless range of combinations. 3. Ethane has only one structure because it has so few atoms, so it does not have any isomers. 4. Ethylene has a double carbon bond that can be broken to provide sites for single covalent bonds to join the ethylene units. Ethane is an alkane, so it does not have a double carbon bond to break to allow it to form long chains. 5. Each of the four bondable electrons in a carbon atom inhabits an area as far away from the other three as possible. Carbon can share with four other atoms at each of these sites. 6. (a) Natural gas is a mixture of hydrocarbon gases, mostly methane. (b) LPG is liquefied propane or butane. (c) Diesel fuel is a mixture of a group of hydrocarbons that have from fifteen to eighteen carbon atoms per molecule. 7. The octane number scale describes the burning rate of gasoline. The scale is based on pure n-heptane, straight-chain molecules that are assigned an octane number of 0, and a multiple branched isomer of octane, 2,2,4-trimethylpentane, which is assigned an octane number of 100. The “cracking and reforming” process used to increase the octane in unleaded gasoline is more expensive than simply adding a lead compound to the gasoline to increase its octane number. 8. A polymer is a long chain of repeating molecular units. Cellulose is a polymer formed naturally in plants. Polyethylene is a synthetically produced polymer. Part II 9. Carbohydrates – example: table sugar, wood Proteins – example: hair or enzymes Nucleic acids – example: DNA, genetic material in humans Lipids – example: lard, oil For the structural formula of linoleic acid see figure 18.23. Linoleic acid is an unsaturated fatty acid because it has double bonds between carbons atoms in the chain. 10. A functional group is the atom or group of atoms in an organic molecule that is the site of a chemical reaction. Functional groups are chemically active because they have multiple bonds that can be broken in order to have chemical reactions, or because they have lone pairs of electrons that can participate in reactions. Examples include: a) ROH alcohol group, 2) ROR' ether group, 3) RCOOH organic acid group, 4) RNH2 Amine group. 11. The double bonds within the molecule make this an unsaturated fatty acid. 12. The “sugar” referred to in the advertising is sucrose, or table sugar. Dextrose and fructose are classified as simple sugars. Corn syrup is mostly glucose, which is also called dextrose. The advertising is therefore misleading, because the ingredients are sugars even if they are not table sugar. 13. Micromolecule are usually inorganic and smaller than organic molecules which are considered to be macro (large) molecules. 14. 15. The main roles played by protein are Structural support Regulation of metabolic activities Carrier molecules Catalysts Invitation To Inquiry 1. What is the earliest date for which there is evidence for the production of ethyl alcohol? It appears that fermentation for the production of alcohol dates back to approximately 6000 BC. 2. In which culture did they occur? Counties in the Far East such as Egypt and Iran. 3. What is the molecular formula and structure of ethanol? 4. Do alcohol and water mix? Yes, but only to a certain degree. 5. How much ethanol is consumed in the form of beverages in the United States each year? Answer will vary depending on the source of information. 6. What is the legal limit to be considered intoxicated in your state? Answer will vary depending on the source of information. 7. How is this level measured? Answer will vary depending on the source of information. 8. Why is there a tax on alcoholic beverages? Answer will vary depending on the source of information. 9. How do the negative effects of drinking alcohol compare between men and women? Usually, men can tolerate more than women can. 10. Have researchers demonstrated any beneficial effects of drinking alcohol? Yes, it is estimated that two drinks for men and one drink for women each day lowers blood pressure. For Further Analysis 1. Many people feel that by using a higher octane gasoline in their vehicles that they will get “better performance.” What is the difference between high octane and regular gasoline? The amount of octane will vary depending on the gasoline investigated. Does scientific evidence bear this out? The octane rating of an engine depends on the manufactures recommendation. In certain situations, the answer is yes. What octane gasoline is recommended for your vehicle? Answer will vary depending on the engine. 2. There have been some health concerns about the “additives” used in gasoline. What are these additives? Most gasoline contains MMT (methylcyclopentadienyl manganese tricarbonyl). What purpose does It serve? It Is an octane enhancer. What do opponents of using such additives proposed are its negative impact? It is thought that the manganese may be detrimental to health. 3. The so-called “birth control pill,” or “the pill,” has been around since the early 1960s. This medication is composed of a variety of organic molecules. What is the nature of these compounds? The “pill” contains hormones that are members of the lipid group known as steroids. How do they work to control conception since they do not control birth? These hormones at the proper concentration prevent ovuation. What are some of the negative “side effects” and what are some of the related benefits of taking “the pill?” Increased risk of blood clots, stroke and heart attack. 4. Many communities throughout the world are involved in recycling. One of the most important classes of materials recycled is “plastic.” There has been concern that the cost recycling plastics is higher than the cost of making new plastic products. Go to the Internet and a. Identify the kinds of 'plastics' that are commonly recycled. b. Explain how a plastic such as HDPE is recycled. c. Present an argument for 1. Eliminating the recycling of HDPE 2. Expanding the recycling of HDPE. Answers will vary. Chapter 20 The Nature of Living Things Contents Part I: The Characteristics of Life What Makes Something Alive? The Cell Theory Cell Membranes Getting Through Membranes Diffusion Osmosis Controlled Methods of Transporting Molecules Organelles Composed of Membranes Nonmembranous Organelles Nuclear Components Major Cell Types The Prokaryotic Cell Structure A Closer Look: How we are Related A Closer Look: Antibiotics and Cell Structural Differences The Eukaryotic Cell Structure Part II: Energy Transformations in Cells Respiration and Photosynthesis The Energy Transfer Molecules of Living Things—ATP Aerobic Cellular Respiration Photosynthesis Part III: Cellular Reproduction The Importance of Cell Division The Cell Cycle A Closer Look: Stem Cells The Stages of Mitosis A Closer Look: Abnormal Cell Division: Cancer Overview The chapter begins by focusing on characteristics typical of living things, and then describes the basics of the cell theory. When presenting mitosis, we include the names of the stages and the events that occur during the stages. The most important material, however, considers the unique result and the significance of this result; the fact that the daughter cells have exact copies of the genetic information of the parent cell preponderates the stages of the process. Our teaching efforts and tests should reflect this. Although it is easy to test for the stages of mitosis, try not to compromise importance for facility. For Class Discussions 1. Which is not a characteristic of all life? a. responsiveness b. evolution c. reproduction d. random cell structure 2. All of the chemical reactions within your body are called your a. life b. metabolism c. astrology d. heredity 3. Protoplasm is all the living material a. that makes up a cell. b. inside the cell membrane except the nucleus. c. inside the nucleus. d. inside the cell except the protein material. 4. Eukaryotic cells are found in A. fungi. b. plants. c. animals. d. All of these answers are true. 5. An outside source of energy (ATP) is required for a. osmosis. b. diffusion. c. active transport. d. None of these answers are true. 6. The most important result of mitosis is the a. production of new varieties of cells to meet changes in the environment. b. exact duplication of the parent cell's genetic information. c. equal division of parent cell's genetic information between the two daughter cells. d. equal distribution of the parent's cytoplasm between the two daughter cells. 7. After cell division, some cells become differentiated. This means that they a. become different shapes. b. become different sizes. c. perform different functions. d. become different in all these ways. 8. The time it takes for cells to divide a. varies, but it takes sophisticated equipment to measure this small difference. b. depends on the health and environment of the cell. c. does not vary at all but is controlled by an internal clock. d. varies widely and unpredictably in cells of the same local area of the same organism during any specific time period. 9. The order in which the stages of mitosis proceed is a. anaphase, interphase, metaphase, prophase, telophase. b. interphase, anaphase, metaphase, prophase, telophase. c. prophase, metaphase, anaphase, telophase, interphase. d. interphase, telophase, prophase, anaphase, metaphase. 10. The normal purpose of mitosis is a. to make cells smaller b. to produce genetically identical copies of cells c. to make additional DNA d. differentiation Answers: 1d, 2b, 3a, 4d, 5c, 6b, 7d, 8b, 9c, 10b Answers to Questions for Thought Part I 1.
Structure Chloroplast Endoplasmic reticulum Golgi apparatus Lysosome Mitochondria Nucleus Function Photosynthesis Transport of materials, sites for protein synthesis Secretion Contains digestive enzymes Site of cell respiration Control center for the cell
2. Diffusion is the movement of molecules as a result of their energy. Osmosis is the diffusion of water through a differentially permeable membrane. Active transport involves energy supplied by the cell to move molecules from an area of low concentration to an area of high concentration. Facilitated diffusion is movement in the direction from higher to lower concentration but aided by the presence of a carrier molecule. 3.
Cell wall Relatively rigid and thick Composed of many materials but often contains cellulose Cell membrane Very thin and flexible Composed of lipid and protein
4. Proteins: Nucleus, all membranes, lysosomes, mitochondria, and chloroplasts Nucleic acids: Chromatin of nucleus, ribosomes, and nucleolus Carbohydrates: Cytoplasm and cell wall 5. If the eye preparations were not isotonic they either cause the cell of the eye to swell or shrink. Part II 6. Each contains just the right amount of energy to power the job. When the power has been drained, it can be recharged numerous times before it must be recycled. 7. It a series of enzyme-controlled reactions that takes place in the cytoplasm of cells and results in the breakdown of glucose with the release of electrons and the formation of ATP. The electrons are sent to the electron-transport system (ETS) for processing. 8. The electrons are transferred through a series of oxidation- reduction reactions known as the electron transport system involving enzymes until eventually, the electrons are accepted by oxygen atoms to form oxygen ions (O-2)The negatively charged oxygen atoms attract two positively charged hydrogen ions to form water (H 2O). 9.
Glycolysis Cytoplasm
Krebs Mitochondria
ETS Mitochondria
10. Light-capturing, Light-dependent reactions. The light-independent reactions will continue as long as the first two reaction sequences have provided enough products. Part III 11. Prophase: The individual chromosomes become visible, duplication of centrioles, spindle begins to form, nuclear membrane disintegrates, and nucleoli disappear. Metaphase: Chromosomes align at the equatorial plane, no nucleus is present, and spindle formation is completed. Anaphase: Nuclear membrane still absent, spindle extends from pole to pole, chromosome splits at the centromere, and daughter chromosomes move to separate poles. Telophase: Daughter nuclei are formed, nucleoli reappear, and cytokinesis occurs. 12. The life of a cell: gap phase one, synthesis, gap phase two, and cell division. 13. DNA replication occurs during interphase. 14. DNA is never visible in the sense that one can directly see it. Even in the electron microscope, one sees only plating or covering of some metal on what was the DNA. Since it is an important part of chromosomes, the question is really asking when are the chromosomes most visible? The answer is metaphase. Chromosomes are most distinct at this stage and most easily counted. 15. The centrioles move away from one another to opposite ends of the cell, forming the cell’s poles and spindle fibers form and grow from one pole to another. As the spindle fibers shorten they cause the chromatids to separate. Invitation To Inquiry 1. What are the four generally recognized types of chemotherapeutic drugs? A) Antimetabolites, B) topoisomerase inhibitors, C) Alkylating agents, D) Plant alkaloids. 2. What is the mechanism of action of each of these types of anticancer treatments? Antimetabolites appear to the cancer cell as a normal nutrient, but in reality it is a compound that will fatally interfere with the cell’s metabolic pathways. Methotrexate appears to be the normal substrate for an enzymatic reaction required to produce the nitrogenous bases adenine and guanine. When this medication is given, cancer cells are prevented from synthesizing new DNA. Topoisomerase inhibitors are drugs that prevent the DNA of cancer cells from “unzipping” so that DNA replication can occur. Doxorubicin is such a medication. Alkylating agents such as cyclophosphamide and chlorambucil form chemical bonds within the DNA of cancer cells resulting in breaks and other damage that is not easily repaired. The plant alkaloids such as vinblastine disrupt the spindle apparatus, thus disrupting the normal separation of chromatids at the time of anaphase. 3. What kinds of side effects might occur in a person on such therapy? Loss of hair, anemia, liver damage, and many others 4. What kind of evidence must a drug company provide to the government before a new anticancer drug is introduced? Answer will vary depending on the nature of the medication. Usually, the company must demonstrate efficacy, limited side effects, and reasonable cost. 5. What are the success rates for the various therapies? Anser will vary depending on the therapy. 6. Why do some people loose their hair after undergoing cancer treatment? Some cancer therapies such as radiation indiscriminately targets actively dividing cells such as those that are active in the hair follicles. For Further Analysis 1. Some people believe that the common cold can be controlled by using the same antibiotics that are used to control infections such as strep throat. What is the true story? Most medications termed antibiotics have as their target bacteria. Virus are not bacterial and therefore do not respond to such treatment. 2. Local community blood programs are always seeking donors. They want to collect whole blood, red blood cells, and platelets from donors. How do these differ from one another? Whole blood is the fluid tissue that comes directly from the circulatory system. Red blood cells are the non-nucleated cells responsible for the transport of O2. Platelets are specialized fragments of certain blood cells actively involved in the clotting process. What is the value and application for each in a medical situation? Depending on the amount of blood lost, whole blood may be used as a replacement. Red cells are valuable when there is a need to replenish in cases of hemolytic disease. Platelets can be isolated from donors are supplied to patients who have lost theirs due to certain kinds of cancer and other diseases. 3. The sources of red and white blood cells are undifferentiated cells called stem cells. There is currently a great controversy about the source and use of these cells for research and medical purposes. What is the nature of the controversy? If the stem cells are derived from embryonic tissue, opponents claim that separating them from the embryonic mass is actually the destruction of a human life. What kinds of abnormalities are associated with stem cells? Stem cells have the ability to become any type of specialized cell in the body. There might be used to replenish the bone marrow responsible for the continuous production of white and red blood cells. To what medical purposes might these cells be used? Should stem cell replacement be successful, patients who have lost their various stem cells due to disease may have them replaced by donor stem cells. 4. Cancer occurs when there is a problem with controlling how cells divide and replace themselves. A tumor forms when cells divide in an unregulated manner. As a tumor grows, some of its cells may change and move out of the tumor, enter the circulatory system, and establish new tumors in other places. Scientists are starting to understand how cell growth is regulated. The picture that is emerging from this research is that many proteins are involved in cell growth regulation. When certain changes occur in the proteins (i.e., histones) that regulate the cell’s growth, the cell might divide when it should not. Sometimes these mutations are inherited as in cervical cancer. Individuals with these mutations are more likely than others to develop cancer. Sometimes these mutations occur because of a viral infection such as Human Papilloma Virus, HPV. Instructor Manual for Integrated Science Bill W. Tillery, Eldon D. Enger , Frederick C. Ross 9780073512259
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