The Atmosphere and its Layers

How does the melodic line affect directs on Earth? What is Earths atmosphere represent of? How do draw and density vary with altitude? What ar the characteristics of the major forms of the atmosphere? Important Terms atmosphere alarm impel barometer troposphere weather condition stratosphere ozone shape mesosphere troposphere Ionosphere aurora At 8848 meters (29,030 feet) to a higher place sea level, Mount Everest Is the highest circumstances in the world. In 1952 Edmund Hillary, a New Zealand mountaineer, and TentingNorway, a mountain extend from Nepal, became the first humans to reach the top. The climb was real dangerous for some(a)(prenominal) reasons, including the extremely low temperature and low level of group O at the summit. When they in the end made it to the top, the two men cheered and embraced. Then Hillary did something to prove a read ?he took withdraw his atomic number 8 mask. He wanted to show that a person could stay alive while breathing natu rally at that high altitude. But after a few minutes, his flock began to fail. When Hillary replaced his mask, his vision improved. Then the two men started back down the mountain.Why did Hillary and Tenting quest to carry type O to the top of Mount Everest? And why was It so crisp there? The answers to these questions depend on how the alarm around Earth changes with altitude. Earths protective(p) Layer What you commonly call agate line, scientists call the atmosphere. The atmosphere (at mum safer) is the layer of gases that surrounds Earth. The atmosphere forms a protective landmark between Earth and spot and provides conditions that are suitable for life. The atmosphere protects Earths scrape up from continual pounding by meteoroids, chunks of rock and metal from space.The atmosphere likewise protects Earth from much f the high-voltage shaft of light therapy from space. The atmosphere holds in heat and helps to moderate Earths temperatures. Without the atmosphere, Eart hs surface would be sympathetic to the moons, boiling hot during the day and freezing gelid at night. Earths relatively constant temperatures allow life to flourish. The atmosphere also provides the gases that are essential for life. Carbon dioxide In the atmosphere Is essential for plants and some other organisms to carry out photosynthesis. Photosynthesis Is the process of capturing the suns energy to make food.Oxygen Is produced during photosynthesis and released into the atmosphere. Your remains intentions oxygen to carry The atmosphere is a mixture of different gases. The reputation of the atmosphere is f assembly linely uniform up to an altitude of virtually 80 kilometers. Earths atmosphere is a mixture of nitrogen, oxygen, water vapor, and many other gases, in which tiny solid and liquid particles are suspended. As Figure 2 shows, two gases?nitrogen and oxygen?make up much than 99 percent of clean, dry business. The amount of water vapor in behavior varies from 0. 02 percent in cold, dry tonal pattern to more than 4. Percent in warm, moist air. Various amounts of water droplets and solid particles are suspended in the atmosphere. Some solid particles drop be seen as floating dust, yet most particles are microscopic. These solid particles come from various sources, including smoke from fires, ash tree and dust from vol quite a littleic eruptions, and salt from ocean spray. course Pressure The atmosphere has weight because of Earths gravity. As a result of this weight, the atmosphere exerts contract. Recall that pressure is the force exerted on a surface divided by the field of operations over which the force is exerted.Air pressure is the force exerted by the weight of a tower of air on a surface. At sea level, air pressure is closely 101 ,325 Newtons per square meter, more commonly explicit as 1013. 5 milliners. One Millard equals 100 Newtons per square meter. Effect of Altitude. Air pressure changes with altitude. The atmosphere is gr ievousst near Earths surface and becomes less dense as altitude increases, as shown in Figure 3. Why is this? Air can be compressed, as it is when you pump air into a tire or a basketball. Near Earths surface, the column of air includes the entire depth of the atmosphere, so the pressure and density are high.As altitude increases, the depth of the column of air above decreases, so the pressure decreases. At high altitudes there is very little air in the column above, so air pressure is lower. As altitude increases, air pressure and density decrease. About one-half of the total mass of the atmosphere is found below an altitude of 5. 6 kilometers. When Hillary and Tenting climbed Mount Everest, they went well above this halfway point. As they climbed, the air became less dense. Hillary had trouble breathing without an oxygen mask because there were fewer oxygen molecules per cubic meter of air at the summit than at sea level.Measuring Air Pressure. Scientists measure air pressure wit h an instrument called a barometer. The first barometer was invented in 1643 by the Italian scientist Evangelists Torricellis. Torricellis invented a hydrargyrum barometer, similar to the one shown in Figure 4. As air pressure increases, the column of mercury in the barometer rises. As air pressure decreases, the column of mercury falls. Thus, a measurement of the height of a column of mercury is a measurement of air pressure. At sea level, the medium air pressure is about 760 millimeters of mercury or, more commonly, 29. 2 inches of mercury. An aneroid (an uh rood) barometer is a smaller, more portable type of barometer. The word aneroid means not development liquid. Aneroid barometers use a metal chamber that expands and contracts with changes in air pressure. Temperature changes dramatically as you move up from Earths surface high into the atmosphere. Scientists use variations in temperature to divide the atmosphere into four vertical layers. The four layers of the atmosphere are the troposphere, the stratosphere, the mesosphere, and the troposphere. The Troposphere.You, along with many other living things, live in the layer of the atmosphere called the troposphere. The troposphere (troth pup safer) is the lowest layer of Earths atmosphere. This layer contains well-nigh all of the atmospheres water vapor and suspended particles, which are beta in the formation of clouds and reciprocation. Most weather takes place in the troposphere. Weather is the condition of the atmosphere in a particular place at a particular time. The height of the troposphere ranges from about 9 kilometers above the poles to 16 kilometers above the tropics.The average height of the troposphere is about 12 kilometers. In the troposphere, temperature generally decreases as altitude increases. Though it varies somewhat, the rate of decrease averages about 6. 5 Celsius degrees per kilometer. For example, if it is ICC where you are on Earths surface, then it is probably about ICC at an altitude of 2 kilometers above you. This characteristic of the troposphere accounts for the extremely low temperatures that Hillary and Tenting had to withstand when they scaly Mount Everest. The Stratosphere. Above the troposphere, as shown in Figure 5, is the stratosphere.The stratosphere (strata uh safer) extends from an altitude of about 12 kilometers to about 50 kilometers. The temperature of the stratosphere remains nearly the same from the bourne with the troposphere to an altitude of about 20 kilometers. Above that height, temperature increases as altitude increases. The temperature in the lower stratosphere remains about -ICC. Above 20 kilometers, the temperature rises to about COCO. The velocity stratosphere is warmer than the lower stratosphere because of the presence of the ozone layer, a region of high ozone concentration.Recall that ozone is a highly reactive gas whose molecules are composed of three oxygen atoms (03). Most of the oxygen molecules you breathe are co mposed of two oxygen atoms (02). In the stratosphere, the energy of sunlight is great enough to split 02 molecules into angiotensin converting enzyme oxygen atoms (O). When an oxygen atom (O) collides with a molecule of oxygen (02), ozone (03) is formed. Ozone absorbs invisible (XIV) radiation syndrome in sunlight and filters such(prenominal) of it out before such radiation can reach Earths surface. The energy absorbed from UP radiation is converted into thermal energy, warming the upper stratosphere.Because UP radiation can be harmful to living things, the presence of the ozone layer is extremely important to life on Earth. In humans, I-JP radiation can cause a deadly form of skin cancer. Certain chemical pollutants have been depleting ozone in the stratosphere, permitting more UP radiation to reach Earths surface. However, the release of such chemicals was express mail by international agreements and national policies adopted in the sass. As a result, ozone levels in the strat osphere appear to have stabilized. The Mesosphere. The layer above the stratosphere is the 50 kilometers and extends to about 80 kilometers.In the mesosphere, temperature decreases as altitude increases. At the top of the mesosphere, the temperature approaches -ICC. The air is very thin in the mesosphere. Studies in the sass discovered that air in this layer may move at speeds of more than 320 kilometers per hour. Most meteoroids that attain the atmosphere burn up in the mesosphere. The Troposphere. The outermost layer of the atmosphere, the troposphere (thru mummy freer), begins at an altitude of about 80 kilometers and extends outward into space. No boundary marks the end of the atmosphere.Instead, the thin air of the troposphere gradually merges with space. In the troposphere, temperature increases chop-chop with altitude, from about -ICC to more than 10000C. Recall from physics that temperature is a measure of the average kinetic energy of molecules. Because gas molecules in the troposphere absorb solar radiation and move very fast, the temperature is quite high. The Ionosphere. The ionosphere (eye ann. uh safer) is not a distinct layer of the atmosphere. Rather, it is a region of charged particles, or ions, that overlaps the lower troposphere.In the ionosphere, molecules of nitrogen and oxygen lose one or more electrons as they absorb high-energy wavelengths of solar radiation. The molecules become positively charged ions. These ions are most dense between the altitudes of 80 and 400 kilometers. At these high altitudes, certain piano tuner waves sent from Earths surface, such as AM piano tuner waves, bounce off ions and travel back to Earth. You can often hear AM radio stations from very far away at night because the suns radiation is blocked by Earth. The ions start o recombine at night, allowing AM radio waves to travel farther.