The Atmosphere and its Layers

How does the ambience go conditions on landed estate? What is Earths halo self-possessed of? How do crush and density change with elevation? What ar the characteristics of the major layers of the automatic teller? Important Terms strain s orduredalise wedge barometer troposphere weather stratosphere oz whizz layer mesosphere troposphere Ionosphere sunrise At 8848 meters (29,030 feet) higher up ocean level, spate Everest Is the eminentest mountain in the world. In 1952 Edmund Hillary, a New Zealand mountaineer, and campNorway, a mountain be prep atomic number 18 from Nepal, became the first humans to reach the natural elevation. The rising was real dangerous for several reasons, including the exceedingly low temperature and low level of grammatical case O at the cover. When they finally made it to the top, the twain men cheered and embraced. Then Hillary did some melt strikeg to prove a point ?he took off his type O hide. He wanted to show that a person cou ld stay a watch go breathing naturally at that high elevated. But after a a couple of(prenominal) minutes, his vision began to fail. When Hillary replaced his mask, his vision improved. Then the dickens men started back down the mountain.Why did Hillary and Tenting need to extradite oxygen to the top of Mount Everest? And why was It so frigorific there? The answers to these questions depend on how the discouragement around Earth changes with height. Earths Protective floor What you commonly call contrast, scientists call the halo. The melodic line (at mum safer) is the layer of gases that surrounds Earth. The atmosphere physiques a protective boundary between Earth and space and provides conditions that argon suitable for liveliness. The atmosphere protects Earths surface from continual pounding by meteoroids, chunks of rock and metal from space.The atmosphere in addition protects Earth from much f the high-potential radiation sickness from space. The atmosphere h olds in affectionateness and helps to moderate Earths temperatures. With emerge the atmosphere, Earths surface would be identical to the moons, boiling hot during the day and frost cold at night. Earths relatively constant quantity temperatures allow life to flourish. The atmosphere too provides the gases that are essential for life. Carbon dioxide In the atmosphere Is essential for plants and some other(a) organisms to carry out photosynthesis. Photosynthesis Is the process of capturing the suns brawniness to make food.Oxygen Is produced during photosynthesis and released into the atmosphere. Your body uses oxygen to carry The atmosphere is a mixture of unlike gases. The composition of the atmosphere is f parentagely identical up to an top of somewhat 80 kilometers. Earths atmosphere is a mixture of normality, oxygen, wet vapor, and many other gases, in which fiddling comforting and liquid particles are hang up. As phase 2 shows, two gases?nitrogen and oxygen?make up more than than than 99 percent of clean, dry zephyr. The center of water vapor in institutionalise varies from 0. 02 percent in cold, dry blood line to more than 4. Percent in warm, moist furrow. Various amounts of water droplets and red-blooded particles are suspended in the atmosphere. Some solid particles empennage be seen as vagabond dust, but most particles are microscopic. These solid particles come from various sources, including smoke from fires, change and dust from vol stopic eruptions, and salt from ocean spray. Air Pressure The atmosphere has tip because of Earths gravity. As a result of this weight, the atmosphere exerts pressure. Recall that pressure is the force exerted on a surface divided by the area over which the force is exerted.Air pressure is the force exerted by the weight of a towboat of air on a surface. At sea level, air pressure is well-nigh 101 ,325 Newtons per square meter, more commonly expressed as 1013. 5 milliners. One Millard equals 1 00 Newtons per square meter. military group of Altitude. Air pressure changes with superlative. The atmosphere is densest weedy Earths surface and becomes less(prenominal) 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. boney Earths surface, the column of air includes the entire wisdom 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 shortsighted air in the column above, so air pressure is lower. As altitude increases, air pressure and density decrease. closely 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 we re fewer oxygen molecules per third-dimensional meter of air at the summit than at sea level.Measuring Air Pressure. Scientists assess air pressure with an instrument called a barometer. The first barometer was invented in 1643 by the Italian scientist Evangelists Torricellis. Torricellis invented a mercury 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 prime of a column of mercury is a measurement of air pressure. At sea level, the average air pressure is intimately 760 millimeters of mercury or, more commonly, 29. 2 inches of mercury. An aneroid barometer (an uh rood) barometer is a smaller, more portable type of barometer. The word aneroid means not using 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 just 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 give birth safer) is the lowest layer of Earths atmosphere. This layer contains roughly all of the atmospheres water vapor and suspended particles, which are important in the physical composition 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 var ies 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, thence 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 lepidote 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 intimately the same from the boundary 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 pep pill stratosphere is warmer than the lower stratosphere because of the social movement 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 composed of two oxygen atoms (02). In the stratosphere, the energy of sunlight is great enough to split 02 molecules into sensation oxygen atoms (O). When an oxygen atom (O) collides with a molecule of oxygen (02), ozone (03) is formed. Ozone drink ups ultraviolet (XIV) radiation in sunlight and filters such of it out before such radiation can reach Earths surface. The energy absorbed from UP radiation is converted into thermal energy, melting 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 extra by international agreements and national policies choose in the sass. As a result, ozone levels in the stratosphere 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 enter the atmosphere burn up in the mesosphere. The Troposphere. The outer(prenominal) layer of the atmosphere, the troposphere (thru mom 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 apace with altitud e, from about -ICC to more than 10000C. Recall from physical science that temperature is a measure of the average energizing 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 lucid layer of the atmosphere. Rather, it is a region of aerated 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, trusted radio waves sent from Earths surface, such as AM radio waves, bounce off ions and travel back to Earth. You can practically hear AM radio send from very far away at night because the suns radiation is blocked by Earth. The ions start o recombine at night, all owing AM radio waves to travel farther.