ATMOSPHERE Shields us against ultra violet rays, bombardment of meteors, meteorites, and other objects from outer space. Gases in the atmosphere is essential to life. It supplies the oxygen and carbon dioxide needed by living things. As an insulator, it prevents extreme temperature.
LAYERS OF THE ATMOSPHERE 1. TROPOSPHERE 2. STRATOSPHERE 3. MESOSPHERE 4. THERMOSPHERE /IONOSPHERE 5. EXOSPHERE
TROPOSPHERE We live in the troposphere. It extends about 14 to 16 km from the earth’s surface. Air is densest. Most of the water vapor in the atmosphere is found in this layer. Clouds, weather and storm occur here. JET STREAM – the topmost part of the troposphere which has fast-moving river of air. It was discovered by WW II pilots. TROPOPAUSE – boundary between the troposphere and stratosphere
STRATOSPHERE It is about 50km above the earth. Very little water vapor is present in this layer. Air flows in horizontal direction. Pilots fly their aircraft here to take advantage of the horizontal wind and to void the weather in the troposphere. No clouds in this layer. OZONE LAYER ( O3) is found in the topmost part of the stratosphere making this layer warm; protects us against ulta violet rays.
MESOSPHERE Extends to about 90 km above the earth. In this layer temperature decreases with height. Coldest region of the atmosphere. Most meteors from space burn in this layer
THERMOSPHERE The topmost part of the atmosphere Temperature can go as high as 1 7270C In here, the sun’s radiation strips off some of the electrons from the gases present in this region making them electrically charged or ionized. This layer reflects long electromagnetic wave back to earth making radio communication possible. Aurora occurs (display of colors )- ions glow in diff. colors
EXOSPHERE Starts at the top of the thermosphere and continues until it merges with interplanetary gases or space. Hydrogen and helium are the prime components and are only present at extremely low densities.
ENERGY SOURCE OF THE ATMOSPHERE A significant aspect of the atmosphere is motion. HEAT - kinetic energy in a moving molecule. Heat travels from hotter substance to cooler substance. It is a measure of energy. TEMPERATURE – refers to the degree of hotness. SUN – major source of energy on earth.
METHODS OF HEAT TRANSFER 1. CONDUCTION – is the transfer of heat from one substance to another by direct contact.
2 CONVECTION - is heat transfer by mass motion of a fluid such as air or water when the heated fluidis caused to move away from the source of heat, carrying energy with it. Convection above a hotsurface occurs because hot air expands, becomes less dense, and rises (see Ideal Gas Law). Hotwater is likewise less dense than cold water and rises, causing convection currents which transportenergy.
3. RADIATION – heat energy travel in empty space. It travels in the form ofwaves given off by hot objects. This is the reason why a heavily lighted room iswarmer than a room with a single bulb.