Name: ________________________________ Weather & Climate Notes 7th Grade Science – Mrs. Stabler & Mrs. Raimo Date: __________________ Period: ________ Air 1. Although we cannot see air it has mass. 2. Because air has mass, it also has pressure. 3. What is air pressure? the pressure caused by the weight of a column of air pushing down on an area The Atmosphere 4. What is the atmosphere? the atmosphere is the outermost Earth System of gases and particles of matter 5. What are some reasons the atmosphere is essential to life on Earth? contains oxygen and carbon dioxide, and water necessary for life acts like insulation on a house to keep the Earth warm protects living organisms from some of the Sun’s harmful rays protects Earth’s surface from being hit by meteoroids 6. Each layer has unique properties including composition of gases, and how temperature changes with altitude. 7. What is altitude? height above sea level The Troposphere 8. What is the troposphere? the atmospheric layer closest to Earth’s surface 9. The troposphere extends from the face of Earth’s surface to altitudes between 8 - 15 km. 10. What happens to temperature as you move up higher in the troposphere? temperature decreases as you move away from the surface 11. This is the layer where most of Earth’s weather occurs. The Stratosphere 12. What is the stratosphere? the atmospheric layer directly above the troposphere 13. The stratosphere extends from about 15 km to about 50 km. 14. The stratosphere contains the ozone layer. What is the ozone layer? the area of the stratosphere with a high concentration of ozone 15. Due to the ozone layer, temperatures increase as altitude increases within the stratosphere. The Mesosphere and Thermosphere 16. The mesosphere extends from the stratosphere (50 km) to about 85 km. 17. The thermosphere can extend from the mesosphere to more than 500 km above Earth’s surface. 18. Compare the size of these layers to the troposphere and stratosphere. these layers are much broader than the troposphere and stratosphere, yet only 1% of the atmosphere’s gas molecules are found here 19. The ionosphere is a region within the mesosphere and thermosphere that contains ions. 20. Where is the ionosphere? (in terms of altitude) between 60 km and 500 km 21. What are auroras? and how are they created? stunning display of lights in the ionosphere, ions from the Sun strike air molecules, causing them to emit vivid colors of light The Exosphere 22. What is the exosphere? the atmospheric layer furthest from Earth’s surface 23. The exosphere extends from 500 km out to space. It has no definite end, the molecules here can escape Earth’s gravity and travel into space. 24. Pressure and density is so low here that individual gas molecules rarely strike each other. 25. What causes the molecules here to move at incredibly fast speeds? they absorb radiation from the Sun Energy in the Atmosphere 26. Energy in the form of heat is transferred throughout the atmosphere. 27. Type of Heat Transfer Definition Radiation Transfer of heat through space Conduction Transfer of heat through direct contact Convection Transfer of heat within a fluid/air 28. How is the troposphere mostly heated? through convection Weather Patterns Winds 29. What is wind? the horizontal movement of air from an area of high pressure to and area of low pressure 30. Winds are caused by differences in air pressure 31. How are winds described? by their direction and speed 32. Wind direction is determined with a wind vane. 33. Wind speed is measured with an anemometer. Local Winds 34. What are local winds? winds that blow over short distances 35. Local winds are caused by unequal heating of Earth’s surface within a small area. Global Winds 36. What are global winds? winds that blow steadily from specific directions over long distances 37. What causes global winds? unequal heating of Earth’s atmosphere 38. Warm air rises at the equator and cold air sinks at the poles, therefore air pressure tends to be lower near the equator and greater near the poles. The Coriolis Effect 39. What is the Coriolis Effect? the change that Earth’s rotation causes in the motion of objects and that explain how winds curve 40. Global winds in the Northern hemisphere gradually turn towards the right and in the Southern hemisphere winds cure to the left. Global Wind Belts 41. Wind Belt Definition Doldrums Near equator, little or no wind. Calm area where warm air rises Horse Latitudes Areas 30 degrees north and south of the equator; calm areas of falling air Trade Winds Blow from horse latitudes toward the equator; generally blow from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere Prevailing Westerlies Blow west to east and away from the horse latitudes; play an important role in the weather of the United States. Polar Easterlies Cold air near the poles sinks and flows back toward the lower latitudes; blow east to west; major effect on the weather in the U.S. Jet Streams Bands of high-speed winds about 10 kilometers above Earth's surface. Air Masses 42. Scientists classify air masses according to two characteristics: temperature and humidity. 43. Temperature affects air pressure. 44. Cold, dense air has higher pressure, while warm, less dense air has lower pressure. Type of Air Mass Description Tropical warm, forms in tropics, low air pressure Polar cold, forms at the poles, high air pressure Maritime humid, forms over oceans Continental dry, forms over land Type of Air Mass Description Maritime Tropical humid, warm air mass Maritime Polar humid, cold air mass Continental Tropical dry, warm air mass Continental Polar dry, cold air mass