Energy Transfer in the Atmosphere

Transcription

1 Energy Transfer in the Atmosphere Energy Transfer in the Atmosphere The sun provides most of the Earth s energy. This energy is what drives winds and ocean currents and allows Earth s plants to grow and produce food, which can then be eaten by many animals. There are three ways that the suns energy can be received by the earth. Some energy is reflected back into space by clouds, particles, and Earth s surface. Some is absorbed by the atmosphere or by land and water on Earth s surface.

2 Energy Transfer in the Atmosphere Heat Heat is energy that flows from an object with higher temperature to an object with a lower temperature. When the suns energy heats the Earth the heat is then transferred through the atmosphere through three ways radiaon, conducon, and convecon. Radiation When you are standing outside you can feel the suns warmth on your face. You feel this because energy from the sun reaches the earth in the form of radiant energy or radiaon. Radiaon is energy that is transferred in the form of rays or waves. Earth radiates some of the energy it absorbs from the sun back toward space. Radiant energy from the sun warms your face.

3 Energy Transfer in the Atmosphere Conduction If you walk on a hot beach your feet will get hot because of conducon. Conducon is the transfer of energy that occurs when molecules bump into one another. Molecules in warmer objects move faster than those in cooler objects. When objects are in contact energy is transferred from warmer objects to cooler objects. Radiaon from the sun heats the beach sand. Direct contact by your feet with the sand is what warmed your feet. Earths surface conducts energy directly into the atmosphere. As air moves over warm land or water, molecules in air are heated by direct contact. Convection Aer atmosphere is warmed by radiaon or conducon the heat is transferred by convecon. Convecon is the transfer of hear by the flow of material. Convecon circulates heat throughout the atmosphere. When air is warmed the molecules in it move apart and the air becomes less dense. Air pressure decreases because fewer parcles are in the same space. In colder air the molecules will move closer together and the air will become more dense increasing air pressure. Cooler more dense air will sink while warmer less dense air rises which forms a convecon current.

4 Energy Transfer in the Atmosphere The Water Cycle Hydrosphere is a term that describes all the waters of Earth. The constant cycling of water within the atmosphere and the hydrosphere plays an important role in determining weather paerns and climate types. Energy from the sun causes water to change from liquid to a gas by a process called evaporaon. Water that evaporates from lakes, streams, and oceans enters the Earths atmosphere. The Water Cycle If the water that enters the atmosphere cools enough it will change back into a liquid. This process of water vapor changing to a liquid is called condensaon. Clouds form when condensaon occurs high in the atmosphere. Clouds are made up of ny water droplets that can collide to form larger drops. As the drops grow, they fall to the Earth as precipitaon. This completes the water cycle within the hydrosphere.

5 Energy Transfer in the Atmosphere Earth's Atmosphere is Unique Radiaon from the sun can be reflected into space, absorbed by the atmosphere, or absorbed by land and water. Once it is absorbed heat can be transferred by radiaon. Why doesn t life exist on other planets like Mars or Venus? Mars is a cold, lifeless world because its atmosphere is too thin to support life or to hold much of the sun s heat.

6 Energy Transfer in the Atmosphere Earth's Atmosphere is Unique Gases on Venus dense atmosphere trap heat coming in from the sun making the surface of Venus as hot as 470 degrees C. Living things would burn instantly if they were placed on Venus surface. Life on Earth exists because the atmosphere holds just the right amount of the sun s energy.