UNIT 3 Heat transfer through earth’s subsystems
UNIT 3…..What’s it all about? • The source of ALL heat for our planet is found through the SUN. Therefore, when the sun warms our planet, the heat is transferred in 3 different ways through our atmospheres. These processes are: • RADIATION • CONVECTION • CONDUCTION We will also be taking a look at OCEAN CIRCULATION, which is another very important process that deals with the transfers of heat in our subsystems. With that all being said, LET’S GET STARTED!
Radiation • The transfer of energy (heat) through space by electromagnetic waves • EXAMPLE)- On sunny days, your body can feel the sunlight, even though the air around you may not be so warm. This energy that • your skin absorbs is an example of radiation. • Visible light is one example of electromagnetic waves. Our brain takes these frequencies and interprets it as color.(infrared, ultraviolet, etc.)
Convection • The transfer of heat by the movement of a mass or substance. • Because convection happens through liquids and gases, this helps to create warm and cold currents in the Earth’s atmosphere. The earth's surface and the air near the surface heats unevenly. The warmest air becomes less dense and becomes buoyant and begins to rise. These rising "bubbles" of warm air, called thermals, send the heat up into the atmosphere. Replacing the warm air, cooler and more dense air fills it’s place. This cycle continues and ends up creating clouds in the sky.
Conduction • The transfer of heat through matter by molecular activity. Energy is transferred through collisions from one molecule to another EXAMPLE)- when you hold a pan over fire and after a while, you hand begins to feel that same heat through the handle. The rate of heat transfer depends on your conductor. If you have a poor conductor of heat, your not going to gain as much energy as you would with a good conductor of heat.
Ocean circulation • Water current flow in a closed circular pattern within an ocean. Large-scale horizontal water motion within an ocean. Energy is not equally displaced over the Earth’s surface. In fact, most of it’s energy can be found at the equator. This creates drastic differences between the temperature of the equator and the poles. Because the ocean is immersed in all parts of the Earth, ocean circulation acts as a “cooling and heating” system for our diverse environments.
K.S • So….based off what we just learned, what is the main difference between convection and conduction?
Websites for research • http://www.atmos.illinois.edu/earths_atmosphere/heat_transfer.html • http://www.atmosphere.mpg.de/enid/