Thermal Energy Transfer in the Atmosphere Thermal Energy Transfer

What is Thermal Energy Transfer? There are three types of thermal energy transfer: Radiation Conduction Convection

Radiation Heat transfer by radiation is the transfer of heat through electromagnetic waves. http://www.nmsu.edu/~safety/images/fire_meaney.gif

Radiation There is no direct contact between the substances.

Radiant Energy from the sun radiates through empty space to earth. http://stardate.org/images/gallery/sun5.jpg http://www.blog.thesietch.org/wp-content/uploads/2007/04/earth.jpg

Radiant Energy from the sun consists of : Visible Light Ultraviolet Light- has a shorter wavelength than visible light and can cause sunburn and skin cancer Infrared Radiation- has longer wave length than visible light and is felt as heat

ENERGY ON EARTH Not all of the sun’s energy reaches the Earth’s Surface. 20% of the Sun’s Energy is ABSORBED by gases and particles in the Atmosphere. Ozone, Oxygen & Water Vapor absorb ultraviolet light Water and carbon dioxide(CO2) absorb infrared light. Earth’s Atmosphere (clouds) and the surface of the Earth REFLECTS about 30% of Sun’s radiation About 50% of the Sun’s radiation is absorbed by the Earth's Surface

RADIATION BALANCE Earth’s temperature remains stable because of the balance between the amount of radiation coming from the Sun and the amount going out from Earth. Land, trees, and the oceans absorb and emit solar radiation mainly in the form of infrared radiation.

THE GREENHOUSE EFFECT Glass allows sunlight into a green house. It prevents infrared radiation from escaping which keeps the greenhouse warm

THE GREENHOUSE EFFECT Certain gases, such as CO2, in the atmosphere act like the glass in a greenhouse warming the atmosphere.

What is Thermal Energy Transfer? Thermal energy transfer is the movement of heat energy from one substance to another. Heat (energy) always moves from objects with high temperature to objects with low Cold Hot

What is Thermal Energy Transfer? Heat will continue to move until both substances are the same temperature. Warm Warm

What is Thermal Energy Transfer? The greater the difference in temperature between the substances, the faster the heat will transfer.

Your Coke becomes cold because the heat from the soda http://www.photoanswers.co.uk/ImgGalleryTn/91/10191/2417_16333.jpg Your Coke becomes cold because the heat from the soda transfers into the ice, not the other way around.

No matter what it feels like, cold does not transfer into your body. What is really happening here? Why do you wear heavy clothes when it’s cold outside? http://www.alaska-in-pictures.com/data/media/9/man-in-extreme-cold_355.jpg

Examples Anti-Examples You touch a black car in the summer and the heat from the car transfers into your hand. A breeze makes you feel cooler because the wind transfers heat away from your body. You feel the cold of a winter day because the cold air transfers into you. Your Coke in a cooler gets cold because the cold from the ice moves into the Coke.

Conduction The transfer of thermal energy by the collisions between particles of matter. (through direct contact). Molecules transfer energy to the molecules next to them.

Conduction The molecules do not have to be the same substance. http://www.theelusivefish.com/articles/wp-content/uploads/2007/09/hot-stove.jpg

Conduction Thermal energy is CONDUCTED from the warm ground to the air above it.

cooler air, forming a convection current. As air above the road warms up, it becomes less dense and rises and is replaced by cooler air, forming a convection current. http://physics.uoregon.edu/~jimbrau/BrauImNew/Chap07/FG07_03.jpg

Convection Heat transfer by convection is the transfer of thermal energy (heat) through the fluid (liquids and gases) movement of currents.

Convection Warm fluids rise, cool down, sink, and then are warmed again.

The radiator warms the room by warming the http://www.eeb.ucla.edu/test/faculty/nezlin/Lecture1/Fig0803.jpg The radiator warms the room by warming the air around it. Then the warm air transfers heat to the rest of the room through convection.

When water changes from one phase to another, Latent heat is exchanged.

This picture illustrates all three type of heat transfer. http://www.aos.wisc.edu/~aalopez/aos101/wk5/heatrans.jpg This picture illustrates all three type of heat transfer. Can you identify them all?

Conduction Convection Radiation http://www.aos.wisc.edu/~aalopez/aos101/wk5/heatrans.jpg