Heat transfer in the Atmosphere The Sun provides most of the energy on Earth

The Sun, a major power source Drives winds Enhances ocean currents Allows plants to grow

When Earth receives energy from the Sun Some is reflected back into space -by clouds -by atmospheric particles -by the Earth’s surface Some is absorbed by the atmosphere Rest is absorbed by land and water on Earth.

Heat from the Sun Heat energy flows from an object with higher temperature To an object with lower temperature.

Heat from the Sun Reaches the Earth’s surface heats up objects such as roads, rocks, and water.

Heat from the Sun Transferred through the atmosphere in three ways: 1.) radiation 2.) conduction 3.) convection

Radiation Radiation is the transfer of heat energy by electromagnetic radiation. If you have stood in front of a fireplace or near a campfire, you have felt the heat transfer known as radiation. The side of you nearest the fire warms, while your other side remains unaffected by the heat. Although you are surrounded by air, the air has nothing to do with this transfer of heat. Heat lamps, that keep food warm, work in the same way.

Radiation Is how we get energy from the sun The energy is carried by electromagnetic waves The UV radiation is absorbed by the ozone Heats up the atmosphere IR (infrared) radiation is absorbed at the surface

Conduction Conduction is the transfer of heat energy from one substance to another or within a substance. Have you ever left a metal spoon in a pot of soup being heated on a stove? After a short time the handle of the spoon will become hot. This is due to transfer of heat energy from molecule to molecule, or atom to atom

Conduction Energy transfer when atoms or molecules bump into one another By direct contact Energy transfer continues until both substances are the same temp

Convection Is the transfer of heat in flowing currents in a liquid or gas most commonly seen in the kitchen when you see liquid boiling. Currents are caused by the difference in temperatures Hotter less dense molecules rise where they cool and condense and begin to sink

Convection in Air The sun's radiation strikes the ground, thus warming the rocks. As the rock's temperature rises due to conduction, heat energy is released into the atmosphere forming a bubble of air which is warmer than the surrounding air. (thermals)

Convection in air As it rises, the bubble cools with the heat contained in the bubble moving into the atmosphere. As the hot air mass rises, the air is replaced by the surrounding cooler, more dense air, what we feel as wind.

Convection in Air These movements of air masses can be small in a certain region such as local cumulus clouds, or large cycles in the troposphere, covering large sections of the earth. Convection currents are responsible for many weather patterns in the troposphere.

Convection in the air Successive thermals following the same path usually rise higher than previous ones if a thermal is able to rise high enough to cool to its saturation point , the moisture within condenses and becomes visible as a cloud.

Convection in the air if a deep unstable layer (cold air aloft) is present continued vertical growth is likely leading to the development of a cumulonimbus cloud, which contains raindrops

Radiation, Conduction and Convection (Demonstration)

Three ways to heat the atmosphere (or anything else, for that matter). These ways include conduction, convection, and radiation. Let’s use an analogy to help you figure this out.

There are three ways to cook popcorn. (conduction) 1.) Put oil in the bottom of a pan. Cover the bottom of the pan with popcorn kernels. Place the pan on the stove and turn on the burner to medium heat. Cover the pan with a lid. Periodically shake the pan so the kernels move around in the oil. Conduction is heat transfer through matter.

There are three ways to cook popcorn. (convection) 2.) Using a popcorn popper. Place the popcorn kernels in the popper. Plug in/turn on the popper. Hot air will transfer heat to the kernels, making them expand and pop. Convection is heat transfer by the movement of mass from one place to another. It can take place only in liquids and gases.

There are three ways to cook popcorn. (radiation) 3.) Microwave a bag of microwave popcorn. Radiation is the only way heat is transferred that can move through the relative emptiness of space. All other forms of heat transfer require motion of molecules like air or water to move heat.

There are three ways to cook popcorn. (Radiation) The majority of our energy arrives in the form of radiation from our Sun. Objects that are good absorbers of radiation are good radiators as well. When the Sun heats the Earth, the Earth gets warmer in that location and re-radiates heat into the atmosphere, making it doubly warm.

Three ways to cook popcorn (Radiation) This relates to popcorn example #3. The kernels are heated by the radiation in the microwave kernels heat up, giving off more heat to the kernels surrounding it and making it "doubly warm."

Heat transfer Name the three ways of heat transfer? Give a short definition of each one. Give an example of each one. Take one sheet of paper and answer these three questions. (Put name on paper) This will be your ticket out the door. (Enjoy your popcorn!)