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What is Energy? • Energy – the ability to do work • Everything that is done in the universe requires the use or transfer of energy. • Most of the surface processes on Earth are powered by energy from the Sun. Electromagnetic Radiation(Energy from the sun) Electromagnetic Radiation (Energy from the Sun) What do you think? A. Which item below describes infrared radiation? a. It is longer than visible light but shorter than radio waves. b. It is longer than radio waves but shorter than visible light. c. It has the same wavelength as gamma rays. d. None of the above B. Compare the wavelength of visible light to the wavelength of a microwave. a. Wavelength of visible light is shorter than a microwave. b. Wavelength of visible light is the same as a microwave. c. Wavelength of visible light is shorter than an x-ray. d. All of the above. What makes an object hot? • Heat: form of energy associated with the motion of atoms or molecules • Heat transfer – the movement of thermal energy due to a temperature difference(from a warmer object to a cooler object) • When an object is heated, the particles that make up the object move faster. • Heat transfer stops when both objects reach the same temperature. What do you think? C. Describe the heat flow from your hand at 20 degrees and a metal spoon at 19 degrees. a. Heat transfer will not occur. b. Heat from your hand will flow to the metal spoon increasing its temperature. c. Heat from the spoon will flow to your hand making it colder. d. Heat from your hand will flow to the metal spoon decreasing its temperature. Thermal Energy Transfer Thermal energy can be transferred by 3 processes: – Conduction – Convection – Radiation Types of Heat Transfer Radiation – the movement of electromagnetic radiation (energy) through space • No direct contact between heat source and an object • All objects radiate heat: hotter objects radiate more • The hotter the object, the shorter the wavelength • Radiation can be absorbed or reflected • Examples: --Heat felt from a campfire --radiation from the sun warms Earth --energy from the sun’s core heats outer surface of the sun What do you think? D. Which statement below is true? a. A glacier radiates energy. b. Earth radiates energy. c. Radiation from the sun will have a shorter wavelength than that of Earth’s wavelength. d. All of the above are true. Emission experiment Four containers were filled with warm water. Which container would have the warmest water after ten minutes? Dull metal Shiny metal Shiny black Dull black shiny metal container would be the warmest after ten The __________ minutes because its shiny surface reflects heat radiation _______ back dull black container into the container so less is lost. The ________ emitting heat would be the coolest because it is the best at _______ radiation. Absorption experiment Four containers were placed equal distances from a heater. Which container would have the warmest water after ten minutes? Dull metal Shiny metal Shiny black Dull black dull black container would be the warmest after ten The __________ radiation the best. minutes because its surface absorbs heat _______ shiny metal container would be the coolest because it is The _________ the poorest at __________ absorbing heat radiation. What do you think? E. In which container is the substance unable to transfer heat by convection? H J Types of Heat Transfer • Conduction – heat movement within an object or between objects that are touching. • Transfer of energy by touch • Not an effective transfer in a gas. • Primarily solids Conduction When you heat a metal strip at one end, the heat travels to the other end. As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on and so on, the vibrations are passed along the metal and so is the heat. We call this? Conduction Types of Heat Transfer • Convection– heat transfer by the movement(circulation) in fluids. • Caused by density • Hot fluid rises, cool fluid falls • Examples: – air in a heating system – Generates sea breezes, land breezes, and surface winds Fluids are liquids or gases. Water movement Cools at the surface Cooler water sinks Convection current Hot water rises Air Currents Why is it windy at the seaside? Sea Breeze Sea breeze: During a hot day, the land is warmer than the sea. Air above the land is heated and rises up; it is then replaced by cooler air from the sea • Occurs during the day • wind blowing from the ocean towards land Land Breeze Land breeze: During the night, the sea is warmer than the land because the land loses its heat much faster than the sea. Air above the sea is warmer than that above the land so it rises up to be replaced by that air above the land. • Occurs at night • blows from the land to the water Sea Breeze Land Breeze Heat cells in mantle/asthenosphere Rising heat cells - plates separate Sinking heat cells - plates pulled down into mantle Summary Summary Summary What do you think? F. The moon’s surface becomes hot during the long lunar day because the sun transfers heat to the moon. This heat transfer is accomplished almost entirely through the process of __________________________. What do you think? G. Why is radiation the only process that can transfer energy from the sun to the surface of Earth? What do you think? H. Which of the following is not a method of heat transfer? A. Conduction B. Insulation C. Radiation D. convection What do you think? I. How does heat energy reach the Earth from the Sun? a. Conduction b. Insulation c. Radiation d. convection What do you think? J. Solar Radiation and Earth Effect Amount of Energy per Second (terajoules) Solar radiation reaching Earth 173,410 Radiation reflected back into space 52,000 Radiation heating atmosphere, landmasses, and oceans 81,000 Radiation producing winds and ocean currents 370 Radiation used in photosynthesis 40 Radiation resulting in evaporation of water ? Assuming the chart contains all energy transformations in the Earth system, how much solar radiation goes toward evaporating water? F G H J 40,000 terajoules 92,410 terajoules 121,410 terajoules 133,410 terajoules What do you think? K. What percentage of incoming solar radiation is reflected by clouds? a. 5 % b. 20% c. 30% d. 50% L. Cloud coverage has increased to 90% today. Predict how incoming solar radiation may be impacted. a. More will be reflected back to space. b. More will be absorbed by the ground. c. More will be reflected or absorbed by the clouds. d. There will be no impact.