Energy TransferSubtitle

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Objectives

•Review Earth System•Review the Water cycle•Go over heat transfer through conduction, convection, and radiation•Review Greenhouse Effect

July 22, 2012

What are the different systems of the Earth?•A system is a set of interacting parts/members that form an integrated whole•Think of the organ systems within your body and how they all have individual parts/organs but function as a whole

What are the different systems of the Earth?•Atmosphere – “atmos” means vapor/gas; the gaseous envelope surrounding the earth•Hydrosphere – “hydro” means water; all the water and the vapor in the atmosphere•Cryosphere – “cryos” means ice/freezing; the region of the earth’s surface that is frozen throughout the year

What are the different systems of the Earth?

•Geosphere - “geo” means earth; the solid earth

•Biosphere – “bio” means living; the area in which there are living organisms

How is water transferred through Earth’s systems?•The hydrologic (Water) cycle•Evaporation – liquid to gaseous state •Condensation – gaseous to liquid state•Melting – solid to liquid state•Freezing – liquid to solid state•Transpiration – evaporation from plants•Precipitation – from atmosphere back to geosphere/biosphere/hydrosphere

Transferred Thermal Energy

•Heat – is defined as energy transferred from one system to another when the systems are at different temperatures•“Hot” and “cold” are used to compare one object’s temperature to another or its surroundings•Ex: “It was really cold this morning” – no it wasn’t, the atmosphere was just a lower temperature than your body temperature

Why do some things feel hot, while others feel cold?

•When systems with different temperatures touch energy is transferred from the higher temperature system to the lower temperature system.

•Ex. Feet on a cold tile floor. Energy is drained from your feet to the tile floor making your feet feel colder.•Ex. Your hand on a warm metal pot handle. Energy is gained from the handle to your hand making it feel warmer.

Explain why a doctor’s stethoscope feel cold when it touches your back?

•Answer the question in your own words

Other Important Information

•Heat always moves from a warmer place to a cooler place

•Temperature is a measure of the average kinetic energy of the particles in an object

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Heat and Thermal Energy

July 22, 2012

• Thermal Energy – the total kinetic (moving) energy of the particles that make up a substance

• The amount of thermal energy an object has depends on two factors.• The temperature - When two substances

of equal mass have different temperatures, the substance with the higher temperature has more thermal energy

• The Mass - The greater the mass of a substance of a given temperature, the more thermal energy it has.

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Thermal Energy Transfer

Sketch and summarize the information in Figure 2.

July 22, 2012

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What will happen if two objects at different temperatures come into contact?•Answer question in your own words

•Other Important Information•Heat always moves from a warmer place to a cooler place•Specific Heat- the measure of the amount of energy required to increase the temperature 0f 1 g of substance by 1o C

July 22, 2012

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What three examples of heat transfer are given?

July 22, 2012

What are the three ways that thermal energy is transferred? Conduction•Conduction – transfer of energy through materials touching•All atoms are vibrating, which means they have kinetic energy. Hot atoms have more energy. When hot atoms bump into cold atoms, they transfer energy•Closer atoms mean more collisions•Conductor vs. Insulator

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Conductor vs. Insulator•Conductor-allows energy in the form of heat, to be transferred within the material, without any movement of the material itself

• Insulator- material that does not allow a transfer of electricity or energy. Materials that are poor thermal conductors can also be described as being good thermal insulators.

July 22, 2012

What are the three ways that thermal energy is transferred? Convection•Convection – transfers heat through moving currents in gases or liquids•Hot liquids and gases are less dense and rise. Cool liquids and gases are more dense and sink. These are convection currents.

What are the three ways that thermal energy is transferred?•Radiation – transfers heat through electromagnetic radiation; occurs even in a vacuum (empty space), doesn’t need to transfer through contact of atoms•All energy on earth comes originally from the sun. Space is a vacuum, so only radiation can travel through space to earth

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Convection Currents : a current in a fluid that results from

convection.

July 22, 2012

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Radiation and the Greenhouse Effect

July 22, 2012