Heat Transfer & Phases Intro Chapter. Is the ability to do work and cause a change. Can be...
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Transcript of Heat Transfer & Phases Intro Chapter. Is the ability to do work and cause a change. Can be...
Heat Transfer& Phases
Heat Transfer& Phases
Intro Chapter Intro Chapter
• Is the ability to do work and cause a change.
• Can be transferred.– Gases and liquids are made of molecules that are
constantly moving (kinetic energy). The faster they are moving the more energy they have.
– Solids- molecules vibrate close together and transfer energy.
Energy
• The energy transferred from a hotter object to a cooler one.
• Three ways it is transferred.
Heat
• Is the total energy of motion in the molecules of a substance. • Gases are made of molecules that are
constantly moving. The faster they are moving the more energy they have.
Thermal Energy
• The average amount of energy of motion in the molecules of a substance.
• It is a measure of how hot or cold something is.
Temperature
Speed of Molecules & Temp
• What happens to the speed of the molecules when temperature is increased?
Speed of Molecules & Temp
• What happens to the speed of the molecules when temperature is increased?
Speed of Molecules & Temp
• What happens to the speed of the molecules when temperature is increased?
Speed of Molecules & Temp
• What happens to the speed of the molecules when temperature is increased?
Phase Changes
• When a substance changes from one state or phase to another.
• Solids
• Liquids
• Gases
• Always occur with a change in heat, which is energy.
Solids
• Have definite shape and volume
• Solid to liquid- melting
• Solid to gas- sublimation
Liquids
• Has a definite volume, and is able to take the shape of the container holding it.
• Liquid to solid- Freezing
• Liquid to gas- vaporization
• Boiling and Evaporation
Gases
• A state of matter without definite shape or volume.
• Phase Change-
• Gas to liquid- condensation.
Remaining Time:
Remaining Time:
Remaining Time:
Remaining Time:
Remaining Time:
Remaining Time:
• The direct transfer of energy over long distances of empty space.
• Moves in waves. (Electromagnetic Waves)
• Can not see it, but feel it a heat (Infrared)– Sunlight– Open fire
ClimateRadiation
• Heat transfer by direct contact of particles of matter. (Transfer by Touching)
• Particles bump into each other and transfer their energy heating them up.– Putting your hand on a hot
stove.
Conduction
• Heat transfer by the circular movement of a fluid (liquids and gasses).
• Particles flow transferring heat energy.• Caused by differences in density.
Convection
• Density: the amount of mass in a given volume. D=M/V
• Heated Fluids:– Move faster and bump into other particles.– They spread out increasing the volume.– Density decreases
• Cooling Fluids– Move slower– They come together decreasing the volume.– Density increases
How Convection Works