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27 Cards in this Set
- Front
- Back
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Kinetic Energy |
Energy of movement Ek=1/2mv^2 |
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Potential Energy |
Stored energy due to position OR Potential to do work Ep=mgh |
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Temperature |
A measure of the average kinetic energy of an object |
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Thermal Equilibrium |
Objects touching reach the same temperature |
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Heat |
The transfer of energy from a hotter object to a cooler object until thermal equilibrium is reached |
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Conductors |
Materials that easily allow for heat to be transferred along them To be a good conductor atoms of an object able to readily increase vibrations to transfer kinetic energy along the object. Free electrons also assist eg. metals |
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Insulators |
Materials that do NOT conduct heat eg. glass, water, plastic |
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Internal Heat Thermal Energy |
Sum of kinetic and potential energy of all the particles of an object Ek+Ep |
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Celsius to Kelvin |
+273.15 |
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Assumptions of Kinetic Theory of Matter |
-everything is made of particles -forces exist between particles -all particles have motion (move or vibrate) -all collisions= no loss of energy |
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Evaporation |
1. Liquid accumulates (eg. sweat) 2. Under suitable conditions it evaporates 3. Evaporation is a change of phase thus requiring energy (latent heat) 4. Energy is taken from object/body causing a decrease in kinetic energy and thus temperature =cooler |
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Solid |
-fixed position -vibrates -regular shape ->difficult to change -close particles -attractive forces hold together -repulsive forces stop collapse |
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Liquid |
-moves -takes the shape of container -moves to lowest part of container -reasonably close particles -weaker forces |
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Gas |
-fills container -particles are far apart (low density) ->easily compressed - little forces holding together -> move freely |
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Conduction |
Transfer of heat energy through solid objects -only occurs in solids |
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Covection |
Mass movement of fluid from one place to another -only occurs in fluids (liquids & gases) |
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Radiation |
Energy transfer through electromagnetic waves
-doesn't require particles |
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Energy |
Quantity of energy Q=mc^T Quantity of heat required to produce a change of phase Q=mL Change of energy mc^T=mc^T |
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Latent Heat of Fusion |
Change from solid to liquid |
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Latent Heat of Vaporisation |
Change from liquid to gas |
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How Conduction Occurs |
1. External source of heat energy is applied to solid 2. Particles of solid are in a fixed position but are vibrating 3. Increase in heat energy means an increase in kinetic energy thus causing an increase in particle vibrations 4. This increase in vibrations is rapidly passed along particles thus causing an increase in kinetic energy =hotter eg. Heat travelling from the hot end to the cold of a poker with one end in the fire |
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How Convection Occurs |
1. particles heated causing an increase in kinetic energy 2. increased vibrations cause particles to move apart becoming less dense 3. lesser density allows particles to rise 4. cooler particles move to take their place and the process repeats 5. away from the heat source heated particles cool becoming more dense and sinking where they are then reheated =convection current eg. Heat from the fire burner of a hot air balloon transferring heat to the air and causing the air and thus the balloon to rise |
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How Radiation Occurs |
1. Electromagnetic wave from heat source is transferred without a medium, hitting an object 2. The energy of the wave causes the particles of the object to increase vibrations 3. Increase in vibration means increase in kinetic energy thus increase in temperature =hotter eg. Heat travelling from a fire through space in the form of infrared radiation |
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Physiological Methods of Keeping Warm |
1. Constricting blood vessels -limited effect
2. Shivering-> movement of muscles to generate internal heat -effective
3. Chemical-> increase metabolic rate (eg. adrenaline, thyroxin) |
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Behavioural Methods of Keeping Warm |
1. Clothing we wear 2. Shelter 3. Use of heaters 4. Moving |
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Physiological Methods of Keeping Cool |
1. Evaporation (perspiration) 2. Increase blood flow near surface of skin -limited effect |
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Behavioural Methods of Keeping Cool |
1. Loose, light clothing 2. Fans and air conditioners 3. Minimal movement 4. Shelter |
