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Heat

Heat

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Heat

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  1. HEAT © MDR PUBLISHING 2011

  2. Is energy HEAT You cannot see it But you can see its effect on matter © MDR PUBLISHING 2011

  3. Heat makes matter change……. temperature state volume © MDR PUBLISHING 2011

  4. ALL MATTER is made of PARTICLES Liquids Solids Gases These particles are continually moving © MDR PUBLISHING 2011

  5. Temperature Is the amount of movement of particles High temperatures More movement Low temperatures Less movement © MDR PUBLISHING 2011

  6. There is a temperature When the particles STOP MOVING This is called ABSOLUTE ZERO - 273 o C © MDR PUBLISHING 2011

  7. Temperature is measured using a thermometer The bulb contains a liquid This heats up and expands into a capillary tube © MDR PUBLISHING 2011

  8. Celsius calibrated the thermometer USING WATER He defined 0oC as 100 the freezing point of water And 100oC as 0 the boiling point of water © MDR PUBLISHING 2011

  9. Temperatures can be changed in by…. Adding Heat, + Q Removing Heat, - Q © MDR PUBLISHING 2011

  10. Or by…. Doing work, W © MDR PUBLISHING 2011

  11. Thermal equilibrium Heat flows Until In a closed container Between objects They reach the same temperature 100oC 30oC 0oC 30oC

  12. Changing state: liquid to gas As particles in a liquid are heated They move faster Until eventually They start to escape Into the gas State This is called evaporation © MDR PUBLISHING 2011

  13. Changing state: solid to liquid Temperature measured Ice is heated and its The temperature increasesagain The heat is used to help particles Latent HEAT of FUSION Change state At first its temperature increases Until it starts to melt This energy is called When ALL the ice has melted © MDR PUBLISHING 2011

  14. Changing state: liquid to gas 100 oC As the water is heated…. its temperature increases…. until it starts to boil….. This happens at about 100 oC Energy is then used up To help particles escape From a liquid into the gas state This energy is called …. LATENT HEAT of EVAPORATION 0 oC © MDR PUBLISHING 2011

  15. Heat can move in three ways In solids In fluids In vacuum Conduction Convection Radiation © MDR PUBLISHING 2011

  16. Conduction Heat is carried by FREE ELECTRONS Metals are good heat conductors They have many free electrons © MDR PUBLISHING 2011

  17. Convection Air near the flame is heated and EXPANDS its density is less than the cold air around it And it rises © MDR PUBLISHING 2011

  18. Radiation Matter is made of particles These particles vibrate And emit radiation © MDR PUBLISHING 2011

  19. Everything that is warmer than absolute zero emits radiation EVERYTHING! © MDR PUBLISHING 2011

  20. The particles in my hand vibrate And emit radiation At 35oC the radiation isn’t visible But a thermal camera can see it At about 1000 oC the radiation Becomes visible A light bulb filament reaches Over 3000 oC ? © MDR PUBLISHING 2011

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