Presentation on theme: "Chapter 14.2 – Energy Transfer"— Presentation transcript:
1 Chapter 14.2 – Energy Transfer heat energy can be transferred three waysconductionconvectionradiationthermal conduction –the transfer of energy as heat through a materialtakes place between objects in direct contact aka touchingtakes place between particles within an object
2 Chapter 14.2 – Energy Transfer convection –energy transfer resulting from the movement of warm fluidsfluids are both liquids and gaseshot air rises, cold air sinkshot air is less dense, cold air is more denseconvection current –movement of matter that results from differences in densitymay be vertical, circular, or cyclicala heated fluid rises, cools, and then falls
3 Chapter 14.2 – Energy Transfer radiation –energy that is transferred as electromagnetic waveselectromagnetic waves –visible light, infrared radiation, ultraviolet rays, microwavesinfrared radiation –heat radiationradiation is the only way to transfer energy through a vacuumis how we get energy from the sun
4 Chapter 14.2 – Energy Transfer conductor –material through which energy can be easily transferred as heatinsulator –material that transfers energy poorlyconduction and convection transfer energy through particle collisionsthe less dense the material, the fewer the collisions, and the less energy transferredmetals conduct energy well, plastics conduct energy poorly
5 Chapter 14.2 – Energy Transfer specific heat –amount of energy required to raise the temperature of 1 kg or 1 g of a substance by 1 Kunits of J / kg * Kthe lower the specific heat, the easier it is to increase the temperature of a substancethe higher the specific heat, the harder it is to increase the temperature of a substance
6 Chapter 14.2 – Energy Transfer can find the energy needed to heat a substance a certain amount from:energy needed = specific heat x mass x temperature changeE = c m ΔTHow much energy is needed to increase the temperature of kg of iron from 283 K to 403 K?
7 Chapter 14.2 – Energy Transfer adding energy as heat to an object will either raise its temperature or change its stateit will not do both at the same time