# Chapter 14.2 – Energy Transfer

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Chapter 14.2 – Energy Transfer
heat energy can be transferred three ways conduction convection radiation thermal conduction – the transfer of energy as heat through a material takes place between objects in direct contact aka touching takes place between particles within an object

Chapter 14.2 – Energy Transfer
convection – energy transfer resulting from the movement of warm fluids fluids are both liquids and gases hot air rises, cold air sinks hot air is less dense, cold air is more dense convection current – movement of matter that results from differences in density may be vertical, circular, or cyclical a heated fluid rises, cools, and then falls

Chapter 14.2 – Energy Transfer
radiation – energy that is transferred as electromagnetic waves electromagnetic waves – visible light, infrared radiation, ultraviolet rays, microwaves infrared radiation – heat radiation radiation is the only way to transfer energy through a vacuum is how we get energy from the sun

Chapter 14.2 – Energy Transfer
conductor – material through which energy can be easily transferred as heat insulator – material that transfers energy poorly conduction and convection transfer energy through particle collisions the less dense the material, the fewer the collisions, and the less energy transferred metals conduct energy well, plastics conduct energy poorly

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 K units of J / kg * K the lower the specific heat, the easier it is to increase the temperature of a substance the higher the specific heat, the harder it is to increase the temperature of a substance

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 change E = c m ΔT How much energy is needed to increase the temperature of kg of iron from 283 K to 403 K?

Chapter 14.2 – Energy Transfer
adding energy as heat to an object will either raise its temperature or change its state it will not do both at the same time