6.2 Transferring Thermal Energy

Conduction Transfer of thermal energy (TE) by collisions between the particles in matter Transfer of thermal energy (TE) by collisions between the particles in matter Kinetic energy is transferred when faster moving particles bump into slower moving particles Kinetic energy is transferred when faster moving particles bump into slower moving particles This can happen in solids, liquids and gases, but since solid’s particles are closer together, solids are able to conduct heat better than liquids and gases This can happen in solids, liquids and gases, but since solid’s particles are closer together, solids are able to conduct heat better than liquids and gases

Convection Transfer of E by the movement of matter Transfer of E by the movement of matter Liquids and gases can flow, so their particles can move from one place to another, carrying E with them Liquids and gases can flow, so their particles can move from one place to another, carrying E with them When heating a liquid a convection current forms, rises, then cools and sinks When heating a liquid a convection current forms, rises, then cools and sinks

Radiation Transfer of E by electromagnetic waves Transfer of E by electromagnetic waves Does NOT require matter for heat transfer Does NOT require matter for heat transfer How the sun warms the Earth from 150 million Kilometers away! How the sun warms the Earth from 150 million Kilometers away! Called radiant E Called radiant E 34% reflects back into space 34% reflects back into space Only RE that is absorbed changes into thermal E Only RE that is absorbed changes into thermal E Different materials absorb RE differently: Shiny: reflects Different materials absorb RE differently: Shiny: reflects Dull: absorbs Dull: absorbs Dark colors absorb more than light colors Dark colors absorb more than light colors