Chapter 6 Notes Using Thermal Energy Thermal Energy

Chapter 6 Notes Using Thermal Energy

Thermal Energy on the “Moo”ve • Conduction- transfer of energy by direct contact of particles • Convection- transfer of energy by bulk movement of particles • Radiation- transfer of energy through waves.

Insulators • Good insulators do not allow heat to move easily through them. – Wood, plastic, glass, fiberglass, and gases such as air are excellent insulators. • Several insulating materials contain many tiny pockets of trapped air – Examples: » Styrofoam cups, down winter coats, fiberglass insulation.

Fluid • Fluid- anything that flows. • Yes, gasses are fluids too. • Solids are not fluids because they cannot flow.

Conventional Heating Systems • Radiator system: – Radiator- a device with a large surface area designed to heat the air near it by conduction. – Forced-air system- energy released in furnace heats the air. A blower is used. (pg. 163) – Electrical heating system- heating coils located within floors and ceilings are heated by electrical energy.

Solar Heating • Solar energy- energy from the sun. -It’s FREE!! 2 Types of Solar Heating Systems: 1. Passive Solar Heating- uses no fans or mechanical devices to transfer heat from one are to another. 2. Active Solar Heating- radiant energy is used to heat water that is then pumped throughout a house.

Using Heat to do Work • Heat engines – devices that convert thermal energy into mechanical energy. • Combustion – rapid burning of fuel. – Internal combustion engine – fuel burns inside the engine in chambers called cylinders. • Cars, trucks, etc. – External combustion engine – fuel is burned outside the engine. • Early locomotives

Heat Movers • Heat always flows from warmer to cooler areas. • Heat mover – a device that removes thermal energy from one location and transfers it to another location at a different temperature. – Example = refrigerators

Evaporation and Condensation • Evaporation is a cooling process. – When a liquid changes to a gas, energy is absorbed from the liquid’s surroundings. • What this means is that when you sweat, energy is released to the air around you, thus making you cooler. • Condensation is a warming process. – On humid days more water vapor is in the air around you. You sweat doesn’t evaporate as quickly, thus you don’t cool off as easily. • This is why you feel hotter on humid days.