| A | B |
|---|
| Why are R-values for ceilings higher than those for walls in colder climates? | Because warm air rises, more heat transfer takes place through ceilings than through walls. |
| Why do liquids and gases transfer heat by convection and not conduction? | Because the energetic molecules of gases and liquids are free to move, they transfer little energy from molecule to molecule. Instead, energetic molecules are buoyed toward areas with less heat. |
| Which insulation is a better buy: one with an R-value of 88 and cost of $1 per square meter or one with an R-value of 44 and a cost of $.75 per square meter? | You get more insulation per dollar with the R-value of 88 insulation. |
| Which room heated by a forced-air furnace would probably feel warmer: one with warm air vents on the floor or one with warm air vents one foot from the ceiling? why? | Because warm air rises, vents on the floor would make a room feel warmer. |
| Why should you open a refrigerator as seldom as possible? | Warm air from the room replaces the cool air ini the refrigerator, causing the refrigerator to work harder. |
| How does room temperature affect the operation of a refrigerator? | The higher the room temperature, the harder the refrigerator must work. |
| Why are wooden handles used on cooking pots? | Wood is a thermal insulator. |
| Why must an air coniditoning system have one part outside? | The heat from the compressor must be allowed to vent outside or the heat will stay in the place that the air conditioner is trying to cool. |
| How does the world economy, organizations, and political crises affect the price of oil? | When the world economy slows does, oil prices fall. When prices are low, the economies begin to flourish. Fighting in the Middle East causes interruption of oil supplies. |
| condensation | A chnage from gas to liquid. |
| heat | Energy that flows from something hotter to something colder. |
| convection | Sets up currents. |
| insulator | Slows the flow of heat. |
| radiation | Transfers heat through space. |
| conduction | Occurs when atoms vibrate and pass along energy while in the same position. |
| evaporation | Chnaing from liquid to gas-used in cooling. |
| convection | transfer of heat from one place to another by wind. |
| specific heat | The amoung of heat it takes to raise the temperature of a substance one degree kelvin. |
| conduction | Transfers heat in metals. |
| A hot water heater heats by? | convection |
| Sunbathing is an example of what type of heating? | radiation |
| Placing your foot on a tile floor transfers heat by? | conduction |
| Goose down is a thermal? | insulator |
| Metals are thermal? | conductors |
| What do R-values do? | help determine evaporation rates. |
| How does a heat pump work? | Through radiant heating. |
| How does active solar heating work? | without any moving parts. |
| Why is the high specific heat of water valuable? | Because water can absorb and retain a lot of energy while increasing its temperatures only slightly, it can be used to transfer heat hrough a system. |
| Explain why compression of a fluid produces heat? | Compression pushed molecules closer together; as a c onsequence, they lose energy and give it off as heat. |
| Why does an air conditioner use a capillary tube? | The capillary tube allows the refrigerant to expand and absorb energy from the surroundings. |
| Why does evaporative cooling not work when the humidity is high? | Water does not evaporate as quickly because the air is near the saturation point. |
| Why is the word "radiator" in reference to radiator heating systems really the wrong word to use to describe what a radiator does? | The word "radiator" implies radiation, but a radiator heating system mostly works through conduction and convection. |
