Name __________________Date ______

Chapter 16: Heat Transfer

Exercises: Text page 321

2. If 70°F air feels warm and comfortable to us, why does 70°F water feel cool when we

swim in it?

4. If you hold one end of a metal nail against a piece of ice, the end in your hand soon

becomes cold.Does cold flow from the ice to your hand? EXPLAIN

7. Tongues have been injured by licking a piece of metal on a very cold day. Why would

no harmresult if a piece of wood were licked on the same day?

8. Wood is a better insulator than glass. Yet fiberglass is commonly used as an insulator

in woodenbuildings. EXPLAIN.

13. Why is it that you can safely hold your bare hand in a got pizza oven for a few seconds,

but if you momentarily touch the metalinside you will burn yourself?

15. Wood has a very low conductivity. Does it still have a low conductivity if it is very hot

(smoldering red hot coals)? Could you safely walk across a bed of red-hot wooden coals

with bare feet? Although the coals are hot, does much heat conduct from them to your feet

if you step quickly? Could you do the same on red-hot iron coals? EXPLAIN

25. In a mixture of hydrogen and oxygen gases at the same temperature, which molecules

move faster? Why?

34. Why does a good emitter of heat radiation appear black at room temperature?

38. Suppose at a restaurant you are served coffee before you are ready to drink it. In order that

it be hottest when you are ready for it, would you be wiser to add cream to it right away,

or when you are ready to drink it?

41. It’s commonly known that a white-painted house is a good idea in hot summer weather, because

more sunlight is reflected from the exterior, making for a cooler interior. But a white-painted house

is also a good idea in the cold winter. Why so?

47. If you wish to save fuel and you’re going to leave your warm house for a half hour or so on a very

cold day, should you turn your thermostat down a few degrees, turn it off altogether, or let it remain

at the room temperature you desire?

48. If you wish to save fuel and you’re going to leave your cool house for a half hour or so on a very

hot day, should you turn your air conditioning thermostat up a bit, turn it off altogether, or let it

remain at the room temperature you desire?