#2 #6 #28 #34 #36 #44 #48 #52 #54 #582. What happens to the sound energy from your stereo speakers?
The ordered energy of the sound waves dissipates into the air, walls, etc. as randomized kinetic energy of molecules. This randomized molecular kinetic energy is heat.
6. How is a calorie defined?
It is the amount of energy needed to raise one gram of water one degree Celsius (or Centigrade).
28. Why does the coldest part of winter occur during late January and February when the shortest day is near December 21st?
It takes a long time for the heat in the ground to be transferred to the atmosphere.
34. Why is steam at 100 degrees C more dangerous than water at 100 degrees C?
Each gram of steam at 100 degrees C contains about 540 more calories of energy than each gram of water at 100 degrees C.
36. On nights when freezing temperatures are expected, some fruit growers turn on sprinkler systems in their orchards. Why?
Water's latent heat of melting is relatively high, and as the water freezes it loses a lot of heat energy (about 80 calories per gram of water), thus protecting the fruit.
44. Why might a cook put large aluminum nails in potatoes before baking them?
The aluminum nails are better conductors of heat than the potatoes. So, the aluminum nails conduct thermal energy to the interior of the potatoes helping them to cook faster.
48. A metal spoon is placed in one of two identical cups of hot coffee. Which cup will be hotter after a few minutes?
The cup of coffee without the spoon will remain hotter longer. In the cup with the spoon, heat is easily conducted through the spoon and subsequently lost to the outside air.
52. Will a Thermos bottle keep something cold as well as it keeps it hot?
The vacuum between the inner and outer parts of the Thermos is a thermal insulator. The vacuum simply does not allow heat to readily flow from or to the inner bottle. Thus, a Thermos bottle "keeps hot things hot and cold things cold."
54. Why are telephone lines higher in winter than in summer?
The telephone lines expand as outside temperatures rise, so the lines are longer in the summer than in the winter, while the poles stay about the same distance apart.
58. When a mercury thermometer is first put into hot water, the level of the mercury drops slightly before it begins to rise. Why?
The glass gets hot and expands first, so there is a larger volume for the mercury within the thermometer. This causes the mercury level to drop. Then the mercury also gets hot and expands so the mercury level within the thermometer rises.