1. 47. How does atmospheric pressure at the bottom of a deep well compare to normal atmospheric pressure? Defend your answer.
2. 49. Why is a soft, underinflated football at sea level much firmer when it is at a high elevation in the mountains?
3. 51. How does the air density in a deep mine compare with the air density at Earth's surface? Why is this so?
4. 52. When an air bubble rises in water, what happens to its mass, volume, and density?
5. 61. Would it be slightly more difficult to drink soda through a straw at sea level or on top of a very high mountain? Or the same? Defend your answer.
6. 65. When you replace helium in a balloon with less-dense hydrogen, does the buoyant force on the balloon change if the balloon remains the same size? Explain.
7. 67. What change in pressure occurs in a party balloon that is squeezed to one-third its volume with no change in temperature?
8. 69. What happens to the speed of water ejected from a hose when you squeeze the opening and make it smaller?
9. 73. When a steadily flowing gas flows from a larger-diameter pipe to a smaller-diameter pipe, what happens to (a) its speed, (b) its pressure, and (c) the spacing between its streamlines?
10. 39. Rank the magnitudes of these units of thermal energy from greatest to least.
    1. a. 1 calorie
    2. b. 1 Calorie
    3. c. 1 joule
11. 45. Which is greater: an increase in temperature of 1 Celsius degree or an increase of 1 Fahrenheit degree?
12. 48. In a glass of water at room temperature, do .all the molecules have the same speed? Explain why, or why not.
13. 50. Which has the greater amount of internal energy: an iceberg or a cup of hot coffee? Defend your answer.
14. 54. Adding the same amount of heat to two different objects of the same mass does not necessarily produce the same increase in temperature. Why not?
15. 59. A certain quantity of heat is supplied to both a kilogram of water and to a kilogram of iron. Which undergoes the greater change in temperature? Defend your answer.
16. 61. When a 1-kg metal pan containing 1 kg of cold water is removed from the refrigerator and set on a table, which absorbs more heat from the room: the pan or the water? Why?
17. 67. Desert sand is very hot in the day and very cool at night. What does this indicate about its specific heat capacity?
18. 74. In terms of thermal expansion, why is it important that a key and its lock be made of the same or similar materials?
19. 87. A canister contains a mixture of hydrogen and oxygen gases at the same temperature. Which molecules move faster, and, why?
20. 40. If you touch the metal sides inside of a hot oven with your bare hand, you're in trouble. But hold your hand briefly in the oven air and you're okay. What does this tell you about the relative conductivities of metal and air?
21. 44. Wrap a fur coat around a thermometer. Will the temperature rise?
22. 54. Can heat spontaneously flow from an object with less internal energy to one with greater internal energy? Defend your answer.
23. 55. Why is it incorrect to say that when a hot object warms a cold object, temperature flows between them?
24. 61. While drinking iced tea, a friend remarks that cooling would be less if ice cubes were instead on the bottom of the drink. Do you agree or disagree? Explain.
25. 63. Air density is normally less above any point in air than below. In what sense does this provide an upward "migration window" in air? How does this affect the convection of faster-moving molecules in air?
26. 67. To save energy, some ceiling fans are reversible so that they drive air down or pull it up. In which direction should the fan drive the air during winter? In which direction for summer?
27. 74. Even though metal is a good conductor, frost can be seen on parked cars in the early morning even when the air temperature is above freezing. Provide an explanation.
28. 78. On a very cold sunny day, you wear a black coat and a transparent raincoat. Which coat should be worn on the outside for maximum warmth?
29. 80. Why is the insulation in an attic commonly thicker than the insulation in the walls of a house?
30. 43. From greatest to least, rank the energy needed for these phase changes for equal amounts of water.
    1. a. From ice to ice-water.
    2. b. From ice-water to boiling water.
    3. c. From boiling water to steam.
31. 45. Why is sweating an efficient mechanism for cooling off on a hot day?
32. 53. Double-pane windows have nitrogen gas or very dry air between the panes. Why is ordinary air a poor idea?
33. 61. A great amount of water vapor changes phase to become water in the clouds that form a thunderstorm. Does this release thermal energy or absorb it?
34. 62. Why does the temperature of boiling water remain the same as long as the heating and boiling continue?
35. 68. How can water be brought to a boil without heating it?
36. 77. What is the temperature of an ice-water mixture?
37. 78. Why is very cold ice "sticky" when touched with your hands?
38. 87. When ice in a pond melts, what effect does this have on the temperature of the nearby air?
39. 90. Suppose your refrigerator/freezer temperature stays at exactly 0C. If you place a glass of water into this appliance, would it freeze? If you placed an ice cube into this appliance, would it melt? Explain.
40. 51. If a pendulum is shortened, does its frequency increase or decrease? What about its period? How do frequency and period relate?
41. 55. When the frequency of a wave decreases, what happens to the period? The wavelength? Use equations in your explanation.
42. 60. What kind of motion should you impart to a stretched Slinky to provide a transverse wave? To provide a longitudinal wave?
43. 62. Red light has a longer wavelength than violet light. Which has the greater frequency? Which has greater energy for the same intensity?
44. 68. How many nodes, not including the endpoints, are there in a standing wave that is two wavelengths long? Three wavelengths long?
45. 72. Why is there a Doppler effect when the source of sound is stationary and the listener is in motion? In which direction should the listener move to hear a higher frequency? A lower frequency?
46. 75. How does the Doppler effect aid police in detecting speeding motorists?
47. 84. Why is lightning seen before thunder is heard?
48. 93. Astronomers find that light emitted by a particular element at one edge of a distant star has a slightly higher frequency than light from that element at the opposite edge. What do these measurements tell us about the star's motion?
49. 45. A friend said the temperature inside an oven is 500 and the temperature inside a particular star is 50,000. You're unsure whether your friend meant Celsius degrees or kelvins. How much difference does it make in each case?
50. 47. When heat flows from a warm object in contact with a cool object, do both objects undergo the same amount of temperature change? Explain.
51. 51. What happens to the gas pressure within a sealed gallon can when it is heated? When it is cooled? Why?
52. 52. Suppose you do 100 J of work in compressing a gas. If 80 J of heat escapes in the process, what is the change in internal energy of the gas?
53. 61. Would you cool a room if you plugged in an air conditioner unit and placed it on a table in the middle of the room? Defend your answer.
54. 64. A refrigerator moves heat from cold to warm. Why does this not violate the second law of thermodynamics?
55. 66. In buildings that are being electrically heated, is it at all wasteful to turn all the lights on? Is turning all the lights on wasteful if the building is being cooled by air-conditioning?
56. 69. According to the second law of thermodynamics, is the universe moving to a more ordered state or to a more disordered state?
57. 75.As a chicken develops from an egg, it becomes more ordered with time. Does this violate the principle of entropy? Explain.