Q&A Hero

Q: Food in a pressure cooker is cooked faster due to A) higher temperature. B) greater rate of bubble formation in the water. C) energy transfer in the water. D) all of the above E) none of the above

Q: Morning dew on the grass is a result of A) evaporation of water. B) the open-structured form of water crystals. C) air pressure on water vapor. D) slow-moving water molecules sticking to one another.

Q: On a muggy day, water molecules in the air that strike our bodies A) transfer some of their kinetic energy to us. B) gain kinetic energy as they change phase. C) form an insulating layer on our bodies.

Q: We feel uncomfortably warm on a muggy day because water molecules are A) evaporating from our moist bodies. B) condensing on our bodies. C) evaporating and condensing on our bodies at the same rate. D) none of the above

Q: Steam burns are more damaging than burns caused by boiling water because steam A) has more energy per gram than boiling water. B) releases additional energy when it condenses. C) both of these D) neither of these

Q: A boy scout will be burned more severely by A) 100 g of water at 100C. B) 100 g of steam at 100C. C) both about equally D) neither of these

Q: Evaporation is a cooling process and condensation is A) a warming process. B) a cooling process also. C) neither of these

Q: When a geyser erupts, pressure at its bottom A) increases. B) decreases. C) is unaffected D) all of the above E) none of the above

Q: The pressure at the bottom of a geyser is A) less than nearer the top. B) the same as nearer the top C) greater than nearer the top. D) all of the above E) none of the above

Q: The main difference between a fog and a cloud is A) water vapor content. B) density of vapor. C) seeding. D) altitude. E) temperature.

Q: When slow-moving water molecules collide they tend to A) rebound without sticking. B) stick. C) both of these D) neither of these

Q: When fast-moving water molecules collide they tend to A) rebound without sticking. B) stick. C) both of these D) neither of these

Q: The toy drinking bird nicely illustrates A) evaporation. B) condensation. C) both of these D) neither of these

Q: Double-pane windows contain nitrogen rather than air to prevent A) gas escape. B) thermal conduction. C) condensation. D) heat flow.

Q: A canteen that is wet on the outside results in water inside that is A) warmer. B) cooler. C) both of these D) neither of these

Q: What occurs in a pan of water placed outdoors on a warm day? A) evaporation B) condensation C) both of these D) neither of these

Q: The surface of hot water has a relatively high rate of A) evaporation. B) condensation. C) conductivity. D) convection.

Q: A hot dog pants A) to enable evaporation in its mouth and bronchial tract. B) to provide more oxygen into its lungs. C) to impress dogs of the opposite sex. D) none of the above

Q: When you blow over hot soup to cool it you are helping A) to slightly increase air pressure atop the soup surface. B) more energetic particles in the soup to escape. C) conduction, convection, and radiation. D) none of the above

Q: The reason that evaporation is a cooling process is A) radiation of heat during the process. B) due to conduction and convection. C) the more energetic molecules escape the liquid. D) all of the above E) none of the above

Q: The molecules in a room-temperature glass of water jostle around at A) a great variety of speeds. B) much the same rates of speed. C) a very small range of speeds.

Q: Wrapping a hot potato in aluminum foil significantly reduces the rate at which it cools by A) conduction. B) condensation. C) evaporation. D) melting.

Q: Rapid evaporation of hot water can lead to A) superheated steam. B) the formation of ice. C) both of these D) neither of these

Q: The minimum amount of steam at 100oC needed to melt 1 gram of 0oC ice is A) 0.125 gram. B) 0.148 gram. C) 6.75 grams. D) 8 grams. E) none of the above

Q: The mass of ice that can be melted by 1 gram of 100oC steam is (Hint: Don't forget about hot water remaining from condensed steam.) A) 0.125 gram. B) 0.148 gram. C) 6.75 grams. D) 8 grams. E) none of the above

Q: Which involves a larger number of calories? A) the condensation of 1 gram of steam at 100oC to water at 100oC B) the cooling of 1 gram of water at 100 degrees Celsius to 1 gram of ice at absolute zero C) both the same D) none of these

Q: The calories needed to change 10 grams of ice at 0oC to steam at 100oC is A) 6200. B) 6400. C) 7200. D) 8000. E) none of the above

Q: Stored potatoes, beets, and rutabagas in an unheated well-insulated room can be protected from freezing by having in the room A) blocks of foam plastic. B) large tubs of water. C) an ample supply of fire wood. D) none of the above

Q: Stored potatoes, beets, and rutabagas freeze at temperatures below zero degrees Celsius (rather than at exactly zero) because A) they are good radiators of energy. B) they are good absorbers of radiant energy. C) the water in them contains dissolved salts and sugars. D) they are relatively dense. E) all of the above

Q: Firefighters find that the temperature of burning material is best lowered when water is A) used in small amounts. B) pointed away from the flames. C) sprayed as a fine mist. D) salted.

Q: A heat pump can A) cool an environment. B) warm an environment. C) both of these D) neither of these

Q: Which will melt more ice when placed on its surface, a kilogram of wood or a kilogram of iron of the same high temperature? A) 1 kg of wood. B) 1 kg of iron. C) both the same D) neither of these

Q: When water vapor changes phase to become water in a cloud, the surroundings become A) cooler. B) warmer. C) both of these D) neither of these

Q: To turn 1 gram of boiling water to steam requires A) almost as much energy as changing 1 gram of 0oC water to the boiling point. B) as much as increasing 1 kilogram of 95oC water to the boiling point. C) more energy than needed to turn 1 gram of absolute-zero ice to the boiling point. D) none of the above

Q: To turn 50 grams of boiling water to steam requires A) 50 calories. B) 500 calories C) 540 calories. D) more than 540 calories. E) none of the above

Q: To melt 50 grams of 0-degree-Celsius ice requires A) 25 calories. B) 50 calories. C) 80 calories. D) none of the above

Q: To increase the temperature of 50 grams of water by 2 Celsius degrees requires A) 0.04 calorie. B) 2 calories. C) 4.19 calories. D) 25 calories. E) 100 calories.

Q: Ice is put in a cooler to cool the contents. To speed up the cooling process, the ice can be A) wrapped in newspaper. B) drained of water periodically. C) kept away from the food. D) broken into smaller pieces. E) none of the above

Q: The cooling effect inside a refrigerator is produced by A) an electric motor that converts electrical energy to internal energy. B) compressing the refrigeration gas. C) vaporizing the refrigeration liquid. D) proper insulation. E) exchanging warmer air with colder air.

Q: A refrigerator A) produces cold. B) causes internal energy to disappear. C) transfers internal energy from inside to outside. D) transfers heat into cold. E) none of the above

Q: In a heat pump, warming is accomplished when A) condensation occurs in its coils. B) vaporization occurs in its coils. C) both of these D) neither of these

Q: In a heat pump, cooling is accomplished when A) condensation occurs in its coils. B) vaporization occurs in its coils. C) both of these D) neither of these

Q: When condensation occurs inside your bedroom window, the air outside is appreciably A) colder. B) warmer. C) both of these D) neither of these

Q: When water vapor condenses on the inside of a window, the room becomes slightly A) warmer. B) cooler. C) both of these D) neither of these

Q: Melting snow tends to A) warm the surrounding air. B) cool the surrounding air. C) neither of these

Q: To save energy while you leave your cool house for a half hour on a hot day, turn the temperature setting on the air conditioner A) down. B) up. C) off altogether. D) to room temperature.

Q: To save energy while you leave your warm house for a half hour on a cold day, turn the thermostat A) down. B) up. C) to room temperature.

Q: Hydrogen and oxygen molecules in a sample of gas have the same temperature. This means the hydrogen molecules, on average, have the same A) speed and the same kinetic energy. B) speed, but more kinetic energy. C) speed, but less kinetic energy. D) kinetic energy, but more speed. E) kinetic energy, but less speed.

Q: When a hot object makes thermal contact with a cold object, the direction of A) temperature is from hot to cold. B) internal energy flow is from hot to cold C) both of these D) neither of these

Q: A Thermos bottle has double glass walls with silver coating on the glass surfaces that face each other. The silver coating reduces energy transfer by A) conduction. B) convection. C) radiation. D) all the above E) none of the above

Q: Heat normally flows from objects of high A) internal energy to objects of low internal energy. B) temperature to objects of low temperature. C) both of these D) neither of these

Q: When coal dust is spread on snow on a sunny day A) more melting occurs. B) less melting occurs. C) no change in melting rate occurs.

Q: Substances absorb heat energy by the process of A) conduction. B) convection. C) radiation. D) all of the above

Q: The solar constant for Earth is A) 0.7 kW/m2. B) 1.0 kW/m2. C) 1.4 kW/m2. D) more than 1.4 kW/m2.

Q: The solar constant is the A) input of solar energy per square meter atop Earth's atmosphere. B) difference between solar energy atop the atmosphere and that reaching ground. C) maximum amount of energy Earth receives from the Sun.

Q: Solar power is the rate at which A) the Sun emits energy. B) solar energy is received from the Sun. C) the atmosphere absorbs energy. D) all of the above E) none of the above

Q: The amount of solar energy per square meter atop the atmosphere at right angles to the Sun's rays is about A) 700 joules. B) 1000 joules. C) 1400 joules. D) much more than 1400 joules.

Q: Solar power is used in many parts of the world for A) heating water. B) generating electricity. C) both of these D) neither of these

Q: The heat we enjoy on a sunny day is due mainly to the Sun's A) high surface temperature. B) relatively close distance. C) enormous size. D) none of the above

Q: Looking forward, common consensus will likely agree that the wisest use of fossil fuels is to A) convert them to heat and smoke. B) save them for tomorrow's materials. C) extract and sell them as quickly as possible. D) all of the above

Q: Every equation in physics reminds us of a lesson: we can never change only one thing. When we change the composition of the atmosphere we likely also change A) its transparency. B) its reflectivity. C) its average temperature. D) Earth's climate. E) all of the above

Q: If the composition of the upper atmosphere were altered to permit a greater amount of terrestrial radiation to escape, Earth would be A) cooler. B) warmer. C) quite unaffected. D) none of the above

Q: Long ago a runaway greenhouse effect transformed the planet A) Mercury. B) Venus. C) Mars. D) all of the above

Q: Which is the most abundant greenhouse gas in Earth's atmosphere? A) nitrogen. B) water vapor. C) carbon dioxide. D) none of the above

Q: If there were no greenhouse effect, Earth's average temperature would likely be A) near absolute zero. B) a frigid -18C. C) comfortably cooler. D) warmer than now.

Q: Glass in a florist's greenhouse acts as a one-way valve in that it A) lets light energy flow only in one direction. B) cuts off unwanted radiation. C) allows high-frequency waves in and blocks low-frequency waves exiting. D) is transparent only to lower-frequency waves.

Q: The planet Earth loses heat primarily by A) conduction. B) convection. C) radiation. D) all of the above

Q: Waves emitted by the Sun and terrestrial wave emissions are A) the same except for their frequencies and wavelengths. B) entirely different kinds of waves. C) identical.

Q: Which body glows with electromagnetic waves? A) the Sun B) the Earth C) you and your classmates D) all of the above

Q: When you're ready for the hottest sips of coffee, add cream A) right away. B) at any time. C) when you are ready to drink the coffee.

Q: It is commonly thought that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling A) supports this common knowledge. B) contradicts this common knowledge. C) is unrelated to this common knowledge.

Q: A blueberry pie will be a net absorber of energy when its temperature is A) higher than its surroundings. B) lower than its surroundings. C) none of these

Q: An apple pie will be a net emitter of energy when its temperature is A) higher than its surroundings. B) lower than its surroundings. C) none of these

Q: A red-hot piece of coal will cool quicker in a A) cold room. B) warm over. C) both the same.

Q: Newton's law of cooling applies to objects undergoing A) cooling. B) warming. C) both of these D) neither of these

Q: Both black and white road surfaces radiate energy. At midnight on a starry night the warmer road surface is the A) black surface. B) white surface. C) neither, as no noticeable difference.

Q: Both black and white road surfaces absorb sunlight. The warmer road surface at the end of a sunny day is the A) black surface. B) white surface. C) neither of these

Q: If a poor absorber of radiation were a good emitter, its temperature would be A) less than its surroundings. B) more than its surroundings. C) the same as its surroundings.

Q: A good reflector of radiation is a A) good absorber of radiation. B) good emitter of radiation. C) poor absorber of radiation. D) none of the above

Q: A good absorber of radiation is a A) good emitter of radiation. B) poor emitter of radiation. C) good reflector. D) none of the above