Chapter 24 review


    Vocabulary
    Match each word to the sentence where it best fits.
      Section 24.1

      Newton’s law of cooling convection
      heat transfer thermal conductivity
      thermal equilibrium 
      1. The study of how thermal energy moves is called _______.
      2. When two objects are in _______, no heat will flow between them.
      3. As the temperature difference between two objects becomes large, the heat flow between them increases according to _______.
      4. _______ is heat transfer that occurs through the motion of matter, such as forced air in a building’s heating system.
      5. A material with a higher _______ can more readily conduct heat.
      Section 24.3

      blackbody emissivity
      heat transfer coefficient 
      1. An object with a/an _______ of zero emits no thermal radiation from its surface.
      2. A/An _______ absorbs all of the thermal radiation that is incident upon it.
      3. The measure of the rate of heat flow between a surface and a fluid is called the _______.
      Conceptual questions
        Section 24.1
        1. How many different ways can heat be transferred? Name and describe each one.
        2. A hot cup of coffee is cooling to room temperature over the course of 20 minutes following a standard cooling curve. Which statement best represents its cooling behavior?
          1. The coffee’s temperature changes fastest when the temperature difference between the coffee and the room air is smallest.
          2. The coffee’s temperature changes fastest when the temperature difference between the coffee and the room air is largest.
          3. The coffee’s temperature changes at a constant rate.
        1. Using the term “thermal conductivity,” explain why a copper ladle in a pot of boiling water feels hotter than a wood ladle.
        2. Easy When investigating the heat transfer properties of a house, such as in Investigation 24A on page 1407, you want to maintain an inside temperature of 20°C using a 2,500 W heater during the winter.
          1. What are the variables related to the design of the house that can be varied to change the heat transfer properties of the house?
          2. How would you pose a well-defined question to investigate what insulation is required?
          3. When determining the optimal size for the surface area of the walls of a house, one student obtained a value of 1.7 m2. Is this a reasonable answer?
          4. When another student was setting the parameters for a house, she entered an area for the windows that was 1% of the area of the walls. Is this a reasonable design?
          5. Jeremiah wanted to use the simulation to model the heat flow for his own house. What measurements and observations would he need to implement his idea for an investigation? What equipment does he need to make those measurements?
          6. Jeremiah poses the question for his investigation, “Is my house radiating energy?” Is this a well-defined question for his investigation with the simulation?
          7. Is the simulation an appropriate kind of technology for Jeremiah to determine how much relative energy is flowing out of the north side of his house as compared to the south side of his house at noontime?
        Section 24.2
        1. Identify each of the following actions with conduction or convection.
          1. blowing on a spoonful of hot soup to cool it
          2. shoving a warm can of soda into a bucket of ice to cool the soda
          3. replacing thin, single-pane windows with thick, double-pane ones to better insulate your home
        2. Decide whether each of the following statements correctly describes the process of conduction, convection, or both.
          1. It requires a temperature difference to transfer thermal energy from one place to another.
          2. The larger the temperature difference between two places, the faster it transfers thermal energy.
          3. It operates efficiently in fluids but not in solids.
          4. It will burn your skin if you grab a red-hot piece of metal with bare hands.

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