QUIZ 2 REVIEW: Answers

Temperature & Energy:

  1. Give two examples of kinetic energy.

    2. A raindrop falling through the air.

    The random motions of the gas molecules in the class room.

  2. Give an example of potential energy.

    3. A cloud drop (liquid water) floating in the atmosphere above the ground.

    The internal energy that a water molecule has gained when it changes its phase from liquid to vapor. This is what we called the Latent energy

  3. Give an example of the conversion of either kinetic energy to potential energy or vice versa.

    4. As a raindrop falls through the atmosphere, it is moving (kinetic energy) because it is pulled downward due to gravity (potential energy).

  4. The temperature of an object is a measure of the random motion of the molecules in the object.
  5. A molecule that had no random motions would have a temperature of

    6. -273 Celsius.

  6. The forecast high temperature in Sydney Australia for today is 68 F. What is this in Celsius?

    7. C=(F-32)/1.8=(68-32)/1.8=(36)/1.8=20C

  7. The forecast low temperature in Fairbanks, Alaska for today is 2 C. What is this in Celsius?

    8. F=32+Cx1.8=32+2x1.8=35.6F

  8. What is the process that produces the radiation that the earth receives from the sun?

The radiation that Earth receives from the sun is energy given off during the nuclear fusion process of combining light atoms to form heavier atoms.

Energy Transport:

  1. Give an example of the following methods of energy transport in the atmosphere:
    1. radiation – Sun light
    2. convection – Warm air rising
    3. conduction – Air molecules touching the ground that gain energy when they collide with the ground.
  2. The surface temperature on Venus is 700 K. At what wavelength would the most radiant energy be emitted from the surface?

    3. Wein’s Law gives the relation between the temperature of an object and the wavelength at which it radiates the most energy.

    Brightest Wavelength = 2897/T=2897/700=4.1 micrometers

  3. If an object with a temperature of 700 K emits 30 Watts per square meter (30 W/m2), then how much energy will it emit if the temperature is increased to 770 K?

Stefan-Boltzman’s Law states that the total amount of energy radiated by an object is proportional to the temperature of the object raised to the fourth power. In this case the object initially has a temperature of 700 K and emits 30 W/m2. How much more energy will be radiated if the temperature is raised from 700 K to 770 K.

So the final amount of energy radiated is about 1.5 times the initial amount radiated, or

Final Radiated Energy = 1.5 x Initial Radiated Energy

= 1.5 x 30 W/m2

= 45 W/m2

 

 

 

Global Energy Budget:

  1. List the ways in which the atmosphere can be heated (there are 4) starting with that which provides the most amount of energy to that which provides the smallest amount.
    1. Absorption of radiation emitted by the Earth (longwave)
    2. Latent Heating by H2O
    3. Absorption of solar radiation (shortwave)
    4. Sensible Heating by the Earth
  2. For each of the items in the list from question 1 directly above, determine which method(s) of energy transport given in question 1 of "Energy Transport" are involved.
    1. Radiation, Conduction
    2. Convection, Conduction
    3. Radiation, Conduction
    4. Convection, Conduction
  3. How is the surface of the Earth heated and what does the largest part of the heating?
    1. Absorption of solar radiation (shortwave)
    2. Absorption of radiation emitted by atmosphere (longwave). This does the most heating on a global basis.
  4. What gases in the atmosphere absorb shortwave solar radiation?
    1. O2
    2. O3
    3. H2O
    4. CO2
  5. What causes the temperature to increase with altitude in the stratosphere?

    6. The absorption of solar radiation by O2 during the source process of O3 & the absorption of solar radiation by O3 during the sink process of O3.

  6. If in the future the albedo of the Earth/Atmosphere System remains the same, but the amount of CO2 in the atmosphere increases, what will happen to the amount of radiation absorbed by the Earth/Atmosphere System?

    7. The radiation absorbed by the Earth/Atmosphere System will be that amount of radiation that is intercepted by the Earth/Atmosphere that is NOT reflected back to space (the albedo). In this case the albedo remains the same, so the total amount of radiation energy that is absorbed by the Earth/Atmosphere System would also remain the same. Using our numbers for the Global Energy Budget, the albedo is 30%, so 30% of the solar radiation that is intercepted by the Earth/Atmosphere system is reflected back to space and the remaining 70% is absorbed by the Earth/Atmosphere System.

  7. Cloudy nights are generally warmer than clear nights because the clouds emit more radiation in the Longwave Atmospheric Window region than does the atmosphere. This additional energy is absorbed by the surface and warms it.
  8. There are two surfaces with the same temperature; one is covered with ice and the other is bare soil. The amount of shortwave solar radiation measured by a satellite looking at the two surfaces would be greater for the ice surface.
  9. There are two surfaces with the same temperature; one is covered with ice and the other is bare soil. The amount of radiation in the longwave atmospheric window measured by a satellite looking at the two surfaces would be the same for both surfaces.