HW 2 Key
- How high is the typical pressure at the earth's surface in millibars? In
inches of mercury? In Pascals?
1013 millibars. 29.92 inches of mercury. 101325 Pascals.
- Suppose you have a sealed jar of air. If you heat the jar, how does the
pressure inside the jar change, and why?
The pressure would increase, as determined by the Ideal Gas Law. Inside of
a jar, the density is constant; therefore, increasing the temperature
increases the pressure. Physically, what happens is the molecules are moving
faster, so they hit the sides of the air with more force.
- Explain how heating the air inside of a hot air balloon causes the balloon
to float.
Inside of a hot air balloon, the pressure is constant. Therefore, as
determined by the Ideal Gas Law, heating the air inside of the balloon
decreases the density. The air inside of the balloon is now lighter than the
air around the outside of the balloon, and the balloon floats.
- Why does temperature decrease with height in the troposphere?
Temperature decreases with height in the troposphere because the source of
heat for the troposphere is the earth's surface. As one reaches higher
altitudes, one is getting farther away from the SOURCE of heat, and so the
temperature decreases.
- Why does temperature increase with height in the stratosphere?
Temperature increases with height in the stratosphere because the source of
heat for the stratosphere is absorption of ultraviolet radiation in the ozone
layer. As one research high altitudes in the stratosphere, one is getting
closer to the SOURCE of heat, and so the temperature increases.
- List at least three ways in which the troposphere is different from the
stratosphere.
There are many possible answers to this question. Some common answers
include the following: The temperature decreases with height in the
troposphere, while in increases with height in the stratosphere. The
troposphere is more density and at a higher pressure than the stratosphere
is. The troposphere is lower than the stratosphere is. The troposphere is
where weather happens, whereas no weather happens in the stratosphere. The
troposphere is very turbulent, whereas the stratosphere has very little
turbulence. The troposphere is more moist than the stratosphere is. In the
troposphere, ozone is a pollutant, whereas ozone is a natural constituent of
the stratosphere.
It is NOT acceptable to answer that the troposphere is warmer (or colder) than
the stratosphere.
- How is the heterosphere different from the homosphere? What is the name of
the level that separates these two layers of the atmosphere?
In the homosphere, atmospheric constituents are well-mixed. In the
heterosphere, all atmospheric gases tend to "settle out" into separate layers
of individual gases--that is, the gases are no longer well-mixed. These two
layers are separated by a level called the turbopause.
- A cold can of soda accumulates condensation as it sits out on the
countertop. Is the formation of the condensation warming or cooling
the drink inside the can? Explain your answer in terms of latent heat.
The formation of condensation on the outside of a can of soda is a WARMING
process. The water vapor molecules in the air have a great deal of energy,
which they must release in order to come to rest on the outer surface of the
can. This energy is released as latent heat to the environment--that is, the
can. The heat is used to warm the soda.
- Explain how the melting of ice is a cooling process.
The molecules of water in an ice crystal have very little energy. In order
to "melt" and join the liquid water, they are going to need to gain a lot of
energy. They do this by absorbing heat from the liquid. Therefore, melting
ice causes the temperature of the liquid around the ice to fall.
- Explain the difference between advection and convection.
"Convection" is moving heat by moving a heated fluid vertically.
"Advection" of heat is moving heat by moving a heated fluid horizontally.
- What is a temperature inversion? Name a layer of the atmosphere that is an
example of a temperature inversion.
A temperature inversion is a layer of the atmosphere in which
temperature increases with respect to height. The stratosphere and the
thermosphere are both good examples of temperature inversions.