Quiz #1 Study Guide
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Questions on Quiz #1 will come from topics on this study guide and material on the Practice Quiz Study Guide.  Be sure also to review the questions on the Practice Quiz and the Optional Assignments.

Mass, weight, density, and pressure (20 pts).  Mass is the amount of a particular substance. On the earth gravity pulls downward on a mass producing weight. Pressure at any level in the atmosphere is a measure of the weight of the air above (this is one way of thinking about and understanding pressure). Pressure is defined as force divided by area and acts like a force (a force that pushes upward, downward, and sideways). Common pressure units and typical sea level pressure values.   What instrument is used to measure air pressure? About when was it invented? Pressure and air density (density = mass divided by volume) both decrease with increasing altitude (you should be able to explain why). What relationship is there between the rate of pressure decrease and air density (i.e. does pressure decrease most rapidly in high or low density air)?

Layers of the atmosphere (15 pts).  Troposphere: lowest layer in the atmosphere, decreasing temperature with increasing altitude (why is the warmest air found near the ground), contains most of the water vapor and clouds, can be unstable (strong vertical air motions possible). Tropopause. Stratosphere: there's an isothermal layer and a temperature inversion layer (what causes air to warm in the stratosphere), stable layer, contains the ozone layer. Approximate altitudes of these layers. Units: meters, kilometers, feet, miles.

Ideal Gas Law (10 pts). This is a microscopic-scale explanation of air pressure. Two equations:

P = N k T / V     &     P = ρ R T

N is the number of air molecules in a volume V, T is temperature and ρ is density.  R and k are both constants (you can pretty much ignore them).  You should be able to determine what will happen to the pressure in a rigid container or something flexible like a balloon if you change the variables in the equation above.  What variables could you change together in such a way that the pressure would stay constant?  Charles' Law.  In the atmosphere why is warm air normally low density air (cold air normally high density air)?

Upward and downward forces (15 pts).  Vertical forces acting on air parcels (the strength of one of the forces depends on the air inside the parcel, the other on the air outside the parcel). These two forces are usually in balance. What happens to the balance when you warm or cool a parcel of air?  Basically you should be able to explain why a balloon of hot low density air rises and a balloon of cold high density air sinks.

Archimedes Law (0 pts).  An object immersed in a fluid (this can be a liquid like water or a gas like air) experiences an upward bouyant force that is equal to the weight of the fluid displaced by the object.  Basically objects that are less dense that the fluid around them float, objects that are denser than the fluid surrounding them sink.  What causes the upward bouyant force (it's the same upward force mentioned in the section above).

Sample questions ( from the Fall 2000 quiz packet )
Practice Quiz: 16, EC2, EC3     Quiz #1: 1, 3, 13, 14, 16, 17, EC2          Final Exam: 6, 11, 19, 22

Station model notation (15 pts). How and where are the following weather variables plotted: cloud cover, temperature, dew point temperature (typical values for Tucson), wind direction and speed, common weather symbols (rain, snow, fog, rain shower, thunderstorm, tropical storm and hurricane), pressure.  Units. After pressure is measured, what important adjustment is made before the pressure is plotted on the surface map? Why is that necessary? Average and typical range of sea-level pressure values.

Surface weather maps (15 pts). A new map is prepared hourly. What time zone or time reference is used? 24-hour clock.  Isobars and isotherms. Small horizontal differences in pressure cause the wind to blow. Air motions around high and low pressure centers (northern hemisphere). Strong and weak pressure gradients. Convergence and divergence. Rising and sinking air motions.

We might not have time to cover the following material in both sections of the class, it won't be on the quiz
How do wind motions around highs and low affect the temperature pattern? Cold fronts and warm fronts (where is the warm and cold air, what direction are the fronts moving).

Sample questions
Practice Quiz: 2, 10, 11, 14, 19     Quiz #1: 6, 7, 8, 9, 10, 11     Final Exam: 7, 10, 34, 47, 52

Reviews
Mon., Sep. 17
 4 - 5 pm
 Haury (Anthropology) 216
Tue., Sep. 18
Tue., Sep. 18 		2 - 2:50 pm
4 - 5 pm
 Saguaro Hall 225
Haury (Anthropology) 129
Wed., Sep. 19
 4 - 5 pm
 Harvill  204
The Mon. review is nominally for the MWF class, the W review is for the T Th class