NATS 101 Quiz 2 Study Guide
Chapter
2 (pps 26-30)
Energy, temperature and heat.
Kinetic energy - energy of motion. Temperature (which scale?)
provides a measure of the average kinetic energy of the atoms or
molecules in a substance. Heat energy is the total kinetic energy
of all the atoms or molecules in a material. Energy units:
calories.
What is the relationship between energy added to (or removed from) an
object, ΔE, and the
temperature change, ΔT,
that
results? Specific heat or thermal capacity. Water has a
relatively high specific heat (4 or 5 times higher than soil).
Temperature scales.
Fahrenheit, Celsius, and Kelvin (absolute) scales.
You should know the temperatures of the boiling point of water at sea
level and the melting point of ice (same as the freezing point of
water) on all three scales. The global
average surface temperature of the earth is about what
temperature on the Kelvin scale?
Energy transport.
(1) Conduction. Energy is transported from hot to cold by random
motions at a rate that depends on the material (thermal conductivity)
and the temperature gradient. Examples of good and poor conductors. Is
air a good or a poor conductor?
An object with high thermal conductivity will often feel cold to the
touch because it rapidly conducts energy away from your body.
(2) Convection. Energy transport by organized motion of atoms or
molecules (works in gases and liquids but not solids). Free and forced
convection. Free convection is a third way of causing rising air
motions in the atmosphere (why are rising air motions important?). Free
convection in the atmosphere.
(3)Latent heat energy transport. Six phase change
names. For
each phase change you should know whether energy is added to (absorbed
or
taken from the surroundings) or taken from (released into the
surroundings) the material that is changing phase (see Fig. 2.2 in
text).
Controls of Temperature.
You should understand how latitude, proximity to land or ocean, and
altitude affect the annual average temperature and the annual range of
temperature at a particular location. Where are the hottest and
coldest locations on earth?
Which city in the figure above at left (all found at the same altitude)
would have the hottest summertime temperatures? Which city would
have the coldest wintertime temperatures? Which city would have
the largest annual range of temperature? Which city would have
the smallest annual range of temperature?
All three cities in the figure above at right are located at the same
latitude. Which city would have the smallest annual temperature
range? Which city would have the lowest annual average
temperature?
Which city would be hottest in the summer? Which city would be
coldest
in the winter?
Sample Questions: Quiz
#1: 2, 4, 7, 10, 13, 18, 20 Quiz #2: 7,
15 Final: 3, 36, 42
Chap.
2 (pps 31-34)
Static electricity and
electric fields.
Like charges repel, opposite charges attract. The electric field drawn
around a positive charge shows the direction and strength of the force
that would be exerted on another + charge placed nearby.
Electromagnetic radiation.
The 4th and most important (why?) energy transport process.
Oscillating electric and magnetic fields that can propagate (at the
speed of light) through empty space. Radiation can be produced by
moving charges. You add energy to cause the charges to oscillate and
produce the radiation. Energy reappears when the resulting radiation
causes electrical charges somewhere else to move. Wavelength is one way
of distinguishing between different types of radiation (frequency is
another). Would a slowly-oscillating charge produce long- or
short-wavelength radiation? Would this be a relatively high- or
low-energy form of radiation? Electromagnetic spectrum. We will mostly
be concerned with ultraviolet (UV), visible (VIS), infrared (IR) light.
What is the wavelength interval for visible light? What is white light?
Does red light have longer, shorter, or the same wavelength as blue
light? Wavelength units.
Rules governing the emission of
radiation.
What determines how much and what type of radiation an object will emit
(the same variable is found in both the Stefan-Boltzmann law
and Wien's
law)? A light bulb connected to a dimmer switch was used to
demonstrate. Radiant energy emitted by the earth (300 K) and sun (6000
K).
Sample Questions: Quiz
#1: 6, 9 Quiz #2: 14
Final Exam: 11, 50
Chapter 2 (pps 35-42)
Radiative equilibrium
Energy balance. Incoming radiant energy (sunlight) is balanced by an
equal amount of (but not necessarily the same kind of) outgoing radiant
energy. Temperature remains constant.
Filtering effect of the atmosphere
Does the atmosphere mostly absorb, selectively absorb, or mostly
transmit UV, VIS, and IR radiation? What gases are important in each
case? What does the term window mean? What property makes water vapor,
carbon dioxide, and other gases greenhouse gases?
Greenhouse effect (simplified view)
With an atmosphere (containing greenhouse gases), the
temperature of the earth's surface is warmer than it would be without
an atmosphere. H2O, CO2, and other greenhouse
gases selectively absorb
IR radiation. The atmosphere in turn radiates IR radiation into space
and back toward the ground. How is it possible for the earth's surface
to radiate away more energy than it receives from the sun and still be
in energy balance? What effects do clouds have on nighttime and daytime
temperatures? Why?
Earth-atmosphere energy budget
See Figures 2.13 & 2.14 in the text. What percentage of the
sunlight arriving at the top of the atmosphere reaches the ground and
is absorbed? What happens to the remaining sunlight? Why does the
atmosphere emit more energy downward toward the ground than upward into
space? Which of the four energy transport processes carries the most
energy from the ground to the atmosphere and into space?
Sample questions: Quiz #2: 1, 4, 5, 8, 10, 12, EC1, EC3
Final Exam: 20, 28
Chapter
2 (pps 42-51) & photocopied notes (pps 73-80)
Seasons
Earth's orbit around the sun. When is the earth closest to and furthest
from the sun? What is the earth's orientation, relative to its orbit
around the sun, on the solstices and equinoxes? When do the solstices
and equinoxes occur? The changing orientation of the earth means that
the angle at which sunlight strikes the ground will vary during the
year. Is more energy delivered to the ground when the sun is high or
low in the sky? Why (there are a couple of reasons)? What is the other
factor that determines how much energy arrives at the ground during the
day?
Sunpath diagrams
We looked at several examples of how the sun's path in the sky during
the day changes depending on location and the time of year. You should
have a good idea of how the sun's path in the Tucson sky changes during
the year. For a given date (one of the solstices or equinoxes), you
should be able to say where (latitude) the sun will be overhead at
noon, where the days are more than 12 hours long, and where the days
are less than 12 hours long. How long are the days at present in
Tucson? Are the days getting longer or shorter? Is there any location
on earth where the length of the day does not change during the year?
How often during the year will the sun be overhead at noon at the
equator? Click here
to test yourself on some of this material.
Where are the Antarctic and Arctic circles, the Tropics of
Cancer and Capricorn? What is their significance?
When during the year
would you expect the sun to rise in the northeast, due east, and the
southeast? Where would you look to see the sun at noon in Sydney,
Australia?
Does the greatest seasonal change occur at high or low
latitude? The maximum amount of energy reaches the ground at what
latitude during the summer?
Sample questions: Quiz #2:
2, 6, 13
Final Exam: 29
Reviews
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Chávez (Econ) 301
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Chávez 301
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