Quiz #2 Study Guide
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WORD format)
*** Chapter
2 (pps 26-31) ***
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). A
city on a coastline will have a more moderate climate than a city
located further inland.
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
atomic or molecular motions at a rate that depends on the material
(thermal conductivity)
and the temperature gradient. Examples of good and poor conductors. 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 (rising and
sinking air) and forced
convection. Free convection is a third way of causing rising air
motions in the atmosphere.
(3)Latent heat energy transport. 2nd most important
energy transport process. Six phase change
names. For
each phase change you should know whether energy is added to a material
(absorbed
from or taken from the surroundings) or taken from
the material (released into the
surroundings).
***
Chapter 6 (p. 144) or pps 49-54 in the photocopied Classnotes ***
Ideal Gas Law.
This is
a
microscopic-scale explanation of air pressure. Two equations:
P = N k T / V and P = (rho) R
T. N is the number of air molecules in
a
volume V, T is temperature and rho
is density. R and k are both constants. 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?
Ideal gas law
applications. If you heat or cool a parcel of air in the
atmosphere, Charles' law says the density
(volume)
will change in such a way that the air pressure inside the parcel
remains constant (remains the same as the pressure of the air
surrounding the parcel).
Upward and downward 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.
Sample Questions (from the Fall 2000 Quiz Packet)
Quiz #1: 5, 12,
13, 14, 16, EC3
Final Exam:
12, 22, 41, 43, 53
*** Chap.
2 (pps 31-34) ***
Static electricity and
electric fields.
Like charges repel, opposite charges attract. The pattern of electric
field vectors (arrows) drawn
around a positive charge shows the direction and strength of the force
that would be exerted on another + charge placed at any point in the
pattern. Would
the electric field at Point X, halfway between a + and a - charge point
toward the right, the left, or would the electric field be zero?
+
X
-
Electromagnetic radiation.
The most important of the 4 energy transport processes (why?).
Oscillating electric and magnetic fields that can propagate (at the
speed of light) through empty space (and other materials). 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
#2: 11, 12d&e, 13, 14, 15 Final
Exam: 15, 36
*** Chapter 2 (pps 35-43) ***
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, methane, etc. 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 2.15 & 2.16 in the text. Two relatively easy questions:
(i) What percentage of the
sunlight arriving at the top of the atmosphere reaches the ground and
is absorbed? (ii) What happens to the remaining sunlight? These
next questions are a little harder: (i) Why does the
atmosphere emit more energy downward toward the ground than upward into
space? (ii) Does the earth's surface get more radiant energy from
the
sun or from the atmosphere? (iii) Is most of the radiant energy
emitted
by the earth's surface absorbed or transmitted by the atmosphere?
Sample Questions
Quiz #2: 2, 5, 7, 8, 12a,b,&c,
EC3 Final Exam:
5, 20
Reviews
Mon., Mar. 10
Tue., Mar. 11
Wed., Mar. 12
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4-5 pm
4-5 pm
4-5 pm
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FCS 225
FCS 225
FCS 225 |