Quiz #2 Study Guide

*** 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 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.  Six phase change names. For each phase change you should know whether energy is added to (absorbed from or taken from the surroundings) the material or taken from (released into the surroundings) the material that is changing phase.

Sample Questions
Quiz #1: 5, 12, EC3          Final Exam: 12, 43, 53
*** 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.  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 4th and most important (why?) energy transport process. 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. 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 2.15 & 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 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

*** Chapter 2 (pps 43-51) & photocopied notes (pps 73-80) ***
Seasons (material from this section WILL be on the quiz)
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 the plane of 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 (material from this section WILL NOT be on the quiz)
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 #3: 4, 8, 15, EC2          Final Exam: 16

Reviews
Mon.
Tue.
Wed.
 4-5 pm
4-5 pm
4-5 pm
 Soc Sci 222
FCS 225
FCS 225