Earth Science Archive

This page has all the class notes from previous assignments.

Homework for Wednesday, March 18.
Chapter 14 - Earthquakes and Earth's Interior

Things to remember:
-P waves travel faster than S waves.
-S waves do more damage.
-S waves do not travel through liquids.
-Because S waves do not travel through liquids, and S waves don't show up on seismometers about 2/3s of the way around the world from an earthquake, it is believed the outer core is in the liquid state.
-This is called the S wave shadow zone.
-There is also a narrow zone (kind of a ring) opposite from an earthquake where P waves also do not show up - the P wave shadow zone.
-The P wave shadow zone is caused by the P waves being bent ('refracted') at the margin of the mantle and outer core.
-Our knowledge of earthquake waves greatly increased with underground atomic bomb testing, beacuse we had very precise information on exactly where and when those atomic bomb tests occurred.

Homework for Thursday, March 19
Chapter 19 - Weather Variables and Heating of the Atmosphere

Things to remember:
- Insolation is short for "Incoming Solar Radiation".
- Insolation means "sunshine" plus all the invisible forms of energy from the Sun.
- Not the same as "insulation" which is the pink stuff we put in the ceilings and walls to prevent heat loss.
- Angle of Insolation means how high in the sky is the Sun.
- The Sun appears highest at Solar Noon on any given day.
- Angle of Insolation is greatest on the Summer Solstice (usually June 21 in the Northern Hemisphere.)
- Duration of Insolation means how many hours of sunlight are there in a day.
- The Duration of Insolation is greatest on June 21 and least on December 21.
- A barometer measures air pressure.
- Air Pressure = Air Density.
- High Pressure = High Air Density.
- Two things make the air less dense: Heat and Water Vapor.
- Low Pressure air is hot and humid.
- High Pressure is cold and dry.
- Fog is a cloud on the ground.
- Clouds are made of water droplets and/or ice crystals.
- Water vapor is invisible.
- Clouds can be seen, meaning they are made of water droplets or ice crystals.
- Relative Humidity is a measure of water vapor content in the air, adjusted for the temperature of the air.
- When it is hotter, more water can evaporate.
- So 100% humidity varies depending on the temperature.
- When 100% humidity is reached, water vapor condenses causing clouds to form, and possibly rain or snow.
- If it is cold, it doesn't take as much water vapor as when it is hot to reach 100% humidity.
- A thermometer measures "average kinetic energy" - in other words, the 'motion' of the atoms and molecules.
- Weather is the term used to describe the daily changes in heat and humidity in the atmosphere for an area.
- Weather never quite repeats - every day brings slightly different conditions across the Earth.
- Climate means long term patterns in weather, because of a number of factors to be discussed in a later chapter.
- When short wave radiation from the Sun hits the Earth, some of the shortwave light energy is converted to longwave heat energy.
- Greenhouse effect refers to certain molecules (water vapor, CO2, methane, CFCs, and others) that slow the loss of heat in the atmosphere to outer space.
- Greenhouse effect can be both natural or manmade.
- A certain amount of Greenhouse effect is good for Earth; it keeps the Earth from getting too cold for life.
- Manmade Greenhouse effect is unnatural, causing heating that is out of balance with the natural processes of photosynthesis.
- An anemometer measures wind speed.
- A wind (or weather) vane indicates the direction the wind is coming from.
- Winds are named by where they come from (A westerly breeze comes from the west, etc.)
- Heat can be transferred through conduction, convection or radiation.
- Heat always flows from "Source to Sink" - from where there is more heat to where there is less heat.

Homework for Friday, March 19:
Chapter 20 - Humidity, Clouds and Atmospheric Energy

Things to remember:
- "Absolute humidity" refers to the actual amount of water wapor in an air sample.
- "Relative humidity" (discussed in Chapter 19) refers to the amount of water vapor in the air, adjusted for the temperature.
- Absolute humidity units are usually (mg of water vapor/cubic meter of air) or similar units.
- Relative humidity units are given in percent.
- Dew point temperature is the temperature you have to cool air to in order for water to start to condense.
- When dew point is reached, relative humidity is 100%.
- A hygrometer consists of 2 thermometers, one is the 'dry bulb' and one is the 'wet bulb.'
- Evaporation on the wet bulb causes its temperature to drop (unless it is already at 100% relative humidity.)
- Using p. 12, and noting the difference between the dry bulb and wet bulb temperatures allows for a determination of dew point and relative humidity.
- A hygrometer is also called a sling psychrometer when the instrument is swung around in the air to create a 'breeze' on the wet bulb.
- Evaporation (or vaporization) occurs when heat energy causes liquid water to change to the vapor state and enter the atmosphere.
- Water can also change directly from ice to water vapor (like in the Gobi Desert). This process is called 'sublimation.'
- Specific heat refers to how individual materials respond to heating and cooling. See p. 1.
- Liquid water requires more heat transferred to raise (or lower) its temperature than any other common material.
- If a substance is hard to heat, it is also hard to cool.
- Because of the high specific heat of water, once heated, water loses that heat quite slowly.
- The high specific heat of water is one reason why weather is so variable.
- Any interactions between water and land usually involve a difference in temperature and water vapor content, and a transfer of heat, resulting in clouds and/or precipitation.
- What we call 'weather' is simply the endless exchange of heat and water vapor between different air masses.
- A lake effect storm occurs when water vapor from a large body of water is pushed onto cooler and drier land, causing condensation and rain or snow.
- Transpiration is the loss of water vapor by plants during photosynthesis.
- Evapotranspiration means the combined effect of both plants transpiring and water evaporating from the surface of the land or ocean.
- Latent heat is heat lost or gained during the phase changes of a material. See p. 1.
- The temperature of a material does not change during a phase change because all the energy goes into the phase change.
- You add energy to either melt ice or evaporate water. ("Energy gained.")
- You take away energy to freeze or to condense water. ("Energy released.)
- When ice is melting, or water is evaporating, a LOT of energy goes into changing the state of matter.
- Evaporating water takes a staggering amount of heat energy (measured in 'joules.')
- Boiling is vaporization when the 'average temperature' has reached 100 degrees C under normal atmospheric pressure.
- Like evaporation, boiling takes a lot of energy.
- This is why you have to wait a long time from when water is being heated ("A watched pot never boils" refers to this long time it takes.)
- Once evaporated, the air carries that water vapor (along with its latent heat) until ithe water vapor condenses.
- It then releases all that latent heat at the new location.
- So if you think about a hurricane that starts in very warm seas, the water vapor from the ocean is transferred to the storm.
- This released latent heat causes the winds in clouds to move upward because heated air rises (low pressure), which sets off a chain reaction of more and more condensation as the clouds reach higher altitudes (where temperatures are still colder.) This also increases wind speeds. (More on that later.)
- A condensation nucleus (plural: nuclei) is a small bit of dust, pollen, or other particles that gives water vapor a surface to condense on.
- So when it rains, the rains is literally washing the air clean of these particles as they fall to the ground.


The week of March 23 - March 27:
I will be adding some notes (though the book covers the material pretty well.)
We will need to check the quiz procedure. I think it will work fine.

Monday, March 23
Chapter 21 - Air Pressure and Winds

Tuesday, March 24
Review Quiz 1
Link sent. Submit when completed.
Home Lab 1 (Sent in group email.)
Office Hours - Use the Group email - "Wilder Office Hours" - for now. Try to submit questions between 10 and 12 (though I will respond anytime.)

Wednesday, March 25
Chapter 22 - Weather Maps
- Many people are keeping up, but please take the online quiz if you haven't.
- Get back work in, please.
- Continue with book work, as assigned.
- The first 'Take Home Lab 1' is going nicely - Take your own photos - not from the web.
- Try to be specific on how your photos relate to Earth Science (think of specific terms we have used this year.)
- The Home Lab 1 is due next Tuesday (March 31).

Thursday, March 26
Chapter 23 - Weather Hazards and the Changing Atmosphere
- Continue with bookwork.
- If you haven't taken the online quiz - check your email for the link (I can't put that on this page.)
- Home Lab 1 - Photo Lab - try to take your own photos and definitely write your own captions/descriptions.
- For the Photo Lab, try to incorporate specific terms that relate to the course. Be thoughtful about that.
- All the photos and descriptions will be uploaded to a shared document.
- The photos have been fun to see! Missing the district...
- Quiz tomorrow on new material (Weather.)

Friday, March 27
New Content Quiz 1 - Link has been shared!
Chapter 24 - Patterns of Climate