Title: GS 106 CU4 Answer Key
Course: SkillsCom GS 106 14.0 > Section: Credit Unit 4 Competency Assessment

16-1 through 20-1

16) Describe the greenhouse effect using the words and phrases UV, re-emits, greenhouse gases, and infrared.

Answer: The greenhouse effect occurs as UV rays are emitted to Earth, once the hit earth they can either be reflected by things like clouds or ice, or they can be absorbed by the Earth’s surface. This energy is then reemitted by the Earth’s surface into the atmosphere as infrared radiation. These infrared rays are absorbed by greenhouse gases in the atmosphere and the greenhouse gases then reemit infrared back toward the Earth. The presence of these infrared emitting gases warms the atmosphere allowing it to be livable by most life.

CUA 4 Question #16 - 1 | Student uses all 4 words and phrases to correctly describe the greenhouse effect 4 pts | Student uses only 3 words or phrases to correctly describe the greenhouse effect 3 pts | Student uses only 2 words or phrases to correctly describe the greenhouse effect 2 pts | Student uses only 1 word or phrase to correctly describe the greenhouse effect 1 pt | Insufficient 0 pt

17) Name and describe 2 ways in which air lifting occurs and the weather associated with it.

Answer: There are actually 3 types of air lifting in the atmosphere, the student can have one of the following 3:

Orographic Lifting: This is when air mass is forced up a large obstruction, like a mountain or a volcano. As the air mass if forced over the obstruction, any water vapor that is in the air mass condenses causing precipitation to fall. After the air passes across the mountain range, it will begin to sink and dry out, and in some cases greatly warm the surrounding air. Because of this areas in front of a mountain tend to have wetter climates and areas on the leeward side of the mountain tend to be drier.

Frontal Wedging (lifting): Frontal wedging happens as air (or wind) flows into an area of contrasting temperature; cold fronts where colder air moves into and area or warm fronts where warmer air moves into and area. This can either be referred to as a cold front or a warm front. Cold air is denser than warm air, and as a result, it undercuts and pushes the warm air rapidly upwards and can sometimes result in strong to severe thunderstorms. The warm air of a warm front will rise more slowly over the cooler air at the surface providing clouds and showers to form along and ahead of the warm front.

Convectional Lifting: As convection occurs, warm air at the surface begins to rise, as it rises it cools, then as it cools it condenses and falls back towards earth, creating a convection cycle. This occurs generally in fair weather, but if there is a lot of moisture present the weather could be much more violent, like thunderstorms.

CUA 4 Question #17 - 1 | Student correctly identifies and describes the two air lifting processes and their associated weather 4 pts | Student correctly identifies the two air lifting processes and their associated weather but only correctly described one air lifting process 3 pts | Student correctly identifies the two air lifting processes and their associated weather but does not correctly describe either air lifting process 2 pts | Student correctly identifies only one air lifting processes and its associated weather and does not correctly describe either air lifting process 1 pts | Insufficient 0 pt

18) Choose 2 positive feedback loops seen during the current climate change.

Answer: One positive feedback loop would be the melting of glaciers. As the glaciers melt the uncover areas that have a lower albedo, or lower reflection, things like grass or rock. This newly uncovered area will absorb more heat, causing more snow to melt, and uncovering more lower albedo area. This causes ice to melt at an increasing rate. Another positive feedback would be the melting of permafrost. As permafrost melt it puts methane, a greenhouse gas into the air. As more methane goes into the air, the temperature will increase causing more permafrost to melt and releasing more methane gas to accumulate in the atmosphere. This causes permafrost to melt at an increase rate and this same increase of methane occurs as the ocean warms and deep-sea methane deposits melt. Another possible positive feedback loop would be that as the world warms soil decay of grasslands increases. Decay uses oxygen and creates CO2, which in turn will enter the atmosphere making the world warmer and causing more decay. This process causes the decay to happen at an increased rate. The last feedback loop is as water warms CO2 is released from the ocean and this CO2 goes into the atmosphere. That, in turn, causes enhanced greenhouse effect and warming, which causes more CO2 to leave the ocean, again causing a feedback loop.

CUA 4 Question #18 - 1 | Student correctly describes positive feedback loops seen in climate change 4 pts | Student correctly positive feedback loops seen in climate change but misses several key points 3 pts | Student correctly describes one positive feedback loop seen in climate change but not both 2 pts | Student correctly describes one positive feedback loop seen in but not both and misses several key points 1 pts | Insufficient 0 pts

19) Describe in detail how raindrops form using the following words and phrases: cloud condensation nuclei, condense, water vapor and updraft.

Answer: Raindrops begin forming after condensation in the atmosphere. When an air parcel rises and cools it hits the dew point and the water condenses on cloud condensation nuclei, basically little particles of dust in the atmosphere. When condensation first occurs the water particles are very small and are to light to fall because of the vertical movement of air, or updraft. But as these particles are pushed upwards they run into each other and coalesce. When enough water droplets come together they will eventually become heavy enough to overcome the updraft and the raindrops will fall toward Earth.

CUA 4 Question #19 - 1 | Student uses all 4 words and phrases to correctly describe in detail how raindrops form 4 pts | Student uses only 3 words or phrases to correctly describe in detail how raindrops form 3 pts | Student uses only 2 words or phrases to correctly describe in detail how raindrops form 2 pts | Student uses only 1 word or phrase to correctly describe in detail how raindrops form 1 pt | Insufficient 0 pt

20) Name and describe the bottom two layers of the atmosphere and discuss what makes them most important for life on Earth.

Answer: The first layer is the troposphere it ranges between 0km and 17km, is the densest layer of the atmosphere and cools as one moves higher into the atmosphere. This layer is particularly important to life because it is where all weather happens, including rain and wind, and is also important because the greenhouse gases are there creating the greenhouse effect. The second layer is the stratosphere that is from 17 km and get warmer with height. This change in temperature is due to the presence of the ozone layer, which absorbs UV rays. The ozone particles vibrate as the absorb UV rays and that increases the temperature in the ozone. The ozone layer is very important because it protects life from harmful UV rays of the sun.

CUA 4 Question #20 - 1 | Student correctly identifies and describes the bottom two layers of the atmosphere and tells what makes them most important for life 4 pts | Student correctly identifies and describes the bottom two layers of the atmosphere but doesn’t tell what makes them most important for life 3 pts | Student correctly identifies and describes one layer of the atmosphere and tells what makes it most important for life but not both layers 2 pts | Student correctly identifies and describes one layer of the atmosphere but does not tell what makes it most important for life and does not identify or describe the other layer 1 pts | Insufficient 0 pt

16-2 through 20-2

16) Describe relative humidity in detail. What happens to relative humidity when an air parcel warm or cools if the amount of water vapor in the parcel stays the same?

Answer: Relative humidity is calculated by dividing the amount of water present in an air parcel by the amount of water the air parcel can hold and then you multiply that by 100 to get a percentage number. When an air parcel cools without change to the water present in the air parcel then the relative humidity increases. When an air parcel warms without change to the amount of water present in the air parcel then the relative humidity decreases.

CU 4 Question #16 - 2 | Student correctly describes relative humidity and states what happens to an air parcel’s humidity as it increases and decreases in temperature 4 pts | Student correctly describes relative humidity and states what happens to an air parcel’s humidity as it increases and decreases in temperature but misses several key points 3 pts | Student correctly describes relative humidity and states what happens to an air parcel’s humidity as it increases or decreases in temperature, but not both temperature changes 2 pts | Student correctly describes relative humidity but does not state what happens to an air parcel’s humidity as it increases or decreases in temperature 1 pt | Insufficient 0 pt

17) Choose two types of data that are used to study climate and describe how the data is collected and what kind of information it can reveal.

Answer: The students can have 2 of the following types of data:

1) Historical records can be used to find the how climate has changed all over the Earth within historical times. The data is collected through reading historical documents.

2) Tree Rings: Tree rings can be used to understand the climate of a given year when the tree was growing. For instance, when there is more precipitation in a year the tree ring will be thicker. When there is less water then the ring is thinner. You can even use dead trees for this as long as you date the tree.

3) Plant pollen: Plant pollen accumulates in the bottom of lakes. Based on climate, certain plants are able to grow in certain areas, so as climate changes in an area, say from wet to dry, then the pollen in lake sediments will show those changes. This data is collected through lake cores.

4) Oxygen isotope ratios in glacial ice: Ice cores are taken to study climate change and the ice is studied by checking the chemical composition of the water in the ice. When temperature is warmer then more of the heavier isotope of O18 is incorporated in the forming ice. When the climate is colder then there is less O18 incorporated into the ice. (they could also theoretically say the same thing about bubble in the ice and CO2)

5) Glacial Evidence: Glacial evidence can tell us when glaciers were around and their various advance and retreat. Geologists can map these movements. Also, if there are any old logs in the glacial evidence it can be dated using carbon 14 dating.

6) Plankton and Isotope in Ocean Sediment: Ocean sediments can be collected through sediment cores. Shells in the sediment cores can show us several things, 1) the species of animal, which can be either cold water or warm water species and 2) the composition of the animal’s shell. When its colder, animal shells will have more O18 in their composition and in warmer times the animal shells will have less O18.

7) The Rock and Fossil Record: Fossils that are collected by geologists can be identified and geologists can compare the modern animals to the fossils to give us an idea of the climate the rock formed in. Also, the type of rock or the features in the rock can tell us something of the environment, like fossilized sand dunes can show a desert environment.

CUA 4 Question #17 - 2 | Student correctly identifies and describes two types of data that are used to study climate, how it is collected and what information it reveals 4 pts | Student correctly identifies and describes two types of data that are used to study climate, how it is collected and what information it reveals but miss several key points 3 pts | Student correctly identifies and describes one type of data that is used to study climate, how it is collected and what information it reveals but not both 2 pts | Student correctly identifies and describes one type of data that is used to study climate, how it is collected and what information it reveals but not both and misses several key points 1 pts | Insufficient 0 pt

18) Choose 2 carbon sinks and discuss the processes that place carbon into these sinks and remove carbon from these sinks.

Answer: There are a few carbon sinks, the student need only pick two:

One carbon sink is the atmosphere. Carbon gets into the atmosphere by burning fossil fuels, respiration, decay, and interactions with the ocean. Carbon is can be removed from the atmosphere by being dissolved into the ocean and also plants can photosynthesize removing carbon from the atmosphere.

Another carbon sink is the biosphere. Any carbon-based life forms contains carbon when they are living. Also, plant photosynthesize, so they also absorb CO2 from the atmosphere and incorporate that CO2 into their makeup. Carbon can be released from this sink through decay of carbon-based materials, the removal of trees and plants, and the burning of trees and plants.

Another carbon sink is the hydrosphere. CO2 from the atmosphere dissolves into ocean water is the water is cold, although as water warms up, CO2 can be released into the atmosphere. When carbon is absorbed it helps create carbonate that can form both animal parts and rocks. When oceans get warmer they release CO2 into the atmosphere that increases the greenhouse effect. This can further warm the water and cause more CO2 to be released into the atmosphere.

The last carbon sink is the lithosphere (or the crust and the upper mantle). This sink includes carbonate rocks and carbon in fossil fuels. Carbonate rocks from when the bones, teeth, and shells of fish accumulate on the ocean floor and are eventually turned into rocks. The carbon in these rocks can be released into the atmosphere again by the reaction of calcite with sulfuric acid. Carbon is also found in fossil fuels, these accumulate when carbon based life forms accumulate in water bodies and are buried. These can form coal, oil, and natural gas. When these fossil fuels are burned they enter into the atmosphere.

CUA 4 Question #18 - 2 | Student correctly identifies and describes 2 carbon sinks and discusses the processes that place and remove carbon in these sinks 4 pts | Student correctly identifies and describes 2 carbon sinks and discusses the processes that place and remove carbon in these sinks but miss several key points 3 pts | Student correctly identifies and describes 1 carbon sink and discusses the processes that place and remove carbon in this sink but not both 2 pts | Student correctly identifies and describes 1 carbon sink and discusses the processes that place and remove carbon in this sink but not both and misses several key points 1 pts | Insufficient 0 pt

19) Choose 2 ways humans put carbon into the atmosphere and suggest a way these sources could be curbed.

Answer: Carbon sources from humans are the burning of fossil fuels. We could curb this carbon from entering the atmosphere by burning fewer fossil fuels or sequestering the carbon before it enters the atmosphere. Human can also place more carbon into the atmosphere by burning forests or clear cutting forests. Humans can stop this carbon from getting into the atmosphere by leaving forest stands, replanting forests, and preventing large scale forest fires through land management. (The last way that CO2 could possible be put into the atmosphere by humans is through respiration. We can’t curb these, unless we tried to curb population growth.)

CUA 4 Question #19 - 2 | Student correctly identifies and describes 2 ways humans put carbon into the atmosphere and suggests ways these sources could be curbed 4 pts | Student correctly identifies and describes 2 ways humans put carbon into the atmosphere and suggests ways these sources could be curbed but miss several key points 3 pts | Student correctly identifies and describes 1 way humans put carbon into the atmosphere and suggest a way the source could be curbed but not both 2 pts | Student correctly identifies and describes 1 way humans put carbon into the atmosphere and suggest a way the source could be curbed but not both and misses several key points 1 pts | Insufficient 0 pt

20) Describe the surface distribution of the suns rays as it applies to latitude. How do the angles of sunlight affect wind production globally?

Answer: The Sun’s rays hit the surface directly at the equator and less directly at the poles. That means more sun is absorbed at the equator than at the poles. This is why the poles are so cold and the equator is so warm. This uneven heating of the Earth causes wind, areas that are heated cause the air to rise and this causes cold air to move into these locations, making global wind patterns.

CUA 4 Question #20 - 2 | Student describes the surface distribution of the suns rays and how the angles of sunlight affect wind production globally 4 pts | Student describes the surface distribution of the suns rays and how the angles of sunlight affect wind production globally but misses several key points 3 pts | Student describes the surface distribution of the suns rays or how the angles of sunlight affect wind production globally but not both 2 pts | Student describes the surface distribution of the suns rays or how the angles of sunlight affect wind production globally but not both and misses several key points 1 pts | Insufficient 0 pt