1. Briefly describe each of the three properties of a planet that determine its temperature. Use these to help explain how we know that the greenhouse effect is real and warms the Earth by about 60 degrees Fahrenheit.
-distance to the sun, reflectivity, greenhouse effect. The moon is similar to earth in distance and reflectivity but the earth has a stronger atmosphere that traps more gasses warming it 60* more.
2. Explain how we use Carbon isotope evidence to support the idea that the increase in Carbon Dioxide in Earth's atmosphere over the past 200 years is largely due to human activity as opposed to a natural process or cycle.
The Carbon isotope shows an increase in carbon-12 and no change in carbon-14. This is because humans throw off the balance when we burn fossil fuels, and take part in deforestation. Poor agricultural practices like these throw off the natural cycle because there is no carbon-14 being released when humans participate in such acts.------------------------------------------------------------------------------------------------------------------------------------
3. From Chapter 4, section 4.3 of your textbook, briefly explain the difference between thermal energy and temperature. Explain why can you safely put your arm in a 400 degree oven (for a brief time) but you cannot do the same for a pot of (212 degree) boiling water.
-thermal energy measures the total kinetic energy of all the randomly moving particles in a substance. -temperature measures the average kinetic energy of the particles -The reason for that is density, the density of the water is much higher than the oven, meaning water has far more molecules in the same amount of space
4. From Chapter 4, section 4.3, explain how the Kelvin temperature scale is related to Fahrenheit and Celsius. What is absolute zero? One advantage of the Kelvin scale is that it never uses negative temperatures. Explain why this makes sense using the definition of temperature from question 1.
-Kelvin does not measure negative temperature, it starts at the coldest possible temp, 0 (absolute zero). -This makes sense because temperature is an average kinetic energy of the particles.
5. From Chapter 5, section 5.1 of your textbook, briefly describe the four different ways that light can interact with matter.
-Emission: a lightbulb emits visible light, the energy comes from electrical potential energy supplied by the lightbulb. -absorption: when you place your hand near an incandescent light, your hand absorbs the light and the energy warms your hand. -transmission: some forms of matter, such as glass or air, transmit light, which means it allows it to pass through. -reflection and scattering: light can bounce off a matter. reflection is what we call when the light is bouncing off in the same general direction. Scattering is when the bouncing is more random.
6. From Chapter 5, section 5.2, briefly explain the difference between a particle and a wave (light has the properties of both). Also, know the simple definitions of wavelength, frequency and photon.
-A particle is individual atom or molecule. A wave is a pattern revealed by its interaction with particles. Moves energy not particles. -Wavelength: distance between the peak to peak. -Frequency: the number of peaks passing any point after a few seconds.. -Photon: a peices light energy(particle that travels in wave)
7. From Chapter 5, section 5.2, explain how infrared light compares to visible light in the electromagnetic spectrum. Specifically, is it longer or shorter wavelength? Higher or lower frequency? Higher or lower energy?
-Infrared light has slightly longer wavelengths than visible light. Infrared has lower frequency and has lower energy than visible light.
8. From section 5.4, what are the two laws of thermal radiation? Explain how we can use a thermal radiation spectrum for an object to determine the temperature of the object.
-Law 1: each square meter of a hotter objects surface emits more light at all wavelengths. -Law 2: hotter objects emit photons with a higher average energy (hotter objects emit shorter wavelengths) Red-Blue The Thermal radiation spectrum depends on only temp measure by looking at objects color
9. Explain the difference between weather and climate. Why is local temperature variation not really important in terms of global warming?
-Weather: is the day-day forecast of a particular location over a short period of time -Climate is how global temperature behaves over long periods of time. Local temperature isn't important because it only gives information about a particular area and it doesn't give information for a long period of time.
10. Describe how written records can be used to estimate the temperature from hundreds of years ago, even before the invention of the thermometer. ---------------------------------------------------------------------------------------------------
Written records were used to record when plants grew and leaves fell to measure variation in temperature.
11. To go back further, 1000 or more years, scientists look in places like Lake Tuborg or an old forest. Briefly describe what scientists look for when they look at ice layers in a frozen lake and tree rings in a forest. Do thicker layers/tree rings mean warmer (wetter) climate or cooler (drier) climate? Explain why for each case.
When looking at ice layers' scientist look for sediment in the lake. When looking at tree rings in forest, scientist look at the thickness of tree rings. More sediment in the ice layers means more melting which means higher temperatures, and thicker rings means more rain which also means warmer temperatures.---------------------FIX_---------------
12. What is the Keeling curve? Why does it go up and down during the Spring and Fall?
The Keeling Curve is a graph that plots the change in the concentration of CO2 in the earth's atmosphere. The levels decrease in the spring as new plant growth takes carbon dioxide out of the atmosphere and rises again in the fall as plants and leaves die off.
13. Explain how we can use ice core measurements to estimate the Carbon Dioxide content of the atmosphere hundreds of thousands of years ago. How do current atmospheric conditions compare to those measured during the past 400,000 years?
We use ice cores to measure the composition of air bubbles, amount of CO2 in air, in the ice cores. Atmospheric conditions are slightly warmer than 400,000 years ago.
14. According to the fossil fuel industry, increases in Carbon Dioxide will act like "plant food" and accelerate the growth of forests and other plant life. Explain how this hypothesis is being tested and whether the test confirms the hypothesis.
This is being tested by bathing the trees in extra CO2 which causes the plants to grow rapidly but it doesn't help the CO2 abundance because once the trees die the extra carbon is released therefor increasing CO2 abundance.
15. Will this "greening hypothesis" enable the problem to essentially solve itself by taking all the excess Carbon out of the atmosphere? Explain.
No it will not because we lose a majority of this CO2 to the atmosphere before it is absorbed by the plant life.
16. In computer models, name and explain one example of a positive feedback effect and a negative feedback effect. Why do the computer models have such a wide range of possible predictions about future temperatures?
Look at model. Positive Amplifies original cause/Adds to it. Negative- cancels out original change. scientists don't really know how clouds form and there are so many different variables.
17. From the reading "Cargo Cult Science", explain "why the planes don't land" to a typical islander who might ask, in a few sentences.
The planes were originally landing because of the war over the land. The planes were bringing materials to the soldiers. Now that the war is over the planes won't return.
18. From the reading "Cargo Cult Science", briefly summarize the story of Mr. Young's experiment and why those who ignore his work cannot really trust their conclusions.
he ran rats through a maze and found out all of the possible variables that affected the rats ability to find the food. He didn't learn anything new about the rats but just a new way to conduct the experiment more accurately. people who ignore his work cannot be trusted because his experiment is the right way to perform an experiment. One must account for every possible variable.
19. From the reading "Cargo Cult Science", briefly explain the story of the Millikan oil drop experiment and the subsequent history. Explain why this was such an embarrassing episode for scientists.
measured the charge on an electron by using falling oil drops. Not knowing that the previous experiment was conducted wrong, later scientist were comparing their data to skewed data and tried to adjust their results to fit Millikan's. Scientist were ashamed because several of them did the same thing over and over again.
20. One potential consequence of global warming will be a relatively fast rise in sea levels as a result of melting ice (mainly in West Antarctica, since it is currently on land) and one other mechanism, described in the first few paragraphs of the following scientific discussion summary:http://www.faqs.org/faqs/sea-level-faq/. Read these paragraphs and summarize in a sentence or two another mechanism besides melting ice that may cause sea levels to rise as the Earth warms up.
The warming of the temperature of the ocean. Colder water is more dense than warmer water, and therefore takes up less space. Warmer water would therefore occupy more space and cause sea levels to rise.
21. From section 10.2, list the three other major factors besides changes in the greenhouse effect that can cause climate change. Explain how and why a change in axial tilt of the Earth would change the climate to be warmer or cooler.
-solar brightening -changes in axis tilt -changes in reflectivity -The tilt can change because of gravitational pull from moons, other planets, or the sun. An extended summer prevents ice buildup which decreases reflectivity and warms the planet
22. From section 10.2, briefly explain three things that can change the Earth's reflectivity, aside from melting ice or freezing water.
-microscopic dust particles called aerosols, released in volcanic eruptions, can increase reflectivity -human activity like smog can act like volcanic dust and increase reflective Roads and cities decrease reflective -deforestation also increases reflective because it removes sunlight absorbing plants.
23. From section 10.6, describe the carbon cycle, which is the collection of sources that add carbon dioxide to the atmosphere and the collection of sinks that take away carbon dioxide from the atmosphere.
atmospheric co2 dissolves in rainwater creating a mild acid. This acid erodes rocks and rivers carry the sediment to the ocean. In the ocean calcium from the broken down minerals combines with dissolved co2 and falls to the ocean floor making carbonate rocks like limestone. Over millions of years plate tectonics bring the limestone to subduction zones. When they go deeper into the mantle some of the carbonate rocks melt and release their co2, and is released back into the atmosphere through volcanoes.
24. From section 10.6, describe the negative feedback loops that have kept Earth's climate from becoming too warm or too cold in the past. Why are these feedback loops likely not sufficient to stabilize Earth's climate if we triple the Carbon abundance in our atmosphere over the course of the next 100 years?
When it becomes too cool there will be less precipitation leading to rainwater dissolving less greenhouse gasses, heating up the earth. When it becomes too warm there will be more precipitation, more co2 from atmosphere dissolves in rainwater, co2 in the atmosphere decreases and the earth will begin to cool. If we continue to increase the co2 in the atmosphere, the co2 cycle operates much too slowly to absorb these emissions on human time scales.
25. From section 10.6, explain the evidence offered by the textbook's authors (related to computer models) that suggest the recent warming of the Earth has been caused by human activity rather than some natural cycle.
climate models that ignore human activity fail to match the observed rise in global temperatures. In contrast models that do include human production of greenhouse gasses match the observed temperature trend quite well. Comparisons between models clearly indicate that global warming results from human activity.
26. Explain how nuclear fission generates energy (where, exactly, does the energy come from in the reaction). Also, explain briefly how nuclear power plants convert this energy into electricity.
the energy comes from the loss of mass during the chemical reaction. The energy from this reaction heats up water and the steam from that causes turbines to move, and that energy is converted to electrical energy.
27. What difficulty prevents most countries from obtaining nuclear weapons? The following three questions are from the August 2007 Scientific American article, "The Physical Science behind Climate Change". Below are instructions on how to access Scientific American articles online using the TCU library's website.
(1) Go to www.lib.tcu.edu. (2) Under the green "Search" button are five choices. Select "Library Catalog," 2nd on the list. (3) Just above the green "Search" button is a selection menu that says "words anywhere." Change this to "Journal name begins with...", (4) Type "scientific american" in the search box and hit the green "Search" button. (5) On the next page, click on the first entry. This takes you to a list of records. Click on the link that reads "Full text available to the TCU community from Nature Journals Online: 1993 to present". It should be the third link. (6) You may have to type in your TCU username and password at this point if you are accessing the library from off-campus. (7) Type your subject of interest or article name in the search box. For example, "nuclear power" or "global warming" or "renewable energy". You can then view the text or download a pdf file containing the entire article with diagrams and pictures.
28. What is radiative forcing? What does "positive" radiative forcing and "negative" radiative forcing mean? Give an example of each in climate science.
the change in global energy balance compared to pre-industrial times. A positive forcing induces warming; a negative forcing induces cooling. Positive forcings pulling the earth to a warmer climate and negative ones pulling it to a cooler state
29. What evidence in our atmosphere suggests that the recent warming of the past century is not due to changes in solar activity?
A second pattern of change is that while the troposphere (the lower region of the atmosphere) has warmed, the stratosphere, just above it, has cooled. If solar changes provided dominant forcing, warming would be expected in both atmospheric layers
30. Even if we were to stop emitting Carbon altogether today, the climate would continue to warm for at least another couple of decades, if not longer. Explain why.
This inertia in the climate results from a combination of factors. They include the heat capacity of the world's oceans and the millennial timescales needed for the circulation to mix heat and carbon dioxide throughout the deep ocean and thereby come into equilibrium with the new conditions
31. From the reading "Philosophy and the Scientific Method," (below the syllabus links on the main class web page) what is the primary difference between a scientific and a non-scientific belief? What is the major weakness of using irrefutable beliefs as a basis for a system of knowledge? I strongly recommend you check your answer on this one with me.
What separates scientific beliefs from nonscientific ones is how vulnerable the ideas are allowed to be. The major weakness of using irrefutable beliefs as a basis for a system of knowledge is that you cannot prove that it is true, but also cannot prove that it is false.
32. In the reading "Philosophy and the Scientific Method," a "letter to the editor" is discussed, in which the letter writer confuses correlation and causation. Explain the difference between the letter writer's point of view and the scientific point of view.
correlation does not prove causation. Just because one thing happened and caused another does not mean that it is a result of the changed variable. The writer if jumping to a conclusion when proper scientific method must be applied first to make a scientific conclusion.
33. From the reading "Philosophy and the Scientific Method," use the barrel of apples analogy to help explain the difference between "probably true" and "almost definitely true, beyond any reasonable doubt."
say there is a barrel of 100 apples. If you take out the first apple and its rotten, that doesn't mean the remaining 99 are rotten as well. Even if you take out 99 apples and all 99 were rotten, that doesn't mean the last one will be too, but chances are very high and we can make an educated guess that it will be.
34. If the Kyoto protocol were enacted, how would that change projected atmospheric concentrations of carbon dioxide over the next 100 years, compared to "business as usual" projections?
There would only be a +10% change. Normal projection is 700 ppm (+100%). Kyoto projection is 660 ppm (+90%).
35. Briefly explain why climate scientists weren't satisfied with the Kyoto treaty and also why politicians were also not satisfied (summarize one of the reasons given in each case).
Politicians believe there is no net gain. Scientists weren't satisfied because there would only be a 10% change.
36. What are three types of renewable power sources mentioned in the film? Briefly explain two major drawbacks that are associated with renewable energy sources in general.
Solar power, wind energy, and biomass are all renewable power sources. Renewable energy resources aren't always readily available, and storing electricity from renewable resources is expensive.
NA. Why can't Venus store Carbon from its atmosphere the way Earth can?
Because Venus has no ocean like earth does. Weather is the main way to store carbon, and without it, you only have sources of carbon and no sink.
NA. Explain what causes the "breathing" of the Earth's atmosphere, causing the CO2 abundance to go up and down during the year.
When spring comes to the North, where most trees are, co2 is absorbed by the trees and the levels go down. When fall comes and the trees shed their leaves, co2 levels go back up. When plants and flowers bloom and grow they absorb, but when they die they don't absorb as much.
How do we know that the CO2 abundance in the atmosphere today is much higher than any time during the last million years or so? How do we measure the CO2 abundance from such a long time ago?
We know because we drill down in ice caps to find and test trapped air bubbles. We analyze the trapped air from different time periods and can compare it to air today.
Explain why predictions about the climate are more reliable than predictions about the weather.
Weather is chaotic, a microscopic change can cause the weather to change, whereas climate is predictable. It is the global average with simple inputs.
Explain why the melting ice caps cause more warming that magnifies the warming effect of increasing CO2 (a positive feedback loop).
Ice reflects sunlight but the darker colored water absorbs it. The more water there is, the more sunlight that gets absorbed. (positive feedback cycle)
Although solar energy was a proven technology over 100 years ago, it was not used widely as an energy source. Why not?
Because the cost of coal was so cheap, and no one really knew the true cost of burning coal. Also, during ww1 countries couldn't wait around for a new way to power vehicles, so they mainly ignored solar.
Explain an example of a positive feedback loop and a negative feedback loop involving water vapor in the Earth's climate.
positive feedback loop: earth warms, more h2o vapor in the atmosphere, high thin clouds trap heat, warming earth. Negative feedback loop: earth warms, more water vapor in atmosphere, low thick clouds reflect incoming energy, earth cools
Use the laws of blackbody radiation and a graph of incoming vs outgoing radiation to explain how the greenhouse effect warms the Earth. Specifically, address the question, "If greenhouse gases block both incoming and outgoing infrared light, why don't those effects cancel, leading to no net warming?"
Gases block a larger fraction of the outgoing energy because it is in a different spectrum than incoming energy. Greenhouse gases block some 10% of incoming light, which cools us off, but it blocks about 50% of outgoing light which warms us up.
Why is thermal radiation referred to as "blackbody radiation"?
a blackbody is an opaque object that emits thermal radiation. A perfect blackbody is one that absorbs all incoming light and does not reflect any. Therefore it only emits thermal radiation.
Some argue that global warming is not occurring because during a specific period of time (say, the last 20 years), the average temperature of the Earth hasn't significantly changed. Explain why this is an example of advocacy instead of scientific reasoning.
Advocacy because they are looking at small segments of time instead of the obvious gradual temperature increase. It is a dishonest way of getting support for fossil fuels. If you are going to make a case, you have to back it up.
The Kyoto Protocols were an attempt to negotiate internationally agreed-upon limits on CO2 emissions. Explain how the CO2 levels in the year 2100 would change from "business as usual" if the Kyoto Protocols were followed by all nations (use a graph, show both cases). Also, what happened with the Kyoto Protocols politically in the United States?
If the kyoto protocol is followed, the year 2100 would be 660 ppm as opposed to 700 ppm. This is a minuscule change. This protocol was voted against 95 to 0.
What prevents most countries from having nuclear reactors or weapons?
The enrichment process of uranium is restricted by nuclear powerful countries that limit the special metal used for the centrifuge that can withstand such high temperatures. Without enriching uranium, uranium is useless.
Briefly explain three major drawbacks associated with nuclear (fission) energy.
If something goes wrong/ it blows up, the surrounding area becomes unliveable and poisonous for thousands of years. Second, we have no way of disposing of the mildly radioactive material, and it is hard to keep out of the wrong hands. Third, like other fossil fuels there is a limit on it, and at this rate we will run out in 100 years.
Explain how water can be used to store energy generated by windmills for later use when the wind isn't blowing.
Excess electricity is used to pump water from a low reservoir to a higher one. When there is no wind, the high reservoir can dump water that will then turn turbines as it flows back to the lower reservoir.
Explain how underground caverns can store and release energy generated by windmills. Also, explain one technical hurdle in this process and how utilities are trying to overcome it.
Up on the surface, powerful electric pumps inject air at high pressure into the cavern when electricity supply exceeds the demand. When the grid is running short, some of that compressed air is let out, blasting through turbines and spinning them. One practical hurdle is that air heats up when it is compressed and gets cold when it is allowed to expand. That means some of the energy that goes into compression is lost as waste heat.
From the last part of the article, how does an electrolyzer convert electricity into stored energy? How does a fuel cell release this stored energy for use? What currently limits this kind of process from widespread use in homes?
it splits water into hydrogen and oxygen by running an electric current through it. The hydrogen can later be consumed in a fuel cell to generate electricity. What limits the use of this is that to light a building or provide energy for a car, this device would cost 10,000s of dollars. also, hydrogen in gas form is explosive so it has to be compressed or made into a liquid.
In addition to an increase in CO2 due to volcanic eruptions, describe two other processes that contributed methane and CO2 to the atmosphere to accelerate the warming process during the PETM era.
When pangea split apart it exposed to the surface a large amount of carbon rich sediments, coal, and oil which released co2 and methane. The second, stirring of the oceans moved warmth to the cold seabed destabilizing large amounts of frozen methane and hydrate. As the hydrates thawed, methane bubbles came up to the surface and released even more carbon into the atmosphere. Or, because of the warming there were droughts and following the droughts came wild fires which release co2 into the atmosphere as living material was burned.
Explain the two chemical changes that occurred in the oceans due to the PETM warming. What were these changes, and how did rising CO2 levels cause them?
The increase in co2 in the atmosphere was absorbed by the oceans, so much that it created high levels of carbonic acid. As the deep sea temperatures rose, oxygen levels decreased and 30-50% of the species in the deep went extinct
Explain how we use deep-sea sediment cores to indicate temperatures long ago. Also, explain why these sediment cores are the most degraded and difficult to interpret during the period when the most warming took place?
sediment is laid down on the ocean floor layer by layer, and each layer contains sediment and skeletal remains. By testing the different forms of isotopes in the skeletal remains it reveals the temperature of the ocean at that time. They are hard to interpret because during the PETM, ocean acidification dissolved away much of the carbonate in the sediments in exactly the layers where the most extreme conditions of the PETM era should have been represented.
Explain what the authors eventually discovered by the PETM that was different from previous conclusions. Also, how does the CO2 increase during the PETM compare to today's CO2 increase, and what do the authors therefore conclude about comparisons between the PETM and the modern era changes in ecology?
They concluded that during the PETM period the increase was not nearly as severe as scientists had previously thought. In comparison to modern times we are releasing co2 at a breakneck speed. In the past few decades we have increased co2 by 30%
Explain how the use of breeder reactors or fuel reprocessing may help overcome the problem of the limited global supply of Uranium for nuclear fission reactors. Also, explain the major drawback of this solution, different from the previous drawbacks about nuclear power discussed.
The breeder reactors allow for more energy when the fuel rods are being used up. The major drawback is proliferation; the spread and disposal of the nuclear waste is potentially dangerous and can lead to new weapons being developed.
Explain why nuclear fusion reactions require extremely high temperatures. Also, why must the fusing material be contained somehow and a high density maintained?
High temperature is required to make the molecules move fast enough for them to come close enough to fuse together. You need confinement because you want a lot of collisions because only a small percent of the collisions of the hydrogen are successful
Why is it difficult to contain fusion reactions? Explain inertial and magnetic confinement.
because of the high temperature required. -Inertial confinement: shooting a hydrogen pellet from all directions in order to heat up the hydrogen enough for fusion to occur. -magnetic confinement: is an approach to generating fusion power that uses magnetic fields to confine the hot fusion fuel in the form of plasma. Fusion reactions combine light atomic nuclei such as hydrogen to form heavier ones such as helium. In order to overcome the electrostatic repulsion between them, the nuclei must have a temperature of several tens of millions of degrees.
What are Deuterium and Tritium? Explain how nuclear fusion (D-T fusion) generates dangerous waste products.
deuterium is a form of hydrogen that has one extra neutron and tritium is also a form of hydrogen that has two extra neutrons. Fusion generates nuclear waste because when anything is bombarded with extra neutrons it becomes radioactive and unstable.
Briefly describe two major drawbacks currently about nuclear fusion power that prevent it from being implemented widely, then explain for each how we hope to overcome these problems.
Nuclear fusion has a Q level below one, meaning more energy is spent performing the process than the process produces. It also releases a free neutron which then creates radioactive products. We are hoping to overcome these problems in the future.
Three renewable sources of energy we discussed are biomass, solar and wind. Explain how "biomass" works as a way to generate energy. Briefly describe three potential drawbacks shared by all three of these energy sources.
Biomass is a carbon neutral process of burning organic materials (crops) to produce energy. The drawbacks are that they are episodic (not always available), they lack portability, and they have low energy density, meaning they take up a lot of land.
One alternative source of power that may help account for current energy production and future growth is nuclear energy. What are two major long-term drawbacks associated with nuclear energy?
Nuclear energy is only available for so long and it will eventually become expensive because of the high demand for energy.
What are breeder reactors? How might breeder reactors overcome one of these drawbacks, and what is a major problem associated with breeder reactors?
Complex technology, nuclear proliferation - speed of nuclear materials that can be converted into weapons.
What was the political fate of the Kyoto treaty in the United States?
This was political suicide because it would cause the economy to go down.