Module 1 Astronomy
Q1.9 From the reading "Philosophy and the Scientific Method," (a) describe how the author uses a barrel of apples analogy to explain the difference between "conceivably" true, "probably" true and "almost definitely" true. And (b) explain why no scientific theory is "absolutely" true (why can you never say with absolute certainty that all of the apples in the barrel are rotten, even though every one you have examined so far is rotten).
A. Barrel of apples that is never-ending Conceivably: pull one apple out of the barrel that is rotten and assume the entire barrel is rotten Probably: pull out one of the apples and assume that the rest are rotten because of bacteria (support with knowledge) Almost definitely: all of the apples are rotten because every single one pulled out has been rotten except for one B. A theory is never "absolutley" true because there is always a possibility that an apple may come out perfect, considering that the barrel is bottomless, no theory will never be 100% accurate.
Q1.10 From the reading "Philosophy and the Scientific Method," (a) explain the bias that led Tycho Brahe to disregard his carefully collected observational data and instead embrace the traditional view of his time of an Earth-centered Universe. (b) Explain the bias that helped Kepler solve the problem of predicting planetary motion from Tycho's data.
A. Because the belief that God would not waste so much space (Religion) B. Kepler was motivated by the belief that the Sun was the most appropriate object to be placed in the center of the universe because it was the material home of the manifestation of God
Q1.23* From the article "The Last Great Global Warming," how do we know the temperature of the water at the time these ancient sediment deposits occured?
Because of the mix of different forms of oxygen atoms in the skeletal remains.
Q1.52 From lecture, describe the three properties of a planet that are the most important factors in determining the planet's average temperature.
1. Distance from the sun 2. Reflectivity 3. Greenhouse effect
Q1.21* From the article "The Last Great Global Warming," after an initial buildup of Carbon Dioxide in the atmosphere caused perhaps by volcanic eruptions 56 million years ago, describe three other changes that occured (likely due to the initial Carbon buildup) to add even more heat-trapping gases to the atmosphere in a geologically short time (thousands of years).
1. Exposed forests 2. Peat lands to desiccation 3. Widespread wildfires
Q1.16 From the article "The Physical Science Behind Climate Change," describe two observations that demonstrate humans are responsible for the large increase in greenhouse gases in our atmosphere (as opposed to natural sources, like volcanos).
1. Geographic differences in concentrations reveal that sources occur predominantly over land in the more heavily populated Northern Hemisphere. 2. Analysis of isotopes, demonstrates that the majority of the increase in carbon dioxide comes from combustion of fossil fuels (coal, oil and natural gas). Methane and nitrous oxide increases derive from agricultural practices and the burning of fossil fuels.
Q1.19* From the article "The Physical Science Behind Climate Change," explain two patterns in our atmosphere that the authors consider to be a fingerprint of human influence, showing humans are caused the changes and not natural sources (like changes in solar activity).
1. Greater warming over land than ocean and of the surface of the sea than in deeper layers. 2. While the troposphere has warmed, the stratosphere has cooled.
Q1.29* From the Scientific American article "Meltdown," we learn that when "permanent" ice melts (either on the ocean or on land) due to warming, feedback effects from this can cause even more warming. Explain three ways the melting ice causes further warming in the Arctic.
1. Positive feedback, for example, warmer to melted ice to darker surface absorbs heat 2. Get rid of the isolation layer and let the ocean 3. Permafrost if you warm temperatures in the arctic
Q1.51 From lecture, what are two distinguishing characteristics of a scientific theory that make that theory likely to be valid for a long time, rather than a theory that is likely to be refuted or overturned relatively quickly?
1. Tends to be simple. Relies on one unifying principle. 2. Explains many things at once (makes predictions)
Q1.13 From Chapter 5.2, briefly describe the three main characteristics of blackbody radiation. Also, sketch a graph of intensity vs wavelength for a hot blackbody like the Sun and a cool blackbody like the Earth.
1. The curves of the blackbody show that at each temperature, our blackbody object emits radiation (photons) at all wavelengths (all colors) 2. An object at a higher temperature emits more power at all wavelengths than a cooler one. 3. The higher the temperature, the shorter the wavelength at which the maximum power is emitted. Shorter wavelength means higher frequency and energy.
Q1.55 From lecture, describe two examples of positive feedback effects in the Earth's climate.
1. Warmer - melt permafrost - more CO2 - circle back around 2. Warmer - melted ice - darker surface absorbs heat
Q1.56 From lecture, describe an example of a negative feedback effect in the Earth's climate.
1. Warmer - water vapor - more low, thick reflective clouds - cooler 2. Warmer air - thaw soil - more plants grow, soaking CO2 - cooler
Q1.31 From the Scientific American article "Meltdown," explain three ways in which increased moisture in the normally dry arctic air causes additional warming.
1. Water vapor is a greenhouse gas, in a dry Arctic winter atmosphere, a little more moisture can trap more heat. 2. When that moisture condenses into clouds, it releases latent heat, further warming the air. 3. More clouds trap more warmth below them, one more factor contributing to the Arctic meltdown.
Q1.30 From the Scientific American article "Meltdown," explain two ways in which "blocking high pressure systems" (more common in a warmer climate) tend to accelerate the melting of the Greenland ice sheet.
1.Heat and moisture from the south 2. Soot from wildfires this darkens ice and snow surfaces (lowering reflectivity), which then absorb more of the sun's energy, accelerating melt
Q1.17 From the article "The Physical Science Behind Climate Change," explain what are positive and negative "forcings" in climate science, and briefly describe two examples of each from the article.
A positive forcing includes warming. For example, solar energy and green house gases A negative forcing includes cooling. For example, aerosol and reflection or sunlight
Q1.28* From the Scientific American article "The Permafrost Prediction," if the permafrost in a given region thaws, some Carbon will be released from the soil, but it is also true that the same region will absorb more Carbon from the atmosphere. (a) Explain why, and (b) explain whether the net result is more Carbon added to the atmosphere or more absorbed from the atmosphere.
A. Because warming the ground with snow causes plants start growing and absorb the CO2 B. In the summer plants absorb more CO2 in fall and winter plants are dormant
Q1.7* From the reading "Philosophy and the Scientific Method," (a) explain one of the benefits of irrefutable ideas and also (b) explain the major weakness of a system of knowledge based upon irrefutable ideas.
A. Irrefutable ideas mean that they are invulnerable to disproof. Could be true, but cant be proved false B. When one irrefutable belief contradicts another, there is then no decisive way to make a choice between them
Q1.50* From lecture, what is (a) the major benefit and (b) the major drawback of a system of knowledge based upon scientific principles?
A. Major benefit: a way of thinking. Gives the ability to establish a consensus in a fact. B. Major drawback: often times the consensus is wrong. As time goes on and more advances are made, things believed before turn out to be wrong
Q1.27* From the Scientific American article "The Permafrost Prediction," if the permafrost in a given region thaws, (a) not all of its Carbon will be released and (b) what is released will be released slowly over decades or centuries. Explain each of these two claims (the first two of three key questions posed about Carbon release in the article).
A. The carbon is so inaccessible by microbes B. It is already in a semi decomposed state that microbes only further degrade slowly
Q1.12 From Chapter 5.2, (a) explain what is the definition of temperature (at the microscopic level), then (b) explain why hotter particles tend to emit light that has a shorter wavelength (or higher frequency) compared to cooler particles.
A. The temperature of something is a measure of the average motion energy of the particles that make it up B. In a hot material, the individual particles vibrate in place or move rapidly from collisions, so emitted waves are more energetic. Higher energy waves have a higher frequency. In cool material, the particles have low-energy atomic and molecular motions generating lower-energy waves.
Q1.43* From the decoding weather video, we find there is an imbalance in carbon. When we calculate how much carbon we are emitting, only about half of it shows up in the atmosphere, so we want to know where the rest of the carbon goes. Explain (a) how Dr. Greg Asner is attempting to answer this question (what instrument does he use and what does he measure), and (b) explain about what fraction of emitted carbon is being accounted for with Asner's measurements.
A. Trees. They breathe in carbon dioxide and they store up some of that CO2, causing that to reduce GHG. B. Trees are soaking up about ¼ of the extra CO2 emitted annually
Q1.44 From the decoding weather video, (a) explain what is the purpose of an Argo Float. Also, using these floats, (b) explain what Dr. Stephen Riser's team has discovered about the role of oceans in absorbing heat (by how much would our atmospheric temperature increase if they oceans weren't absorbing any heat, for example).
A. Underwater floats designed to explore parts of the Earth that have never been seen before. Specifically in the Southern ocean which has awful weather conditions for humans to explore. B. Deep cold water that has not been in contact for the atmosphere for many years, it soaks up heat like a sponge. The ocean has heated over ½ a degree fahrenheit. The atmosphere at the same time heats around 20 degrees.
Q1.38 From the "Flat Earth" video, Hossenfelder explains that many Flat Earthers believe you should not trust evidence collected by others. (a) Explain what is wrong with this argument and/or explain why accepting this argument would seriously cripple our way of life. (b) Explain how Hossenfelder recommends scientists address this philosophical problem.
A. You'd have to re-invent science. Science would never progress. B. Showcases the process that they did. Advertise the scientific process and its successes.
Q1.5 From the reading "Cargo Cult Science," in a couple of sentences, describe the story of Mr. Young's rat-running experiment (not every detail). Specifically, (a) explain why it is an "A-number-one" experiment compared to other experiments and (b) how Young could tell that the rats really did learn in response to his training.
A. Young eliminated all possible clues to prove that the rats were learning which door they had to enter when going down the corridor. He controlled every single variable. B. Since controlled every variable the experiment forced rats to learn.
Q1.22* From the article "The Last Great Global Warming," describe the two chemical changes that occured in the oceans due to the buildup of CO2 in the atmosphere.
Acidification the rising of CO2, temperature rises
Q1.45 From the decoding weather video, explain how Dr. Andrea Dutton is able to reconstruct the history of how high the sea level was a long time ago, when Earth's average temperature was similar to what it is today. Explain how she estimates sea level from long ago.
By drilling deep into a rock in Africa. Inside the cores she finds fossils of ancient coral, means that the entire landscape used to be an ocean. Coral looked like it needed sun to survive, therefore the sea level must have not been very high.
Q1.25 From the article "The Last Great Global Warming," explain what is different about the current era of global warming compared to the warming that occured at the beginning of the PETM.
Current global warming is much faster. CO2 concentrations are rising probably 10 times faster now than they did during the PETM
Q1.33 From the video "Patterns and Scientific Thinking," looking at sequence C, you may see three cards in a row with the number 9 and decide the rule is that all of the cards must have the same number. Looking further at the sequence, however, you would find that this rule is wrong. What is this process equivalent to in the scientific method?
Developing a hypothesis and testing it. More than one hypothesis proves a theory
Q1.37 From the "Flat Earth" video, although all evidence related to the shape of the Earth is gathered with one's senses, Flat Earthers typically ignore certain kinds of evidence that requires "decoding". As an example of decoding, Hossenfelder talks about buying a can of soup. Explain why it is rational to believe that the soup is safe to eat despite the fact that you cannot see, smell, touch or taste it while it is still enclosed in the can.
Draw on your knowledge People would be punished for selling something inedible in the supermarket
Q1.53 From lecture, describe how we use a comparison of Earth and Moon to prove that the greenhouse effect is real and warms that Earth by approximately 60 degrees Fahrenheit.
Earth and moon are the same distance from the Sun. The Albedo is about the same for the Earth and Moon. Greenhouse effect makes from Earth habitable GHG dont exist on the moon.
Q1.14 From Chapter 5.3, explain what property of atoms allows us to use a spectrum of light to identify which type of element (or molecule) is emitting or absorbing that light.
Every element has a unique fingerprint/signature that allows us to identify it.
Q1.48 From the short video "The Last Time the Globe Warmed," explain the fossil evidence tells us that temperatures in Arctic region were much higher during the PETM event 56 million years ago compared to today.
Fossils are of places with warm weather. Marine sediment samples show that there was a sudden spike in the amount of carbon dioxide. Based on the types of carbon found in these sediments, the gases likely came from plants that strived from warmer weather.
Q1.59 From lecture, fossil fuel advocates often refer to the "Medieval Warm Period" as a time when temperatures were comparable to current values despite the fact that CO2 levels in the atmosphere were much lower (about 260 ppm instead of the current value of 420 ppm). Explain what is the problem with this argument.
Global warming does not focus on an area of the world, it focuses on worldwide temperatures. This advocacy only refers to two local variations.
Q1.15 From Chapter 5.3, explain the cause of all of the dark lines in the solar spectrum seen in figure 5.11?
If the gas in a container consisted of two elements, then light passing through it was missing the colors (showing dark lines) for both of the elements. So it became clear that certain lines in the spectrum "go with" certain elements.
Q1.36 From the "Flat Earth" video, explain what the philosophy of empiricism is and how Flat Earthers use this philosophy to promote their theory.
If you want to understand nature you should only rely on information from your own senses
Q1.8 From the reading "Philosophy and the Scientific Method," an example is given of a letter written to a local paper criticizing the value of sex education in schools. Explain the difference in how the letter writer explains trends (such as a rise in sexually transmitted diseases) compared to how a scientist attempts to explain such trends (not every detail, just a sentence or two summarizing the scientific approach).
Letter: Parents don't teach sex-ed at home so it is up to teachers Scientist: What most people is the conclusion of an investigation is only the begining for scientists
Q1.46 From the decoding weather video, explain how we test the accuracy of models (describe the process of calibration) before using them to try to predict the future.
Line that shows average temp record is compared to one with actual temp record to check accuracy
Q1.42* From the decoding weather video, explain how Dr. Andrea Dutton is able to reconstruct the history of temperature in the Earth's atmosphere over the past 800,000 years (explain how is oxygen used in the process).
Looks for clues in seashells. Encoded in each layer is chemical information about the temperature of the water. As shells grow they incorporate oxygen from the sea water.
Q1.35* From the "Flat Earth" video, in one popular variant of the Flat Earth theory, our apparent weight is not caused by gravity but rather a constant upward acceleration of the flat disk of the Earth. Describe an observational fact that refutes this model.
Measure the strength of gravity in different parts of the earth. The gravitational acceleration is not the same everywhere.
Q1.34 From the video "Patterns and Scientific Thinking," it is possible to come up with more than one rule that could explain each sequence of cards. What problem does this lead to in the scientific method analogy?
More than one theory leads to inaccurate hypothesis
Q1.1 From the reading "Cargo Cult Science," give two examples of practices scientists should follow in order to have scientific integrity, to make it more likely that their work will make a positive contribution to the overall body of human knowledge (instead of being refuted or disproven a short time later).
Record everything you observe even if it doesn't agree with your problem, give all the tools and information you used so that people can replicate it
Q1.2 From the reading "Cargo Cult Science," explain the difference between science and advertising (or advocacy).
Science says that scientists will always tell you every bit of truth. Advertising you only receive the recordings or facts that will help you, leave out certain things. For example, a recipe shows you exactly how to make the cookies, not the trial and error.
Q1.4 From the reading "Cargo Cult Science," describe the story of the history of subsequent research that followed the Millikan oil drop experiment, and explain why, in Feynman's opinion, it is such an embarrassing story for scientists.
Scientists assume that their measurements are correct based on the closeness to Milikan's value and did not bother to double check them. Feynman believed that scientists should always double check their answers and post every bit of their findings
Q1.18* From the article "The Physical Science Behind Climate Change," explain the evidence found in computer models of the climate that indicate that natural climate forcings are not sufficient to explain the rise in average temperature since the mid-20th century and that anthropogenic (human-caused) factors must be largely responsible.
Set of climate data. If the anthropogenic (manmade) factor is left out of the model, it cannot predict correctly. It sets the clock back 50 years to test the model.
Q1.32 From the Scientific American article "Meltdown," explain why increases in Arctic temperatures impact weather in lower latitudes (like the continental United States) via the changing jet stream.
The Arctic's lower atmosphere can affect winds in the jet stream. Northward peaks and southward valleys in the bending jet stream generate the high- and lowpressure centers. The bends control our weather in the Northern Hemisphere. Large bends in the jet stream tend to progress more slowly from west to east, causing the weather systems they create to hang around longer.
Q1.57 From lecture, fossil fuel advocates often refer to the "Greening Earth" hypothesis. Explain what this hypothesis is and why it would "solve" the global warming problem.
The Green Earth hypothesis CO2 levels are going up leading to plants growing faster, greening the Earth. Plants will soak up all the CO2
Q1.54* From lecture, (related to Q1.11 and Q1.12) use a graph of blackbody radiation to help explain why gases that block infrared light tend to warm the Earth due to the nature of the incoming and outgoing light (the blackbody curves).
The Sun is much hotter than the Earth. Average energy of light is much greater. Earth eradiates all of its life in the infrared. GHG block transmission of light. 10% of incoming light is blocked (cooling) 50% of outgoing Earthshine is blocked (heating). What happens to your car on a sunny day.
Q1.24 From the article "The Last Great Global Warming," what makes it so difficult to study the carbonate-rich skeletal remains of sea life during the PETM era?
The baking sediments, released large doses of two strong greenhouse gases, carbon dioxide and methane. Judging by the enormous volume of the eruptions, the volcanoes probably accounted for an initial buildup of greenhouse gases enough to raise global temperature by a couple of degrees. But most analyses, suggest it took something more to propel the PETM to its hottest point.
Q1.26 From the Scientific American article "The Permafrost Prediction," climate scientists are trying to learn what will happen as the permafrost thaws by artifically warming small areas of the permafrost using fences. Explain how the fences warm the soil, enabling scientists to study the warming effects.
The fence acts as isolation. Warmer temperature = permafrost thaws = more carbon released in the air. Warmer temperatures = ice melts = darker surface = absorbs more heat
Q1.3* From the reading "Cargo Cult Science," how would you explain to the "cargo cult" people of the South Seas why the planes don't land? Answer in a simple, direct way: what are they doing wrong, or why is what they are doing not working? Hint: think about why the planes REALLY landed and what has changed.
The war is over. The packages are no longer needed, nothing they do is going to make them back. There are no more people stationed on the island.
Q1.58 From lecture, explain why the "Greening Earth" hypothesis is not valid.
There is a carbon cycle associated with plants. When trees and die they decompose, releasing all the CO2 back to the atmosphere
Q1.39 From the decoding weather video, describe the evidence found in New York City that tells us it was much colder there about 20,000 years ago.
There was a glacier over Manhattan, this can be seen by the rock that could not be moved by another force than a glacier
Q1.20 From the article "The Physical Science Behind Climate Change," we expect quite a bit of sea level rise from melting glaciers in Antarctica and Greenland. Besides that source, what will be the primary cause of sea level rise during the 21st century?
Thermal expansion of the water in the ocean.
Q1.60 From lecture, fossil fuel advocates explain that during the period from about 1940-1970, the overall average temperature of the Earth cooled, despite the fact that CO2 levels were rising, and similar during the period from 2005-2013. Explain why this argument is invalid.
They are only looking at factors that support their case. Advocacy is not science.
Q1.11 From Chapter 5.1, explain why the behavior of light led scientists to believe that the space between the planets, stars and galaxies was not empty but instead filled with a thin air-like substance known as aether.
They believed that light waves could not travel through empty space so they made up aether, with no evidence to back it, just so that light waves could have something to travel through
Q1.41 From the decoding weather video, explain why carbon dioxide levels in Dave Keeling's experiment go down in the Spring and up in the Fall.
Trees breathe in the CO2, drawing it out of the atmosphere throughout the Spring. In the fall when the leaves die and decompose the CO2 goes back into the air.
Q1.40 From the decoding weather video, describe John Tyndall's experiment that showed Carbon Dioxide gas blocks the transmission of heat, thus enabling it to trap heat in the Earth's atmosphere. How exactly did Tyndall measure this effect?
Used a sensor to measure the temperature difference between two sources of heat. On one side was a tube that he could fill with different gases. Air, Nitrogen, Oxygen. When he tests the two gases the needle on the vault meter didn't budge. Nitrogen and Oxygen have no affect on heat. He tried Carbon Dioxide and realized that the radiated heat doesn't make it through.
Q1.6 From the reading "Philosophy and the Scientific Method," explain what is the distinguishing difference between scientific and non-scientific ideas.
What separates scientific theories from nonscientific ones is how vulnerable the ideas are allowed to be
Q1.47 From the short video "Understanding Natural Climate Cycles," why does the amount of Carbon Dioxide in our atmosphere seem to track the Earth's long-term orbital cycles that cause warming and cooling?
When the planet warms a bit, that enhances ocean mixing, the oceans lose their fizz to the atmosphere. More CO2 in the atmosphere. More heat in the planet.
Q1.49 From the short video "The Last Time the Globe Warmed," explain why core samples from the deep sea prior to the PETM warming typically lighter in color and those during the PETM warming are much darker.
Where forams are abundant, the chalky fossils of their shells turned the ocean bed white. When the oceans became more acidic the sediments turn dark because the forams disappear.
