chem cycle 7 quiz savvas questions

Study the curve for the stages of glaciation and then study the curve showing the eccentricity. Describe how well the two curves correspond to one another. Explain what this suggests about the possible cause of the recent cycle of ice ages.

The eccentricity curve is a more general version of the glaciation curve, which is slightly offset of it. This suggests that eccentricity is a major part in the temperature and the cycle of ice ages.The correlation indicates that fluctuations in Earth's orbit and eccentricity significantly influence glaciation patterns, supporting the Milankovitch cycles theory.

Suppose that you are a farmer living in Texas. Would you prefer an El Nino or La Nina phase of Pacific Ocean oscillation? Use the maps to construct and explanation to support your response.

If I were a farmer living in Texas, I would likely prefer an El Niño phase of the Pacific Ocean oscillation. During an El Niño event, the Pacific Ocean's warmer waters cause shifts in atmospheric circulation, often bringing increased rainfall to Texas. This additional moisture can help alleviate drought conditions, improve soil moisture, and support crop growth.

Use the equations for the area of a circle (A=pir^2) and a sphere (SA = 4pir^2) to explain why the insolation, or exposure to the sun’s rays, is 1361+-0.5 at Earth’s orbit but is about 340.3+-0.125 for any point on Earth’s surface.

The difference in insolation at Earth's orbit (1361 W/m²) and the average insolation received at any point on Earth's surface (about 340.3 W/m²) can be explained using the formulas for the area of a circle and the surface area of a sphere.

1. Insolation at Earth's Orbit (Solar Constant):
   The Sun emits energy in all directions, and at Earth's distance, this energy spreads out over an imaginary sphere with a radius equal to Earth's orbital radius. The intensity of solar radiation at this distance, called the solar constant, is given as approximately 1361 W/m². This value represents the amount of energy received per square meter on a flat, perpendicular surface outside Earth's atmosphere.

2. Distribution Over Earth's Surface:
   While the solar constant applies to a perpendicular surface in space, Earth is a rotating sphere. The total energy intercepted by Earth is based on its cross-sectional area, which is given by the area of a circle:

   A=πr²

   However, this energy is then spread over Earth's entire surface, which is a sphere with surface area:

   SA=4πr²

   Because the total energy is distributed over four times the cross-sectional area, the average energy received per unit area on Earth’s surface is: 340.3W/m²

3. Conclusion:
   The key reason for the reduction in insolation is that Earth is a sphere, and sunlight is distributed over its entire surface rather than just a single cross-sectional area. This division by four accounts for the fact that not all parts of Earth receive sunlight equally at all times due to rotation and axial tilt, leading to an average insolation of about 340.3 W/m² across the planet.

Examine the map of the Ring of Fire. Construct an explanation for why most large-scale volcanic eruptions occur in and around the area highlighted on the map.

 Lots of subduction and tectonic activity occur in the Ring of Fire. The melting of rock and formation of magma leads to magma rising to the surface in the form of volcanoes.

Examine the two maps. The current shape of the Persian Gulf has changed little in the past 6000 years. Calculate how fast the Persian Gulf coastline moved landward between 15,000 and 6,000 years ago.

distance travelled = 90 m

yrs = 15000-6000= 9000 yrs

90m/9000yrs = 0.01 m/yr

In the years 536 and 540 there were very large volcanic eruptions (in Iceland and Central America). What evidence do you see in this graph?

The graph shows a significant drop in temperature, which is strong evidence for volcanic eruptions, because of the formation of sulfates which shield sunlight from the Earth.

How do volcanic eruptions affect climate in the short-term?

Volcanic eruptions primarily affect climate in the short-term by releasing large amounts of ash and sulfur dioxide gas into the atmosphere, which can form tiny reflective particles called aerosols that block sunlight, causing a temporary cooling effect on the planet; essentially creating a "volcanic winter" by shading incoming solar radiation.

 How do changes in solar radiation affect intermediate-term climate?

Changes in solar radiation, primarily through fluctuations in the Sun's overall brightness, can affect intermediate-term climate by causing slight variations in global temperature, although the impact is considered relatively small compared to human-caused greenhouse gas emissions; these changes can influence regional weather patterns, particularly when significant solar minima occur, potentially leading to cooler temperatures and altered precipitation patterns.

What are the effects of short-term ocean circulation changes like ENSO on the atmosphere?

Short-term ocean circulation changes like ENSO (El Niño-Southern Oscillation) significantly affect the atmosphere by disrupting global atmospheric circulation patterns, leading to altered weather patterns including changes in precipitation and temperature across various regions of the world, particularly impacting mid-latitude jet streams and causing variations in rainfall and temperature in regions far from the tropical Pacific Ocean where the ENSO event originates.

What is currently happening in Earth’s long-term, intermediate-term, and short-term climate, and for how long has it been happening?

Earth's long-term climate is experiencing a significant warming trend, with average global temperatures steadily increasing over the past century, primarily due to human-caused greenhouse gas emissions; this warming is happening at a rate not seen in the past 10,000 years; in the intermediate term, this warming is causing changes like earlier spring seasons and altered precipitation patterns, while short-term climate events like El Niño and La Niña cycles may be becoming more extreme due to the overall warming trend.

Liquid water has existed on Earth’s surface for at least 4 billion years, even as the sun’s energy output has continued to increase. The total area of continents (now 39% of Earth’s surface) may have grown in size over Earth’s history. Think about what you know about the albedos of land and water. Does an increase in land area explain why Earth’s surface hasn’t heated to a point that the ocean has boiled away? Why or why not?

No, an increase in land area does not fully explain why Earth’s surface hasn’t overheated. Land has a higher albedo than water, meaning it reflects more sunlight and absorbs less heat, which could help cool the planet. However, other factors, like greenhouse gases (CO₂ and water vapor), cloud cover, and the carbon cycle, have a bigger impact on regulating Earth’s temperature over billions of years.

 Calculate the mean time between the starts of cold glacial periods over the past 500 million years.

There have been about five major glacial periods in the last 500 million years. A glacial period starts about every 100 million years.

Explain why it would make sense that the amount of water vapor in Earth’s atmosphere would decrease as Earth’s surface cooled. Where did that water go?

When Earth’s surface cooled, the amount of water vapor in the atmosphere decreased because cooler air holds less moisture. The water condensed into liquid, falling as rain and eventually collecting in oceans, lakes, and ice caps.

Observe the correlation between the patterns of the two curves. Land plants evolved about 470 million years ago and expanded across the continents, developing into forests. Explain the carbon dioxide during this time.

Around 470 million years ago, land plants spread and absorbed CO₂ through photosynthesis, reducing greenhouse gases in the atmosphere. This likely led to a decrease in temperatures, contributing to cooling and possibly even a glacial period.

The Deccan Traps, large flood basalts covering much of western India, formed around 66 million years ago. What effects did their formation likely have on Earth’s atmosphere. Explain.

The Deccan Traps released large amounts of CO₂ and sulfur dioxide, leading to both global warming (from CO₂) and acid rain (from sulfuric acid). These changes likely affected climate and ecosystems, and may have played a role in the mass extinction around 66 million years ago.

If the velocities of tectonic plates were to significantly decrease, would it have a cooling effect or warming effect on Earth’s climate? Explain.

 If tectonic plate movement slowed down, volcanic activity would decrease, reducing CO₂ emissions. With less CO₂ in the atmosphere, the greenhouse effect would weaken, leading to cooler global temperatures over time.

The United States has the largest deposits of coal in the world. Coal forms from fossilized swamp vegetation. Use the map to explain why most of these coal deposits likely formed between 350 and 250 million years ago.

Most U.S. coal deposits formed 350–250 million years ago when the region was near the equator and covered in warm, swampy forests. Over time, dead plant material was buried, compressed, and turned into coal, creating the large deposits found today.

 How does the presence of ice sheets impact Earth’s climate through feedback mechanisms?

Ice sheets have a high albedo, meaning they reflect a large amount of sunlight. This helps cool the planet further in a positive feedback loop—as temperatures drop, more ice forms, reflecting even more sunlight and causing additional cooling. Conversely, when ice melts, darker land and ocean surfaces absorb more heat, leading to further warming.

How did volcanic activity contribute to past mass extinctions?

Large volcanic eruptions, like those that formed the Siberian Traps (~252 million years ago) and the Deccan Traps (~66 million years ago), released vast amounts of CO₂ and sulfur dioxide. CO₂ caused long-term global warming, while sulfur dioxide led to acid rain and temporary global cooling due to sunlight-blocking aerosols. These climate shifts disrupted ecosystems, contributing to mass extinctions.

How does the carbonate-silicate cycle help regulate Earth’s long-term climate?

The carbonate-silicate cycle is a natural process that regulates CO₂ levels over millions of years. When CO₂ dissolves in rainwater, it forms carbonic acid, which reacts with rocks, removing CO₂ from the atmosphere. Over time, this carbon is stored in ocean sediments as carbonate minerals. Volcanic eruptions then release CO₂ back into the air, balancing the cycle and helping stabilize Earth’s climate.

Explain why croplands have higher albedos than forests.

Forest albedo tends to be lower than cropland albedo due to the darkness of tree bark and lack of snow cover during the winter.

Jet airplanes create long, straight clouds called contrails. How could you change the schedules of airplane flights to reduce their warming impact?

To reduce the warming impact of contrails, airlines could adjust flight schedules by avoiding nighttime and early morning flights when contrails trap more heat. They could also alter flight altitudes to avoid humid, cold air where contrails form, reroute flights away from contrail-prone regions, and cluster flights to limit overall contrail coverage. These changes would help minimize contrails' contribution to global warming while maintaining travel efficiency.

You have probably had the experience of leaving a cold bubbly soda out in the open and finding that it had gone flat when it warmed up (bubbles are CO2). Explain how the phenomenon can be used to model the ocean’s ability to store CO2.

When soda heats up, it loses its fizziness, which is a result of CO2 escaping the soda water. This can be used to model the ocean’s ability to store CO2 because the ocean heating up allows CO2 to escape the water and return back into the atmosphere.

Describe what humans can do in the future using the biosphere to reduce CO2 levels in the atmosphere.

Humans can use the biosphere to reduce CO₂ levels by enhancing natural carbon sinks. This includes planting more trees and restoring forests, as trees absorb CO₂ through photosynthesis. Expanding wetlands and seagrass meadows can also help, as these ecosystems store large amounts of carbon. Sustainable farming practices, such as cover cropping and agroforestry, can increase soil carbon storage. Additionally, protecting biodiversity and reducing deforestation will help maintain ecosystems that naturally regulate CO₂ levels.

Notice how the amount of methane measured in the atmosphere at Barrow, Alaska changes over time. Construct an explanation for why the trend may continue upward in the future.

 The trend will most likely continue upwards due to rapid warming in the Arctic. Rapid warming in the Arctic allows methane, a powerful greenhouse gas, to escape the permafrost of the tundras, driving more warming.

From what you know about differences between the surfaces of Venus, Earth, and Mars, construct an explanation for why Earth’s atmosphere contains such a smaller percentage of CO2 than both of its neighbors, Venus and Mars.

 Only Earth has liquid water on its surface, which acts as a carbon sink. Theremore, it will have less CO2 in the atmosphere as compared to Venus and Mars.

Use the information provided by the 30^oC curve in the graph to estimate the percent increase in Earth’s emitted radiation if the surface temperature of the planet increased from 15^oC to 30^oC. 

30 C = 303 K, 15 C = 288 K

(303 K - 288 K)/288K = 2%

The graph shows the extent of sea ice over the past 1400 years. How much did the area of ice change prior to 1800? How much is the loss of sea ice area since 1800?

Prior to 1800, the area of sea ice fluctuated at around 10^7 km^2. After 1800, the area of ice dramatically dropped to 8 x 10^6 km^2

If the area exposed in the image of the glacier in the Purcell Mountains occurred over a period of 25 years, estimate the years until the rest of the glacier melts.

 I estimate that the glacier will most likely melt within the next 75 years. I think this because a quarter has melted in the span of 25 years. Assuming that temperatures will remain unaccelerated by human pollution, then according to the rate of ¼ glacier every 25 years, the glacier should fully melt in 75 years.

 Describe a reinforcing or counterbalancing factor you think can cause droughts in California. Explain your reasoning.

A reinforcing factor that can cause droughts in California is a positive feedback loop from reduced soil moisture. When a drought begins, less rainfall leads to drier soil, which reduces the amount of moisture that can evaporate into the air. Since evaporation helps form clouds and precipitation, lower moisture levels can lead to even less rainfall, reinforcing the drought. This cycle makes it harder for the region to recover.

A counterbalancing factor could be atmospheric river events, which bring large amounts of moisture from the Pacific Ocean to California. These intense storms can temporarily relieve drought conditions by providing heavy rainfall and snowpack in the Sierra Nevada, which serves as a long-term water source. However, their impact depends on frequency and intensity—too few atmospheric rivers may not be enough to break a prolonged drought.

Why more than twice as much energy reaching surface is long-wave infrared radiation and not short-wave visible radiation, despite the fact that sunlight is mostly visible radiation?

Although sunlight is mostly visible radiation, more than twice as much energy reaching Earth's surface is long-wave infrared radiation due to the greenhouse effect. The Earth absorbs short-wave visible radiation from the Sun and then re-emits it as longer-wavelength infrared radiation. This infrared radiation is trapped by greenhouse gases in the atmosphere, causing it to be re-radiated back toward the Earth's surface, increasing the overall amount of long-wave infrared energy. This process results in a higher concentration of long-wave infrared radiation compared to the incoming visible sunlight.

Why is it the most efficient way to fly in the troposphere (10.5km high) for planes?

The air is thin enough to minimize drag but dense enough to provide lift for flight.

A narrow region of high evaporation in the Atlantic Ocean, east of North America, coincides with the Gulf Stream. A similar region exists in the Pacific Ocean, south of Japan. It corresponds to the Kuroshio Current. Explain why you think water is evaporating more rapidly from these currents.

Water is likely evaporating more rapidly from the Gulf Stream and the Kuroshio Current due to the warm temperatures of these currents. Both the Gulf Stream and the Kuroshio Current carry warm water from the tropics toward higher latitudes, which increases the temperature of the surface water. Warmer water has a higher evaporation rate because the molecules have more energy to break free from the surface into the atmosphere. Additionally, these currents are often associated with strong winds, which help to remove the evaporated water vapor from the surface, allowing more evaporation to occur. The combination of warm temperatures and wind leads to higher evaporation rates in these regions.

Air volume increases when pressure decreases. Use this relationship to explain why warm air at the equator rises up through the less dense air above it.

Warm air at the equator rises through the less dense air above it because warm air expands, causing its volume to increase and its density to decrease. As the air warms up, the molecules move faster and spread out, making the air lighter than the cooler, denser air around it. This difference in density creates an upward force, causing the warm air to rise. As the air moves upward, it encounters lower pressure at higher altitudes, which allows it to expand further, reinforcing its upward movement. This process is a key component of convection, driving the upward flow of warm air at the equator.

Clouds form over low-pressure region where air is rising, while at high-pressure region, sunlight hits the ground as cold air is sinking. Explain why his pattern might change and reverse over time.

The pattern of cloud formation and air movement can change and reverse over time due to shifts in weather systems and seasonal changes. At low-pressure regions, air rises, cools, and condenses to form clouds. In high-pressure regions, air sinks, warming up and preventing cloud formation. However, as the Earth’s atmosphere is dynamic, factors like changes in temperature, wind patterns, or the Earth's rotation (Coriolis effect) can cause these systems to shift. For example, during seasonal changes, the temperature differences between the equator and poles may alter the positioning of low and high-pressure systems. El Niño and La Niña events, for instance, can also change atmospheric circulation patterns, reversing where low and high-pressure systems form. These changes can cause the location of rising and sinking air to shift, reversing the typical cloud formation and weather patterns.

Use the model of atmospheric circulation to explain why most of the world’s deserts are roughly 30^o north, 30^o south, or at the poles.

The air coming from the equator dries out before reaching 30 degrees north and 30 degrees south, which causes deserts to be formed.

Examine the graph of relative humidity compared to temperature for a city over a 3-day period. The temperature reaches a peak at about 3 pm on Day 3. Estimate how much water vapor. 

40% of water vapor is in the air.

In the diagram, notice that freezing rain and sleet fall as liquid rain through the cold air mass before freezing. Use what you know about the energy of changes of state to explain.

Freezing rain and sleet form when liquid rain falls through a cold air mass, but the temperature of the air is not cold enough to freeze the rain immediately. As the rain falls, it passes through a layer of cold air, which causes it to freeze. In the case of freezing rain, the rain remains liquid until it reaches the ground, where it freezes upon contact. In sleet, the rain partially freezes into small pellets before hitting the ground. This happens because as the rain cools, it loses energy, causing a change of state from liquid to solid. The freezing process releases energy (latent heat), which may cause some of the rain to melt again before freezing further.

Where will it be cool a day later?

It will be cold in the Southeast.

Where do tropical storms occur?

In the equator.

Two factors that affect stability of California’s climate.

factor 1 - burning of fossil fuels destabilizes climate by destroying ozone layer and increasing temperature

factor 2 - photosynthesis holds carbon dioxide which stabilizes the climate by reducing fossil fuel output.

 Develop model to show how factor destabilizes climate. 

How is residence time related to size of reservoir?

The larger the reservoir, the more time it takes to heat, and therefore, water will stay in the reservoir longer.

Which process requires energy from sun?

Snow melt runoff, Evaporation, Evapotranspiration

Describe difference between residence time for carbon in coal and in other parts of carbon cycle.

Carbon stays in coal for a very long time, however, all other aspects happen relatively quickly like combustion, respiration, and decay.

What pattern do you observe when comparing surface carbon reservoirs and rocks in Earth’s crust?

The residence time of carbon in Earth’s crust is significantly greater than all of the surface carbon reservoirs combined.

Complete the diagram

 Is melting of a glacier an example of a tipping point?

The melting of a glacier reduces albedo and causing the global temperature to warm, leading to a new equilibrium.