Earth and Space Science (Grades 9–12)

Subtest 2 Sample Items

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Question 1

1.

The question contains a Hertzsprung-Russell diagram, commonly referred to as an H-R diagram. The Hertzsprung-Russell diagram is a scatter graph of stars that are plotted on the graph based on their spectral class, absolute magnitude, luminosity, and surface temperature. Absolute magnitude is plotted on the Y axis to the left of the diagram, luminosity is plotted on the Y axis to the right of the diagram, spectral class is plotted on the X axis at the top of the graph, and surface temperature is plotted on the X axis at the bottom of the graph.
The scales for Hertzsprung-Russell diagram are as follows:
Absolute Magnitude: From positive 20 at the bottom of the scale to negative 10 at the top of the scale.
Luminosity: From 0.000001 at the bottom of the scale to 1,000,000 at the top of the scale. The sun has a luminosity value of 1.0 on the luminosity scale.
Spectral Class: From the letter "O", which is located to the far left on the spectral class scale to the letter "M" located to the farthest right of the scale.
Surface Temperature: From a high temperature of 40,000 K, which is located to the far left on the temperature scale, to 2,500 K, which is located to the farthest right of the scale.
A loosely clustered line of stars, known as main-sequence stars, crosses the graph from near the upper left-hand corner to the lower right-hand corner. The sun is a main sequence star located in this clustered line of stars about half way between the top and bottom of the graph and approximately two-thirds from the left side of the graph to the right side of the graph. Given its position on the diagram, the sun has the following properties at this stage in its evolution:
Absolute Magnitude: +4.8
Luminosity: 1.0
Spectral Class: G
Surface Temperature: 5,778 K
The responses to the question are all Hertzsprung-Russell diagrams showing four possible evolutionary sequences for the sun after it leaves the main sequence section of the diagram.
The question is as follows:

In the Hertzsprung-Russell diagram shown above, the sun is in the main sequence phase of its life cycle. Which of the following diagrams best represents a plot of the various phases that a low-mass star, such as the sun, will go through after it leaves the main sequence?

1. First, the sun is shown moving to the lower left (below the main sequence), then almost straight up to the upper left, then back down to the lower left, and finally at the end of its life cycle, it is shown in the far lower right-hand corner, where its surface temperature is shown to be just above 1,200 K.
2. First, the sun is shown moving part of the way toward the upper right (above the main sequence), then a small distance back toward the lower left (still above the main sequence), then up toward the top of the diagram almost to the upper right-hand corner, and then straight across to the far left of the diagram, and finally, at the end of its life cycle, it is shown dropping down toward the lower left where its surface temperature is shown to be approximately 20,000 K.
3. First, the sun is shown moving most of the way toward the upper left hand corner of the diagram, then across the very top of the diagram to the upper right-hand corner of the diagram, and finally dropping directly down to the lower right-hand corner where its surface temperature is shown to be approximately 1,500 K.
4. First, the sun is shown dropping down approximately two-thirds of the way toward the lower left (below the main sequence), then upward toward the right (still below the main sequence), then back down toward the lower left-hand corner (although not all the way to the corner), then it goes straight up three-quarters of the way to the top of the diagram, then it moves about three-quarters of the way across the top of the diagram from left to right, and finally drops (at about a forty-five degree angle to the right of the perpendicular) to the very lower right-hand corner of the diagram where the temperature is shown to be approximately 1,100 K.

Answer to question 1

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0008). Hertzsprung-Russell diagrams represent the absolute brightness and luminosity versus the spectral class and temperature of a star at different evolutionary stages. A low-mass star, such as the sun, remains in the main sequence stage for most of its life with hydrogen fusion occurring at its core. Once the hydrogen in the core is depleted, the star begins to contract. As gravitational energy is converted to heat energy, the star expands and grows brighter. In this red giant stage, the star burns helium for fuel. When the helium runs out, and as happens in a medium-sized star, the star does not have enough carbon or oxygen to burn for nuclear fuel and as a result begins to collapse. As it collapses, the star ejects its outer layers of gas and dust, forming a planetary nebula. The star finishes collapsing into a white dwarf, which has a high surface temperature, but its luminosity is greatly diminished because it has no major source of nuclear energy. Correct Response: B. (Objective 0008). Hertzsprung-Russell diagrams represent the absolute brightness and luminosity versus the spectral class and temperature of a star at different evolutionary stages. A low-mass star, such as the sun, remains in the main sequence stage for most of its life with hydrogen fusion occurring at its core. Once the hydrogen in the core is depleted, the star begins to contract. As gravitational energy is converted to heat energy, the star expands and grows brighter. In this red giant stage, the star burns helium for fuel. When the helium runs out, and as happens in a medium-sized star, the star does not have enough carbon or oxygen to burn for nuclear fuel and as a result begins to collapse. As it collapses, the star ejects its outer layers of gas and dust, forming a planetary nebula. The star finishes collapsing into a white dwarf, which has a high surface temperature, but its luminosity is greatly diminished because it has no major source of nuclear energy.

Question 2

2. Use the diagram below to answer the question that follows.

The Hertzsprung-Russell diagram groups stars by their absolute magnitude and surface temperature in degrees Kelvin. Absolute magnitude is depicted on the Y axis with the bbsolute magnitude increasing from the origin upwards. The X axis depicts the surface temperature of stars in degrees Kelvin beginning at forty thousand degrees at the origin and decreasing to two thousand five hundred degrees. The X axis also groups stars with the letters O, B, A, F, G, K, and M from left to right. The mainline stars are depicted as a downward sloping curve running from O to M with decreasing temperaure and absolute magnitude. Stars that are off the main sequence are labeled. Betelgeuse has a high absolute magnitude, but a low surface temperature. It is in the upper right of the diagram. Sirius B has a high surface temperature, but a low absolute magnitude. It is in the lower left portion of the diagram.

For the main sequence stars along the diagonal line of the Hertzsprung-Russell diagram, the absolute magnitude, or brightness, of the star is roughly correlated with the star's surface temperature. However, for stars in the upper right of the diagram, such as Betelgeuse, this is not true. Betelgeuse is very bright, but has a low surface temperature. Similarly, stars in the lower left of the diagram, such as Sirius B, are very dim, but have a high surface temperature. Which of the following best explains these anomalies?

1. Stars in the upper right of the diagram are very close to our solar system, while those in the lower left of the diagram are very far away.
2. Stars in the upper right of the diagram are at the end of their life cycle, while those in the lower left of the diagram are just beginning their life cycle
3. Stars in the upper right of the diagram emit a higher proportion of their radiation as visible light, while those in the lower left of the diagram emit a higher proportion of their radiation as radio waves.
4. Stars in the upper right of the diagram are very massive, while those in the lower left of the diagram are very small.

Answer to question 2

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: D. (Objective 0008) In the diagram, the stars in the upper right of the diagram are red giants, which are often main sequence stars that have entered the last stages of their life cycle. These stars are relatively cool, but are very large and so have a high absolute magnitude. The stars in the lower left of the diagram are white dwarfs, which are often main sequence stars at the very end of their life cycle. These stars have a very high surface temperature, which is apparent from their white color, but are extremely small stars and so have a low absolute magnitude. Correct Response: D. (Objective 0008) In the diagram, the stars in the upper right of the diagram are red giants, which are often main sequence stars that have entered the last stages of their life cycle. These stars are relatively cool, but are very large and so have a high absolute magnitude. The stars in the lower left of the diagram are white dwarfs, which are often main sequence stars at the very end of their life cycle. These stars have a very high surface temperature, which is apparent from their white color, but are extremely small stars and so have a low absolute magnitude.

Question 3

3. Use the table below to answer the question that follows.

Which line in the table best documents the events at the end of the life cycle of most stars that are ten or more times more massive than the sun?

1. Line 1
2. Line 2
3. Line 3
4. Line 4

Answer to question 3

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: A. (Objective 0008) Very massive stars are hot enough to ignite elements heavier than helium. Shells of oxygen, neon, magnesium and silicon form with each element providing fuel for the next set of reactions. However, when silicon "burns" during nuclear fusion into iron the reaction stops because iron cannot burn and release energy. As the core shrinks, pressure and temperature rise and protons and electrons in the iron fuse, forming a ball of neutrons. In less than a second, the core collapses and the outer layers fall inward, raising temperature and pressure even higher until a supernova occurs. The remains of the core survive as a ball of neutrons—a neutron star—or an even more compressed black hole. Correct Response: A. (Objective 0008) Very massive stars are hot enough to ignite elements heavier than helium. Shells of oxygen, neon, magnesium and silicon form with each element providing fuel for the next set of reactions. However, when silicon "burns" during nuclear fusion into iron the reaction stops because iron cannot burn and release energy. As the core shrinks, pressure and temperature rise and protons and electrons in the iron fuse, forming a ball of neutrons. In less than a second, the core collapses and the outer layers fall inward, raising temperature and pressure even higher until a supernova occurs. The remains of the core survive as a ball of neutrons—a neutron star—or an even more compressed black hole.

Question 4

4. While observing the Milky Way galaxy with an optical telescope, an astronomer notes a dark region with only a small number of stars and determines that it is a dark nebula. Dark nebulae represent which of the following astronomical phenomena?

1. a cloud of interstellar dust that blocks out the view of the background stars behind it
2. a gap in the distribution of stars caused by the destruction of neighboring stars by a massive black hole
3. a large cluster of dark matter that blocks out the view of the background stars behind it
4. a cloud of dark energy that absorbs the visible light emitted from the stars in its immediate vicinity

Answer to question 4

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: A. (Objective 0008) The Milky Way consists of billions of stars, as well as the interstellar gas and dust dispersed throughout the galaxy. The interstellar gas and dust provide the source material for the birth of new stars. The dust scatters the light from the stars, obscuring our ability to see very far into the Milky Way galaxy. Some of this gas and dust collects in large clouds called dark nebulae. These may scatter the light from stars behind them in our line of sight so effectively that they look like large areas of empty space with a few stars showing up in the foreground. Correct Response: A. (Objective 0008) The Milky Way consists of billions of stars, as well as the interstellar gas and dust dispersed throughout the galaxy. The interstellar gas and dust provide the source material for the birth of new stars. The dust scatters the light from the stars, obscuring our ability to see very far into the Milky Way galaxy. Some of this gas and dust collects in large clouds called dark nebulae. These may scatter the light from stars behind them in our line of sight so effectively that they look like large areas of empty space with a few stars showing up in the foreground.

Question 5

5. The presence of vast amounts of dark energy in the universe was originally hypothesized to explain which of the following observations?

1. The mass of an object distorts and curves the space around it, and the more massive the object, the more the surrounding space is curved.
2. Younger galaxies are receding away from each other at greater speeds than older galaxies are receding away from each other.
3. Cosmic background radiation is distributed uniformly in all directions throughout the universe.
4. The distribution of galaxies in the universe is uneven, with some regions having large clusters of galaxies and other regions having very few galaxies.

Answer to question 5

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0008) Precise measurement of the rate at which galaxies are separating from one another shows that older galaxies near the edge of the universe are receding from each other at lower speeds than younger galaxies. This indicates that the rate of expansion of the universe has increased as the universe has aged. To explain these observations, scientists postulated the existence of a force that would not only overcome the force of gravity tending to draw the galaxies to together, but also actually increase the rate at which they separated. This repulsive force was named dark energy since it cannot be directly observed but must be inferred from its effects on the matter that makes up the universe. Correct Response: B. (Objective 0008) Precise measurement of the rate at which galaxies are separating from one another shows that older galaxies near the edge of the universe are receding from each other at lower speeds than younger galaxies. This indicates that the rate of expansion of the universe has increased as the universe has aged. To explain these observations, scientists postulated the existence of a force that would not only overcome the force of gravity tending to draw the galaxies to together, but also actually increase the rate at which they separated. This repulsive force was named dark energy since it cannot be directly observed but must be inferred from its effects on the matter that makes up the universe.

Question 6

6. Astronomers use a variety of instruments, including both optical and radio telescopes, to obtain information about astronomical objects. Which of the following advantages do radio telescopes provide compared to making observations using an optical telescope?

1. Radio telescopes use multiple small reflectors to collect signals while optical telescopes can only use one uninterrupted reflector.
2. Radio telescopes utilize long-wavelength energy in the electromagnetic spectrum and therefore can collect data 24 hours per day under most weather conditions as opposed to optical telescopes that are most effective at night.
3. Optical telescopes must be used on remote mountaintops to reduce light interference from human-made sources, while radio telescopes are not susceptible to human-made interference.
4. Radio telescopes have higher resolving power when compared to optical telescopes with a reflector diameter of an equivalent size.

Answer to question 6

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0008) Whereas optical telescopes utilize the visible part of the electromagnetic spectrum, radio telescopes access radio waves, which have longer wavelengths. Therefore, radio telescopes can function 24 hours per day because radio waves can be received regardless of the presence of sunlight or cloud cover. This is in contrast with optical telescopes, which are most effectively used at night, due to interference from the brightness of the sun. Correct Response: B. (Objective 0008) Whereas optical telescopes utilize the visible part of the electromagnetic spectrum, radio telescopes access radio waves, which have longer wavelengths. Therefore, radio telescopes can function 24 hours per day because radio waves can be received regardless of the presence of sunlight or cloud cover. This is in contrast with optical telescopes, which are most effectively used at night, due to interference from the brightness of the sun.

Question 7

7. When astronomers measure the velocity of orbiting stars in many galaxies, the velocities of stars farther from the galactic center do not have decreased velocities, as is predicted by Kepler's third law. Astronomers hypothesize that the difference between observed and predicted velocities of the orbiting stars in a galaxy is the result of which of the following factors affecting gravitational forces?

1. large stars within globular clusters that border the galaxy
2. high-density globular clusters in regions of space near the galaxy
3. dark matter in a halo surrounding the visible galaxy
4. interstellar nebula enclosing the galaxy with dust and ionized gases

Answer to question 7

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: C. (Objective 0008) The velocities of the stars orbiting in a galaxy do not match what the laws of gravity and Kepler's third law predict; however, these predictions were based on the luminous matter that was observed. The presence of dark matter surrounding the observed galaxy would explain this discrepancy. Dark matter cannot be observed, but its existence can be inferred by observing its effect on other objects. Calculations indicate the dark matter exists as a halo that envelops the visible matter of galactic disks and extends well beyond the edge of a galaxy's visible matter. Correct Response: C. (Objective 0008) The velocities of the stars orbiting in a galaxy do not match what the laws of gravity and Kepler's third law predict; however, these predictions were based on the luminous matter that was observed. The presence of dark matter surrounding the observed galaxy would explain this discrepancy. Dark matter cannot be observed, but its existence can be inferred by observing its effect on other objects. Calculations indicate the dark matter exists as a halo that envelops the visible matter of galactic disks and extends well beyond the edge of a galaxy's visible matter.

Question 8

8.

The question contains a diagram of a planet's elliptical orbit around a star. The star is located approximately two-thirds of the way to the left of the center of the planet's elliptical orbital path. Two separate sections on either side of the ellipse are defined by triangular shapes that have vertices at the star and widen as they meet the edge of the ellipse. Since the ellipse is curved the side of the triangular shapes created by the ellipse is curved. The triangular shape to the left of the star encompasses an area labeled "area X ". The angle of the vertex of this triangular shape is approximately 45 degrees. The triangular shape to the right of the star is labeled "area Y ". The angle of the vertex of this triangular shape is approximately 10 degrees. The triangle that encompasses area Y is much longer and thinner than the triangle that encompasses area X , however beneath the diagram is the mathematical statement that area X = area Y.
The section of the ellipse that makes up the curved side of the triangular area labeled "area X " is designated "distance X", while the section of the ellipse that makes up the curved side of the triangular area labeled "area Y " is designated "distance Y". Because of the difference in the shapes of the two triangular areas, distance Y is approximately one-third the length of distance X. The question is as follows:

According to Kepler's second law, which of the following statements concerning the planet's orbit of the star shown above must be true?

1. The time it takes the planet to travel through distance X will be greater than the time it takes the planet to travel through distance Y.
2. The velocity of the planet will be greater as it travels through distance X than it will be as it travels through distance Y.
3. The time it takes the planet to travel through distance X will be less than the time it takes the planet to travel through distance Y.
4. The velocity of the planet will be less as it travels through distance X than it will be as it travels through distance Y.

Answer to question 8

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0009) According to Kepler's second law of planetary motion, a line between the sun and a given planet sweeps equal areas in equal time intervals. This is shown in the diagram as area X being equal to area Y, meaning that the planet moves distance X in the same amount of time it takes to move distance Y as it orbits the sun. Since the areas in both the X and Y regions of the planet's orbit are equal, the distance traveled along region X must be greater than that along Y. In order for the longer distance to be covered in the same amount of time, the velocity of the planet when it is closer to the sun must be faster than the velocity of the planet as it moves along distance Y, at the point farthest from the sun. Correct Response: B. (Objective 0009) According to Kepler's second law of planetary motion, a line between the sun and a given planet sweeps equal areas in equal time intervals. This is shown in the diagram as area X being equal to area Y, meaning that the planet moves distance X in the same amount of time it takes to move distance Y as it orbits the sun. Since the areas in both the X and Y regions of the planet's orbit are equal, the distance traveled along region X must be greater than that along Y. In order for the longer distance to be covered in the same amount of time, the velocity of the planet when it is closer to the sun must be faster than the velocity of the planet as it moves along distance Y, at the point farthest from the sun.

Question 9

9. Which of the following provides the best evidence that the moon was largely molten early in its formation?

1. the layered structure of the crust and mantle with lighter minerals at the top and heavier minerals at the bottom
2. the lack of any volatile gases in an atmosphere or trapped within the first few meters of the moon's crust
3. the large basaltic maria representing cooled lava flows that are older than the surrounding highlands
4. the presence of numerous rills across the surface of the maria representing cracks that formed as the moon cooled and shrank

Answer to question 9

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: A. (Objective 0009) The impact event that formed the moon produced material that was very hot. As this material reaccreted it formed a moon that was largely molten. As magma cools, some elements crystallize at higher temperatures than others. The elements crystallizing earliest as the molten moon cooled would sink inward, while later crystallizing and lighter elements would float on top. This would yield a layered structure of the crust and mantle. The moon's crust and mantle exhibit such a layered structure, with anorthosite at the top of the crust underlain by plagioclase feldspar. Olivine and pyroxine are located deeper, forming the moon's mantle. Correct Response: A. (Objective 0009) The impact event that formed the moon produced material that was very hot. As this material reaccreted it formed a moon that was largely molten. As magma cools, some elements crystallize at higher temperatures than others. The elements crystallizing earliest as the molten moon cooled would sink inward, while later crystallizing and lighter elements would float on top. This would yield a layered structure of the crust and mantle. The moon's crust and mantle exhibit such a layered structure, with anorthosite at the top of the crust underlain by plagioclase feldspar. Olivine and pyroxine are located deeper, forming the moon's mantle.

Question 10

10. Which of the following best explains why Earth is better able to support life than its neighboring planets, Mars and Venus?

1. Earth's large moon stabilizes Earth's rotation, which prevents eccentricities in Earth's orbit that could lead to extreme variation in yearly temperatures.
2. Earth's large iron core and rapid rotation create a strong magnetic field that prevents damaging ionizing radiation from reaching the surface.
3. Earth's location relative to the sun results in temperatures that allow water to remain in its liquid state over much of the planet's surface.
4. Earth's large size creates a strong gravitational field that allows the retention of an atmosphere that is rich in heavier gases such as oxygen and nitrogen.

Answer to question 10

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: C. (Objective 0009) Liquid water is considered to be essential for the appearance of life as we know it. Because of its nearness to the sun and the greenhouse effect of its heavy cloud cover, surface temperatures on Venus are too high to allow water to remain as a liquid. Most water on Mars is permanently frozen due to its distance from the sun and its thin atmosphere. Only on Earth are temperatures moderate enough that water remains as a liquid over most of the planet. Correct Response: C. (Objective 0009) Liquid water is considered to be essential for the appearance of life as we know it. Because of its nearness to the sun and the greenhouse effect of its heavy cloud cover, surface temperatures on Venus are too high to allow water to remain as a liquid. Most water on Mars is permanently frozen due to its distance from the sun and its thin atmosphere. Only on Earth are temperatures moderate enough that water remains as a liquid over most of the planet.

Question 11

11. Use the table below to answer the question that follows.

Which line in the table best describes the long-term tidal effects of gravitational interaction between the moon and Earth?

1. Line 1
2. Line 2
3. Line 3
4. Line 4

Answer to question 11

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: A. (Objective 0009) The action of the moon's gravity on Earth creates tidal bulges on either side of Earth. As Earth spins, friction between the ocean and the solid Earth below drags the tidal bulge ahead of the line of gravity that connects the center of the moon and the center of Earth. The moon's gravity pulls back on the bulge, creating drag that slows the rotation of Earth. Following Newton's third law, Earth's gravity exerts a corresponding effect on the moon, pulling it ahead in its orbit and accelerating its orbital speed. In effect, angular momentum is transferred from Earth to the moon. That acceleration of the moon's orbital speed causes it to recede from Earth by about 4 centimeters per year, steadily increasing the distance between the two. Correct Response: A. (Objective 0009) The action of the moon's gravity on Earth creates tidal bulges on either side of Earth. As Earth spins, friction between the ocean and the solid Earth below drags the tidal bulge ahead of the line of gravity that connects the center of the moon and the center of Earth. The moon's gravity pulls back on the bulge, creating drag that slows the rotation of Earth. Following Newton's third law, Earth's gravity exerts a corresponding effect on the moon, pulling it ahead in its orbit and accelerating its orbital speed. In effect, angular momentum is transferred from Earth to the moon. That acceleration of the moon's orbital speed causes it to recede from Earth by about 4 centimeters per year, steadily increasing the distance between the two.

Question 12

12. Use the photograph below to answer the question that follows.

Which of the following best describes how the tail of the comet shown in the photograph is produced?

1. Small pieces of ice and rock break off from the comet's head and their inertia causes them to be left behind, forming a long tail as the comet travels through space.
2. Solar radiation striking the comet's head creates negatively charged particles that are repulsed from positively charged particles remaining in the head, forming a long tail.
3. Lighter particles in the comet's head are less attracted by the gravitational force of the sun than heavier particles and stream out behind the head as a long tail.
4. Microscopic dust grains are pushed out from the comet's head by solar radiation pressure and, along with gases pushed outward by the solar wind, form a long tail.

Answer to question 12

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: D. (Objective 0009) Comets are composed primarily of ice and dust. Solar radiation striking microscopic dust grains exerts a tiny force that is enough to push them out from the head and into a tail. At the same time, solar radiation vaporizes volatiles in the comet's head and these gases are pushed into a tail by the solar wind. Sometimes a comet will exhibit two tails, one composed primarily of dust and the other composed of ionized gas. Correct Response: D. (Objective 0009) Comets are composed primarily of ice and dust. Solar radiation striking microscopic dust grains exerts a tiny force that is enough to push them out from the head and into a tail. At the same time, solar radiation vaporizes volatiles in the comet's head and these gases are pushed into a tail by the solar wind. Sometimes a comet will exhibit two tails, one composed primarily of dust and the other composed of ionized gas.

Question 13

13. Use the photograph below to answer the question that follows.

The Great Red Spot of Jupiter shown in the photograph represents a:

1. deposit of iron-rich dust lying on the frozen surface of the planet from a past meteor impact.
2. persistent anticyclonic storm located between two jet streams traveling in opposite directions.
3. hole in the frozen gases making up the atmosphere caused by the impact of a large comet.
4. persistent disturbance in the planet's magnetic field caused by a slight eccentricity in its rotation.

Answer to question 13

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0009) Heat within Jupiter generates convection currents in its upper atmosphere. Warm gas rises, loses heat into space, and sinks again. Jupiter's rapid rotation subjects the gas to a strong Coriolis effect that deflects the gas into powerful jet streams. Adjacent jet streams blow in opposite directions and the gas rising between them from below is spun into huge, whirling atmospheric vortices. One extremely large vortex, the Great Red Spot, seems to be an essentially permanent feature of the planet's atmospheric circulation. Correct Response: B. (Objective 0009) Heat within Jupiter generates convection currents in its upper atmosphere. Warm gas rises, loses heat into space, and sinks again. Jupiter's rapid rotation subjects the gas to a strong Coriolis effect that deflects the gas into powerful jet streams. Adjacent jet streams blow in opposite directions and the gas rising between them from below is spun into huge, whirling atmospheric vortices. One extremely large vortex, the Great Red Spot, seems to be an essentially permanent feature of the planet's atmospheric circulation.

Question 14

14. Which of the following explanations best describes the formation of the asteroid belt between Jupiter and Mars?

1. Comets whose orbits deteriorated after repeated trips around the sun crashed into existing planets or accumulated in the empty space between Mars and Jupiter.
2. A collision between Earth and a Mars-sized planet formed the moon and numerous fragments that were thrown into orbit between Mars and Jupiter.
3. Accretion of small planetesimals in the solar disk into a new or existing planet was prevented by the immense gravitational pull of Jupiter.
4. A small planet orbiting between Mars and Jupiter collided with an interstellar object, broke apart, and was further fragmented by repeated collisions of the pieces.

Answer to question 14

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: C. (Objective 0009) Early in the formation of the solar system, the solar disk consisted of gas, dust, and small rocky or metallic bodies. Over time, these coalesced into planetesimals, which through the process of accretion became the planets. Gas giants such as Jupiter swept up gas and dust within reach of their gravitational pull, preventing formation of a new planet in what is now known as the asteroid belt. Correct Response: C. (Objective 0009) Early in the formation of the solar system, the solar disk consisted of gas, dust, and small rocky or metallic bodies. Over time, these coalesced into planetesimals, which through the process of accretion became the planets. Gas giants such as Jupiter swept up gas and dust within reach of their gravitational pull, preventing formation of a new planet in what is now known as the asteroid belt.

Question 15

15. During the winter months in Minnesota, the height of the sun above the horizon at noon is lower than it is at noon during the summer. Which of the following changes in the Earth-sun system is responsible for this difference?

1. The degree of tilt of Earth's rotational axis relative to the plane of the ecliptic changes as a result of its orbital motion.
2. The direction in which Earth's rotational axis points relative to Polaris changes over time.
3. The orientation of Earth's rotational axis relative to the sun is altered as a result of the change in its position during its orbit.
4. The tilt of the plane of Earth's elliptical orbit relative to the sun changes over the course of a year.

Answer to question 15

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: C. (Objective 0010) From the point of view of an observer in Minnesota, the apparent path of the sun above the horizon varies with the season in that the sun is higher in the sky at noon in the summer than it is in the winter. The cause of this seasonal change is a result of the fact that Earth's rotational axis is tilted 23.5 degrees with respect to the sun. As a consequence of this angle of Earth's rotational axis, the Northern Hemisphere of Earth is tilted toward the sun in the summer months, and the path of the sun across the sky is higher at noon. During the winter months, the Northern Hemisphere is tilted away from the sun, and the sun will be closer to the horizon at noon. Correct Response: C. (Objective 0010) From the point of view of an observer in Minnesota, the apparent path of the sun above the horizon varies with the season in that the sun is higher in the sky at noon in the summer than it is in the winter. The cause of this seasonal change is a result of the fact that Earth's rotational axis is tilted 23.5 degrees with respect to the sun. As a consequence of this angle of Earth's rotational axis, the Northern Hemisphere of Earth is tilted toward the sun in the summer months, and the path of the sun across the sky is higher at noon. During the winter months, the Northern Hemisphere is tilted away from the sun, and the sun will be closer to the horizon at noon.

Question 16

16. Which of the following would be one likely short-term consequence of a massive solar flare with a coronal mass ejection and accompanying geomagnetic storm?

1. an increase in severe weather events
2. the reversal of the polarity of Earth's magnetic field
3. disruption of electrical power grids
4. high doses of radiation for those living at elevations over 5,000 feet

Answer to question 16

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: C. (Objective 0010) A solar flare is a brief, bright eruption of hot gases in the sun's chromosphere. A large solar flare can be accompanied by a coronal mass ejection which sends ions, electrons, and protons out into space. The high-energy particles emitted by a large solar flare may transfer energy to Earth's magnetosphere and produce a geomagnetic storm. Magnetic fields associated with such a geomagnetic storm can produce high levels of current in long transmission lines, overloading and causing failure of transformers throughout the system. A geomagnetic storm associated with a massive solar flare was responsible for the loss of power to six million people for nine hours in the northeastern United States and Quebec in 1989. Correct Response: C. (Objective 0010) A solar flare is a brief, bright eruption of hot gases in the sun's chromosphere. A large solar flare can be accompanied by a coronal mass ejection which sends ions, electrons, and protons out into space. The high-energy particles emitted by a large solar flare may transfer energy to Earth's magnetosphere and produce a geomagnetic storm. Magnetic fields associated with such a geomagnetic storm can produce high levels of current in long transmission lines, overloading and causing failure of transformers throughout the system. A geomagnetic storm associated with a massive solar flare was responsible for the loss of power to six million people for nine hours in the northeastern United States and Quebec in 1989.

Question 17

17. The sun retains its size and shape because of the hydrostatic balance between the inward force of gravity and the outward force produced by:

1. pressure exerted by collisions between rapidly moving, densely packed atoms at high temperatures.
2. electrostatic discharge between the negatively charged core and the positively charged chromosphere.
3. movement of neutrinos and gamma rays from the core to the outer layers of the sun.
4. explosive releases of energy as the potential energy in hydrogen atoms is converted to kinetic energy.

Answer to question 17

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: A. (Objective 0010) The sun is a very massive body and its gravity exerts a powerful inward force tending to collapse the sun into a smaller and smaller ball. For the sun to remain the same size and shape, this inward force must be balanced by an equal outward force. The outward force needed to balance the inward force is the pressure exerted by heated gases within the sun. According to the ideal gas law, the strength of the pressure is proportional to density of the gas times the temperature of the gas. Gases within the deeper layers of the sun are compressed by gravity and the weight of overlying gases. As they are compressed their density increases. Compression and fusion reactions in the sun's core heat these gases to very high temperatures. Under these conditions pressure will increase, because collisions between atoms and molecules in the gases increase. These collisions increase because the atoms and molecules are moving faster at high temperatures and are closer together because of the increase in density. The outward force of this pressure balances the inward force of gravity to maintain the sun's size and shape. Correct Response: A. (Objective 0010) The sun is a very massive body and its gravity exerts a powerful inward force tending to collapse the sun into a smaller and smaller ball. For the sun to remain the same size and shape, this inward force must be balanced by an equal outward force. The outward force needed to balance the inward force is the pressure exerted by heated gases within the sun. According to the ideal gas law, the strength of the pressure is proportional to density of the gas times the temperature of the gas. Gases within the deeper layers of the sun are compressed by gravity and the weight of overlying gases. As they are compressed their density increases. Compression and fusion reactions in the sun's core heat these gases to very high temperatures. Under these conditions pressure will increase, because collisions between atoms and molecules in the gases increase. These collisions increase because the atoms and molecules are moving faster at high temperatures and are closer together because of the increase in density. The outward force of this pressure balances the inward force of gravity to maintain the sun's size and shape.

Question 18

18. Use the illustration below to answer the question that follows.

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The Sun and Earth occupy the same plane, while the plane of the moon's orbit around Earth is inclined approximately 5 point four degrees to the Earth and Sun.

Which of the following would be the result if the moon's orbit around Earth was in the same plane as Earth's orbit around the sun rather than tipped approximately 5.4° as shown in the illustration?

1. The current dark side of the moon would be visible every other month.
2. A total eclipse of the moon would occur during every full moon.
3. The full moon would rise at midnight and set at noon each day.
4. Tides at all locations around Earth would occur at the same time.

Answer to question 18

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0010) Eclipses of the moon occur when Earth is between the moon and the sun, blocking the light from the sun from reaching the moon. The eclipse is produced by Earth's shadow falling across the moon. A full moon also occurs when Earth is between the moon and the sun, and a total lunar eclipse only occurs around the time of a full moon. Because of the tilt of the moon's orbit, a full moon can occur, without an eclipse, when the moon is above or below the plane of Earth's orbit around the sun. A total lunar eclipse occurs only when the moon, Earth, and sun are aligned in a straight line and the moon is at a point where its orbit around Earth intersects with Earth's orbit around the sun. Correct Response: B. (Objective 0010) Eclipses of the moon occur when Earth is between the moon and the sun, blocking the light from the sun from reaching the moon. The eclipse is produced by Earth's shadow falling across the moon. A full moon also occurs when Earth is between the moon and the sun, and a total lunar eclipse only occurs around the time of a full moon. Because of the tilt of the moon's orbit, a full moon can occur, without an eclipse, when the moon is above or below the plane of Earth's orbit around the sun. A total lunar eclipse occurs only when the moon, Earth, and sun are aligned in a straight line and the moon is at a point where its orbit around Earth intersects with Earth's orbit around the sun.

Question 19

19. Earth's axis is tilted 23.5° with respect to the plane of its orbit around the sun. Which of the following is one consequence of this axial tilt?

1. Earth travels faster during some parts of its orbit around the sun than during other parts.
2. Aurora displays are much more common at higher latitudes than at lower latitudes.
3. Hurricanes and other major storms rotate in a counterclockwise direction in the Northern Hemisphere.
4. Annual variation in daylight hours is much greater at higher latitudes than at lower latitudes.

Answer to question 19

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: D. (Objective 0010) If Earth's axis was perpendicular to its equator, then all parts of Earth, with the exception of the poles, would receive approximately 12 hours of daylight each day throughout the year. Because the axis is tilted, different parts of Earth receive different amounts of daylight. When the axis is tilted away from the sun, higher latitudes in the Northern Hemisphere receive less than 12 hours of daylight, while higher latitudes in the Southern Hemisphere receive more. At very high latitudes, above 66.5°, the sun never sets for part of the year and never rises for another part. Correct Response: D. (Objective 0010) If Earth's axis was perpendicular to its equator, then all parts of Earth, with the exception of the poles, would receive approximately 12 hours of daylight each day throughout the year. Because the axis is tilted, different parts of Earth receive different amounts of daylight. When the axis is tilted away from the sun, higher latitudes in the Northern Hemisphere receive less than 12 hours of daylight, while higher latitudes in the Southern Hemisphere receive more. At very high latitudes, above 66.5 degrees, the sun never sets for part of the year and never rises for another part.

Question 20

20. One of the long-term consequences of Earth's precession as it rotates will be that:

1. the location of Earth's magnetic poles will change over time.
2. a different star will become the North Star as seen from Earth.
3. the plane of Earth's revolution around the sun will tilt slightly.
4. the planet Jupiter will appear to move westward relative to the stars.

Answer to question 20

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0010) In addition to its revolution around the sun and its rotation around its axis, Earth has another movement, precession. Precession is essentially a wobble of the axis, due to the gravitational pulls of the moon and sun upon the Earth. The process of axial precession takes c. 26,000 years to complete. During this time period, the orientation of Earth relative to other celestial bodies changes, and stars visible behind the sun, such as the North Star in this example, will appear in a different position to an observer than they would have previously. Correct Response: B. (Objective 0010) In addition to its revolution around the sun and its rotation around its axis, Earth has another movement, precession. Precession is essentially a wobble of the axis, due to the gravitational pulls of the moon and sun upon the Earth. The process of axial precession takes c. 26,000 years to complete. During this time period, the orientation of Earth relative to other celestial bodies changes, and stars visible behind the sun, such as the North Star in this example, will appear in a different position to an observer than they would have previously.

Question 21

21. Which of the following statements best describes why we observe meteor craters on the surface of the moon but not on Earth's land surfaces?

1. Earth's atmosphere destroys most meteors before they land.
2. The moon was formed in the solar system earlier than Earth.
3. There is no erosion occurring on the surface of the moon.
4. The composition of Earth's soil is different from the moon.

Answer to question 21

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: C. (Objective 0010) Earth and its moon are believed to be similar ages and compositions. Although there isn't life on the moon, craters are visible primarily because the moon lacks water or a significant atmosphere surface and therefore doesn't undergo erosion or weathering. Correct Response: C. (Objective 0010) Earth and its moon are believed to be similar ages and compositions. Although there isn't life on the moon, craters are visible primarily because the moon lacks water or a significant atmosphere surface and therefore doesn't undergo erosion or weathering.

Question 22

22. The extraction of natural gas from shale deposits in many parts of the United States has expanded dramatically. Which of the following is a major concern associated with the widespread use of hydraulic fracturing in the extraction of natural gas from shale deposits?

1. contamination of groundwater with the chemicals used to fracture the bedrock
2. draining of surface water into areas where bedrock has been fractured
3. explosion of natural gas seeping up into surface bedrock containing fractures
4. development of sinkholes in surface deposits overlying fractured bedrock

Answer to question 22

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Correct Response: A. (Objective 0011) Hydraulic fracturing, also known as fracking, is a process that involves the high-pressure injection of a mixture of water, sand, and chemicals into shale deposits. This high-pressure injection produces fissures within the shale, allowing the release of natural gas contained within the deposit. The gas, along with the injected liquid, is then pumped back to the surface. The wastewater mixture is then disposed of by injection into deep underground wells or moved into storage pits for further treatment and disposal. A number of scientific studies have provided evidence that chemicals contained in the fracking waste mixture have polluted drinking water via contamination of nearby ground and surface waters. Correct Response: A. (Objective 0011) Hydraulic fracturing, also known as fracking, is a process that involves the high-pressure injection of a mixture of water, sand, and chemicals into shale deposits. This high-pressure injection produces fissures within the shale, allowing the release of natural gas contained within the deposit. The gas, along with the injected liquid, is then pumped back to the surface. The wastewater mixture is then disposed of by injection into deep underground wells or moved into storage pits for further treatment and disposal. A number of scientific studies have provided evidence that chemicals contained in the fracking waste mixture have polluted drinking water via contamination of nearby ground and surface waters.

Question 23

23. Bituminous oil sands are being developed in the Canadian province of Alberta as a source of fossil fuels. This resource is more difficult to utilize than crude oil extracted from oil wells primarily because it is:

1. a semisolid fossil fuel that does not flow in pipelines.
2. a fossil fuel that is only found in deep underground deposits.
3. an explosive fossil fuel that must be treated to be safely used.
4. a fossil fuel that is found in association with pressurized natural gas.

Answer to question 23

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Correct Response: A. (Objective 0011) Canada's bituminous oil sands, or tar sands as they are often called, are a large fossil fuel resource that consists of sand, clay, water, and an extremely viscous form of petroleum known as bitumen. This highly viscous petroleum must be processed in order to be transferred by pipeline. The remote location of the bituminous oil sands in the middle of boreal forest wilderness has made both the processing and transport of this fossil fuel a significant barrier to its development. Since the oil sands must be processed where they are mined and then transported by pipeline great distances, the development of this fossil fuel resource has significant consequences for the environment. Correct Response: A. (Objective 0011) Canada's bituminous oil sands, or tar sands as they are often called, are a large fossil fuel resource that consists of sand, clay, water, and an extremely viscous form of petroleum known as bitumen. This highly viscous petroleum must be processed in order to be transferred by pipeline. The remote location of the bituminous oil sands in the middle of boreal forest wilderness has made both the processing and transport of this fossil fuel a significant barrier to its development. Since the oil sands must be processed where they are mined and then transported by pipeline great distances, the development of this fossil fuel resource has significant consequences for the environment.

Question 24

24. Some of the best soils in the Midwest formed in loess. Which of the following scenarios best describes the formation of the extensive loess deposits of the Midwest?

1. Peat bogs that existed during an extended pluvial period of the late Pleistocene dried out, producing sediments rich in organic matter.
2. As continental glaciers were retreating into Canada, strong winds deposited thick layers of silt derived from fine glacial sediments.
3. Outwash from retreating continental glaciers produced large amounts of clay-rich water that was deposited at the bottom of temporary lakes.
4. As large and shallow glacial lakes began drying up, the water in the lakes became supersaturated, causing the precipitation of minerals

Answer to question 24

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0011) The loess-derived soils of the Midwest formed from loess deposits that are composed primarily of wind-blown silt and small amounts of clay and fine sand. The large amounts of silt that make up the majority of loess deposits are derived from fine sediments deposited by braided glacial outwash streams during glacial retreat. These fine sediments were then picked up by strong periglacial winds and redeposited as thick accumulations of loess. Correct Response: B. (Objective 0011) The loess-derived soils of the Midwest formed from loess deposits that are composed primarily of wind-blown silt and small amounts of clay and fine sand. The large amounts of silt that make up the majority of loess deposits are derived from fine sediments deposited by braided glacial outwash streams during glacial retreat. These fine sediments were then picked up by strong periglacial winds and redeposited as thick accumulations of loess.

Question 25

25. Groundwater aquifers are sometimes located in deposits of unconsolidated sediments. The rate that water can be pumped from a groundwater aquifer composed of sediments is closely related to the type of sediment in the deposit and the packing of sedimentary grains. Given these facts, the rate at which groundwater could be pumped from an aquifer would most likely be greatest from an aquifer composed of which of the following types of sediments?

1. silty fine sand with high storage capacity
2. clay particles with high porosity
3. coarse sand and gravel with high intrinsic permeability
4. fine sand and silt with high compressibility

Answer to question 25

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Correct Response: C. (Objective 0011) Sand and gravel deposits with high intrinsic permeability make excellent aquifers because intrinsic permeability describes the ease with which a porous medium transmits water. Porosity of the sediments is important because it represents the void space between sediment grains that can hold water; however, some sediments (e.g., clay) can be very porous, but still not be useable sources of groundwater because the pore spaces between the clay particles are not connected. The very low intrinsic permeability of clay deposits makes clay an aquitard that effectively blocks the flow of groundwater. Correct Response: C. (Objective 0011) Sand and gravel deposits with high intrinsic permeability make excellent aquifers because intrinsic permeability describes the ease with which a porous medium transmits water. Porosity of the sediments is important because it represents the void space between sediment grains that can hold water; however, some sediments (e.g., clay) can be very porous, but still not be useable sources of groundwater because the pore spaces between the clay particles are not connected. The very low intrinsic permeability of clay deposits makes clay an aquitard that effectively blocks the flow of groundwater.

Question 26

26. High concentrations of ozone in the lower troposphere are linked to the combustion of fossil fuels. This ozone pollution has been shown to affect the:

1. incidence of skin cancer.
2. reproduction of amphibians.
3. acidity of precipitation.
4. growth of plants.

Answer to question 26

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Correct Response: D. (Objective 0011) Ozone enters leaves through stomata when plants are exchanging gases with their environment. The ozone molecule is a strong oxidizing agent that causes a variety of problems in a range of plant species. Long-term research on the effects of ozone on crop plants carried out by the United States government has demonstrated that exposure to ozone reduces crop yields by interfering with photosynthesis and damaging plant tissue. Correct Response: D. (Objective 0011) Ozone enters leaves through stomata when plants are exchanging gases with their environment. The ozone molecule is a strong oxidizing agent that causes a variety of problems in a range of plant species. Long-term research on the effects of ozone on crop plants carried out by the United States government has demonstrated that exposure to ozone reduces crop yields by interfering with photosynthesis and damaging plant tissue.

Question 27

Use the following excerpt from a student essay about crude oil to answer the question that follows.

Crude oil comes from the partial decomposition of ancient plants, animals, and organic matter buried under oceans or in the ground in areas like the North Pole. All fossil fuels were formed underground during prehistoric times. Oil has a wide variety of uses and is often used in cosmetics, medicine, paint, lubricants, and as a fuel. Because the oil formed at one point in history, there is no more once people use it all. The rate of oil consumption has been constantly going up over the last 100 years, so the supply of oil still in the ground has been going down. Alternate forms of energy and biofuels have not been very effective in helping to conserve oil supplies.

27. Which of the following statements corrects a misconception expressed in the student's essay?

1. Crude oil isn't found at either of Earth's poles.
2. Rates of fossil fuel consumption are declining.
3. Biofuels are priced competitively with gasoline.
4. New oil reserves are still being created.

Answer to question 27

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Correct Response: D. (Objective 0011) The primary misconception expressed by the student is that all fossil fuels, such as oil, were formed in the past. Fossils, which could become fossil fuels, are still being formed today. However, this process took millions of years in the past. Therefore, the rate of replenishment of fossil fuels is very slow compared to the rate of oil consumption—too slow to be an effective solution for our energy needs. Correct Response: D. (Objective 0011) The primary misconception expressed by the student is that all fossil fuels, such as oil, were formed in the past. Fossils, which could become fossil fuels, are still being formed today. However, this process took millions of years in the past. Therefore, the rate of replenishment of fossil fuels is very slow compared to the rate of oil consumption—too slow to be an effective solution for our energy needs.

Question 28

28. Photochemical smog forms in urban areas as a result of the action of sunlight on air pollution. Which of the following chemical reactions begins the multistep process of photochemical smog formation?

1. Nitrogen dioxide generated as a result of combustion is broken down by sunlight, releasing oxygen atoms that react with water and molecular oxygen.
2. Ozone occurring naturally in the atmosphere is broken down by sunlight, generating oxygen atoms that react with hydrocarbons from automobile exhaust.
3. Hydroxyl molecules that break into hydrogen and oxygen atoms in the presence of sunlight react with molecular oxygen to produce ozone.
4. Water vapor reacts with carbon monoxide and carbon dioxide in the presence of sunlight to produce a variety of volatile hydrocarbons.

Answer to question 28

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Correct Response: A. (Objective 0012) Photochemical smog is a serious air pollution problem that is particularly bad in cities with heavy automobile traffic and sunny weather. The production of photochemical smog begins with the release of nitric oxide (NO) from combustion in automobile engines. Nitric oxide combines with molecular oxygen (O₂) to produce nitrogen dioxide (NO₂). In the presence of sunlight this compound generates oxygen atoms—a highly reactive species. The free oxygen atoms then combine with water to produce hydroxyl radicals, which in turn react with hydrocarbons in the atmosphere to form hydrocarbon radicals, major components of photochemical smog. Atomic oxygen also combines with molecular oxygen to produce ozone (O₃), another constituent of photochemical smog. Correct Response: A. (Objective 0012) Photochemical smog is a serious air pollution problem that is particularly bad in cities with heavy automobile traffic and sunny weather. The production of photochemical smog begins with the release of nitric oxide (upper N upper O) from combustion in automobile engines. Nitric oxide combines with molecular oxygen (upper O sub two) to produce nitrogen dioxide (upper N upper O sub two). In the presence of sunlight this compound generates oxygen atoms—a highly reactive species. The free oxygen atoms then combine with water to produce hydroxyl radicals, which in turn react with hydrocarbons in the atmosphere to form hydrocarbon radicals, major components of photochemical smog. Atomic oxygen also combines with molecular oxygen to produce ozone (upper O sub three), another constituent of photochemical smog.

Question 29

29. Which of the following sources of water pollution provides the best example of nonpoint source pollution?

1. hot water released by nuclear power plants
2. agricultural runoff from cultivated fields
3. landfill seepage of heavy metals
4. overflow from sewage treatment plants

Answer to question 29

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Correct Response: B. (Objective 0012) Nonpoint source pollution is defined as diffuse pollution that does not come from a single discrete source, but instead is produced from nonspecific locations. General runoff of sediments, fertilizers, pesticides, and other materials from farms is one of the best examples of nonpoint source pollution; however, urban runoff that is not collected in storm drains but instead flows directly into waterways is another example of nonpoint source pollution. Correct Response: B. (Objective 0012) Nonpoint source pollution is defined as diffuse pollution that does not come from a single discrete source, but instead is produced from nonspecific locations. General runoff of sediments, fertilizers, pesticides, and other materials from farms is one of the best examples of nonpoint source pollution; however, urban runoff that is not collected in storm drains but instead flows directly into waterways is another example of nonpoint source pollution.

Question 30

30. The widespread use of woodstoves in some parts of the country has increased local air pollution during the winter months. Which of the following atmospheric phenomena increases the concentration of wood smoke in valleys at this time of year?

1. advection fog that forms early in the morning
2. a lapse rate above 4°F per 1,000 feet
3. downslope winds that develop in the evening
4. a layer of warmer air overlying cold air

Answer to question 30

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Correct Response: D. (Objective 0012) Normally, the temperature of the atmosphere decreases with increased elevation. This situation supports mixing of near-surface air with air higher up in the atmosphere. On long winter nights the air near the ground surface may cool more rapidly than the air at higher elevations. In a valley in the winter this situation can produce a temperature inversion in the atmosphere that traps the pollution from woodstoves near the surface. The cold denser air at the bottom of the valley becomes trapped below slightly warmer air. The topography of a valley can make the situation worse as the air may be protected by the valley walls from winds that might help mix the atmosphere and reduce the concentration of wood smoke pollution near the surface. Correct Response: D. (Objective 0012) Normally, the temperature of the atmosphere decreases with increased elevation. This situation supports mixing of near-surface air with air higher up in the atmosphere. On long winter nights the air near the ground surface may cool more rapidly than the air at higher elevations. In a valley in the winter this situation can produce a temperature inversion in the atmosphere that traps the pollution from woodstoves near the surface. The cold denser air at the bottom of the valley becomes trapped below slightly warmer air. The topography of a valley can make the situation worse as the air may be protected by the valley walls from winds that might help mix the atmosphere and reduce the concentration of wood smoke pollution near the surface.

Question 31

31. As a hurricane makes landfall along the coast of the United States, the height of the storm surge is typically much greater to the right of where the eye of the hurricane makes landfall. The underlying cause for this phenomenon is the:

1. difference in atmospheric pressure on either side of the eye.
2. difference in precipitation on either side of the eye.
3. frictional effect of the land on the leading edge of the hurricane.
4. direction of rotation of the hurricane.

Answer to question 31

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: D. (Objective 0012) Hurricanes are massive low-pressure systems and in the Northern Hemisphere winds flow in a counterclockwise direction around areas of low pressure. As a result of the wind direction associated with low-pressure systems, the counterclockwise winds in a hurricane making landfall in the United States will push water toward the right of the eye with more force than the winds to the left of the eye. To the left of the eye, the hurricane's winds will have rotated across the land surface and will actually push water away from the coast, significantly reducing the height of the storm surge to the left of the eye. Other factors do affect the storm surge, including the very low pressure associated with hurricanes. This phenomenon raises the elevation of the ocean surface across the whole area of low pressure. Ocean tides can also play a role as a storm surge during a normally high tide will rise higher than a storm surge that occurs at low tide. The topography of the near-shore ocean floor and the shape of the coastline where the hurricane comes ashore can also affect the height of a storm surge. Correct Response: D. (Objective 0012) Hurricanes are massive low-pressure systems and in the Northern Hemisphere winds flow in a counterclockwise direction around areas of low pressure. As a result of the wind direction associated with low-pressure systems, the counterclockwise winds in a hurricane making landfall in the United States will push water toward the right of the eye with more force than the winds to the left of the eye. To the left of the eye, the hurricane's winds will have rotated across the land surface and will actually push water away from the coast, significantly reducing the height of the storm surge to the left of the eye. Other factors do affect the storm surge, including the very low pressure associated with hurricanes. This phenomenon raises the elevation of the ocean surface across the whole area of low pressure. Ocean tides can also play a role as a storm surge during a normally high tide will rise higher than a storm surge that occurs at low tide. The topography of the near-shore ocean floor and the shape of the coastline where the hurricane comes ashore can also affect the height of a storm surge.

Question 32

32. Industrial electrostatic precipitators are used primarily to remove:

1. heavy metal contaminants from wastewater used in various manufacturing processes, such as electroplating.
2. ozone from the exhaust systems of large vehicles powered by internal-combustion engines such as trucks, trains, or ships.
3. bacterial contaminants from sewage systems before the treated water is discharged into surface or ocean waters.
4. fine particulate matter such as dust, ash, and smoke from smokestacks of fossil-fuel electricity-generating plants.

Answer to question 32

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Correct Response: D. (Objective 0012) Electrostatic precipitators work on the principle that particles with opposite electrical charges attract. As smoke rises up a chimney flue, it passes next to a series of electrodes that have a high negative charge. The particles in the smoke pick up the negative charge as they rise. Farther up the flue, there are other electrodes, usually in the form of plates that have a high positive charge. The negatively charged particles are attracted to the positively charged plates and stick to them, removing them from the column of rising air. Precipitators are not effective in removing all pollutants, but in combination with other technologies, can eliminate most pollutants from power plant emissions. Correct Response: D. (Objective 0012) Electrostatic precipitators work on the principle that particles with opposite electrical charges attract. As smoke rises up a chimney flue, it passes next to a series of electrodes that have a high negative charge. The particles in the smoke pick up the negative charge as they rise. Farther up the flue, there are other electrodes, usually in the form of plates that have a high positive charge. The negatively charged particles are attracted to the positively charged plates and stick to them, removing them from the column of rising air. Precipitators are not effective in removing all pollutants, but in combination with other technologies, can eliminate most pollutants from power plant emissions.

Question 33

33. In the United States, the main source of lead in drinking water is:

1. point source discharge of industrial wastewater into surface waters used as drinking water sources.
2. non-point runoff into groundwater and surface waters from agricultural fields where lead-based pesticides have been used.
3. corrosion of old municipal water pipes or pipes, solder, and fixtures in individual houses or apartment buildings.
4. leaching of lead into aquifers from landfills where lead-acid batteries have been disposed of improperly.

Answer to question 33

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: C. (Objective 0012) Lead is a serious contaminant in many older buildings. The major source of lead in homes is peeling and flaking lead paint; however, it is also frequently present in the drinking water. When water stands in pipes overnight, lead can leach into it from pipes, solder, or fixtures (particularly chrome or brass). Municipal water sources can also be contaminated by lead if the water is flowing through old pipes. Lead piping and solder have been banned since 1986, but are still present in many homes built before that date. Correct Response: C. (Objective 0012) Lead is a serious contaminant in many older buildings. The major source of lead in homes is peeling and flaking lead paint; however, it is also frequently present in the drinking water. When water stands in pipes overnight, lead can leach into it from pipes, solder, or fixtures (particularly chrome or brass). Municipal water sources can also be contaminated by lead if the water is flowing through old pipes. Lead piping and solder have been banned since 1986, but are still present in many homes built before that date.

Question 34

34. Which of the following atmospheric changes drives the onset of the wet phase of the Indian monsoon?

1. the development of a large and semipermanent upper-level low-pressure system over the Indian Ocean during the fall
2. the reversal of the trade winds as the intertropical convergence zone shifts to the south of the Indian Ocean during the winter
3. the development of a thermal low-pressure system over the continental interior of northern India as the land heats up during the summer
4. the shift in the position of the subtropical jet stream to the north of the Indian subcontinent during the early spring

Answer to question 34

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Correct Response: C. (Objective 0013) The amount of solar radiation received by the continental interior of northern India increases following the Spring Equinox. As the land heats up, a thermal low-pressure trough is formed. Surrounding seas heat up much more slowly. The pressure gradient that is produced ultimately affects the prevailing wind patterns and moisture-laden winds blowing from the southwest to produce heavy rainfall. Correct Response: C. (Objective 0013) The amount of solar radiation received by the continental interior of northern India increases following the Spring Equinox. As the land heats up, a thermal low-pressure trough is formed. Surrounding seas heat up much more slowly. The pressure gradient that is produced ultimately affects the prevailing wind patterns and moisture-laden winds blowing from the southwest to produce heavy rainfall.

Question 35

35. The Köppen climate classification system uses which of the following characteristics of climate zones to determine the geographic boundaries between different climate zones?

1. vegetation patterns
2. precipitation variability
3. soil characteristics
4. temperature extremes

Answer to question 35

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Correct Response: A. (Objective 0013) The Köppen climate classification system uses patterns of vegetation to establish boundaries between different climate zones. Köppen believed that the types of native vegetation adapted to a region are the most appropriate expression of average climate conditions; therefore he used patterns of vegetation to define boundaries between climate zones. The zones are characterized numerically by temperature and precipitation averages. The Köppen climate classification system has been widely used throughout the world; however it has frequently been modified by climatologists working to refine Köppen's system. Correct Response: A. (Objective 0013) The Köppen climate classification system uses patterns of vegetation to establish boundaries between different climate zones. Köppen believed that the types of native vegetation adapted to a region are the most appropriate expression of average climate conditions; therefore he used patterns of vegetation to define boundaries between climate zones. The zones are characterized numerically by temperature and precipitation averages. The Köppen climate classification system has been widely used throughout the world; however it has frequently been modified by climatologists working to refine Köppen's system.

Question 36

36. Which of the following is a characteristic impact of a strong La Niña on the United States?

1. above-average precipitation and below-average temperatures in the Southeast
2. above-average precipitation and below-average temperatures in the Pacific Northwest
3. above-average temperatures and above-average precipitation in the Southwest
4. above-average temperatures and below-average precipitation in the Upper Midwest

Answer to question 36

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: B. (Objective 0013) The El Niño-Southern Oscillation (ENSO) climate phenomenon includes three different phases: El Niño, La Niña, and a neutral phase during which neither an El Niño or La Niña is dominant. During these different phases, climate parameters in equatorial regions of the Pacific Ocean change in ways that alter the global climate system. These changes involve the atmospheric pressure on either side of the Pacific Ocean, the strength and direction of the trade winds, and the temperature of the Pacific Ocean's water above the thermocline. A strong La Niña or El Niño triggers shifts in the jet stream that have significant and somewhat predictable consequences for the average weather conditions in certain regions of the United States. During a strong La Niña, characteristic changes in the normal weather include warmer and drier conditions in the Southwest and cooler and wetter weather in the Pacific Northwest. The Southeast tends to be drier than usual and the Midwest and Great Lakes regions are often wetter than usual. Since many other climate variables come into play in these different parts of the United States, no two La Niña events will have precisely the same effects on the average temperature and precipitation in a particular region. Years of data have shown that these shifts in regional climate usually occur in some form during a La Niña, providing climatologists with a basis for predicting where precipitation and temperature anomalies are likely to occur during the coming months. Correct Response: B. (Objective 0013) The El Niño-Southern Oscillation (E N S O) climate phenomenon includes three different phases: El Niño, La Niña, and a neutral phase during which neither an El Niño or La Niña is dominant. During these different phases, climate parameters in equatorial regions of the Pacific Ocean change in ways that alter the global climate system. These changes involve the atmospheric pressure on either side of the Pacific Ocean, the strength and direction of the trade winds, and the temperature of the Pacific Ocean's water above the thermocline. A strong La Niña or El Niño triggers shifts in the jet stream that have significant and somewhat predictable consequences for the average weather conditions in certain regions of the United States. During a strong La Niña, characteristic changes in the normal weather include warmer and drier conditions in the Southwest and cooler and wetter weather in the Pacific Northwest. The Southeast tends to be drier than usual and the Midwest and Great Lakes regions are often wetter than usual. Since many other climate variables come into play in these different parts of the United States, no two La Niña events will have precisely the same effects on the average temperature and precipitation in a particular region. Years of data have shown that these shifts in regional climate usually occur in some form during a La Niña, providing climatologists with a basis for predicting where precipitation and temperature anomalies are likely to occur during the coming months.

Question 37

37. Which of the following areas of scientific research has provided the most detailed information about how ecosystems have adapted to climate changes during the past 12,000 years?

1. glaciology
2. limnology
3. dendrochronology
4. palynology

Answer to question 37

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Correct Response: D. (Objective 0013) Palynology involves the study of organic microfossils, especially pollen grains and spores. Scientists studying the dramatic climate shifts that occurred following the melting of the Pleistocene ice sheets use palynological data to establish when different plant species and the ecosystems they represent became established in different regions. Typically, palynological data is collected from drill cores of lake, pond, or swamp sediments. Organic matter in these cores can be dated using radiometric dating. Stratigraphic analysis is also used to establish the relative ages of sediments and the microfossils they contain. Within the sediments are found snapshots of the ecosystems that were in existence at the time the sediments were deposited. The microfauna, pollen, and spores that were being released by plant species living in the area collect in ponds and lakes and then are incorporated into the sedimentary layers building on the bottom of the lake. Palynology continues to be one of the most widely used tools for establishing the ecosystems that existed in the relatively recent geologic past and, by analogy with contemporary ecosystems, the climate conditions that likely existed at that time. Correct Response: D. (Objective 0013) Palynology involves the study of organic microfossils, especially pollen grains and spores. Scientists studying the dramatic climate shifts that occurred following the melting of the Pleistocene ice sheets use palynological data to establish when different plant species and the ecosystems they represent became established in different regions. Typically, palynological data is collected from drill cores of lake, pond, or swamp sediments. Organic matter in these cores can be dated using radiometric dating. Stratigraphic analysis is also used to establish the relative ages of sediments and the microfossils they contain. Within the sediments are found snapshots of the ecosystems that were in existence at the time the sediments were deposited. The microfauna, pollen, and spores that were being released by plant species living in the area collect in ponds and lakes and then are incorporated into the sedimentary layers building on the bottom of the lake. Palynology continues to be one of the most widely used tools for establishing the ecosystems that existed in the relatively recent geologic past and, by analogy with contemporary ecosystems, the climate conditions that likely existed at that time.

Question 38

38. Computer models that are used to make predictions about how Earth's climate will change with increased concentrations of carbon dioxide in the atmosphere consistently show which of the following consequences of increased atmospheric carbon dioxide levels?

1. increased intensity of precipitation events and droughts
2. higher pH and salinity of ocean surface waters
3. increased circulation rates of the oceans' major currents
4. colder winters and hotter summers

Answer to question 38

Answer Enter to expand or collapse answer. Answer expanded

Correct Response: A. (Objective 0013) Scientists have developed a variety of climate models that run with different parameters to help determine how increased carbon dioxide levels in the atmosphere will affect Earth's climate system. One consistent phenomenon that shows up in different models is that precipitation patterns will change, increasing drought in some regions, while causing extreme precipitation events in others. The National Oceanic and Atmospheric Administration (NOAA) cites an enhancement of the hydrologic cycle as a consistent feature of different computer models. They describe this as dry areas becoming drier and wet areas becoming wetter. Correct Response: A. (Objective 0013) Scientists have developed a variety of climate models that run with different parameters to help determine how increased carbon dioxide levels in the atmosphere will affect Earth's climate system. One consistent phenomenon that shows up in different models is that precipitation patterns will change, increasing drought in some regions, while causing extreme precipitation events in others. The National Oceanic and Atmospheric Administration (N O A A) cites an enhancement of the hydrologic cycle as a consistent feature of different computer models. They describe this as dry areas becoming drier and wet areas becoming wetter.

Question 39

39. The climate of Minnesota is characterized by hot summers and cold winters. However, the Arrowhead region in the far northeastern part of Minnesota experiences cooler summers and warmer winters than more southern and western parts of the state. Which of the following phenomena is the primary reason for these differences?

1. The jet stream dips south near Grand Marais, bringing cool air from Canada in the summer and warmer southern air in the winter.
2. This region is a high plateau that is swept by cool northwest winds in summer and that receives high solar radiation in the winter.
3. The waters of Lake Superior bordering this region act as a heat sink, trapping heat in summer and slowly releasing it during winter.
4. This region lies along the border between the colder continental and warmer eastern climate systems that shift back and forth seasonally.

Answer to question 39

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Correct Response: C. (Objective 0013) The Arrowhead region of Minnesota borders Lake Superior. While the rest of the state has a fairly typical continental climate, with hot summers and cold winters, in this region, the lake moderates both the summer heat and winter cold. Water can absorb and hold a large amount of heat and releases it much more slowly than land. Thus, locations near coasts of large lakes or oceans exhibit less seasonal variation in temperature than inland locations. In the Arrowhead region, this effect is confined to a fairly narrow strip of land along the lakeshore that is sheltered from the prevailing northwest winds by the Sawtooth Mountains. Correct Response: C. (Objective 0013) The Arrowhead region of Minnesota borders Lake Superior. While the rest of the state has a fairly typical continental climate, with hot summers and cold winters, in this region, the lake moderates both the summer heat and winter cold. Water can absorb and hold a large amount of heat and releases it much more slowly than land. Thus, locations near coasts of large lakes or oceans exhibit less seasonal variation in temperature than inland locations. In the Arrowhead region, this effect is confined to a fairly narrow strip of land along the lakeshore that is sheltered from the prevailing northwest winds by the Sawtooth Mountains.

Question 40

40. Warming surface temperatures of high latitude oceans due to anthropogenic climate change further affect global climate primarily by:

1. stimulating plankton blooms that increase the albedo of the oceans.
2. intensifying thermohaline circulation and heat transfer from the tropics to the poles.
3. reducing atmospheric circulation in the north and south polar cells.
4. increasing evaporation and the amount of water vapor in the atmosphere.

Answer to question 40

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Correct Response: D. (Objective 0013) Most evaporation in Earth's water cycle occurs over the oceans. More evaporation occurs where ocean surfaces are warmer—in areas of low latitude, such as near the Equator. Global climate change has led to increasingly warmer surfaces of high latitude oceans (e.g., North Atlantic, Bering Sea); therefore, these areas now have increasing evaporation, which in turn leads to increased water vapor in the atmosphere. Correct Response: D. (Objective 0013) Most evaporation in Earth's water cycle occurs over the oceans. More evaporation occurs where ocean surfaces are warmer—in areas of low latitude, such as near the Equator. Global climate change has led to increasingly warmer surfaces of high latitude oceans (e.g., North Atlantic, Bering Sea); therefore, these areas now have increasing evaporation, which in turn leads to increased water vapor in the atmosphere.