ACT Science : How to find conflicting viewpoints in earth and space sciences

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #941 : Act Science

Global warming is defined as the slow increase in the temperature of the earth’s atmosphere and is caused by pollutants and carbon dioxide (CO2). While the gradual increase in temperature cannot be refuted, scientists argue over the cause.

 Scientist 1:

Global warming is caused by increases in atmospheric CO2, which is directly created by humans and their consumption of fossil fuels. The natural CO2 released from carbon sinks has a different isotopic ratio from the CO2 released from fossil fuels. Current measurements of the radioactive isotopes of CO2 show that it is from human activity, not from nature. The Earth’s carbon sinks cannot absorb these large amounts of unnatural CO2 emissions. About fifty percent of the CO2 produced by mankind remains in the atmosphere, unable to be absorbed.

Scientist 2:

The rise in atmospheric CO2 levels are a result of global warming, not the cause of it. When the temperature increases, the CO2 in carbon sinks is released. While humans do cause release of CO2, the carbon sinks absorb it. The activity of the carbon sinks increases to allow for higher levels of CO2 absorption. Proponents for human causation of global warming point to the warming and cooling of the stratosphere, however, these temperature fluctuations are caused by changes in the sun’s heat. These proponents also look at the acidity of the ocean as evidence of human causation, however, the rise in ocean acidity is within the normal range of fluctuations over the past ten thousand years.

Upon what part of the global warming discussion do both Scientist 1 and Scientist 2 agree?

Possible Answers:

Humans are one of the causes of the increased release of CO2.

Humans are the cause of global warming.

Carbon sinks absorb all of the CO2 emissions by increasing their activity.

CO2 from humans is more abundant than CO2 from carbon sinks.

Carbon sinks cannot absorb the large amounts of unnatural CO2 emissions.

Correct answer:

Humans are one of the causes of the increased release of CO2.

Explanation:

Both scientists admit that humans have contributed to an increase in CO2 being released into the atmosphere, however they have differing opinions on the effect of this release. Scientist 1 believes the CO2 from humans is the direct cause of global warming. Scientist 2 believes that while humans release CO2, the CO2 is absorbed by carbon sinks and is not the reason for global warming.

Example Question #942 : Act Science

According to the Big Bang theory, which proposes that the universe is roughly 13.7 billion years old, all matter and energy were at one time compressed into a single microscopic point. This point then exploded outward in all directions in a rapid expansion. The expansion has continued to the present day, which has allowed matter to cool to a state at which stable atomic components can form. The Big Bang theory proposes that our universe is finite in age, and since nothing can travel faster than the speed of light, there exists a cosmological horizon, which is the maximum distance light or energy could have travelled since the occurrence of the Big Bang. Since the universe is still expanding, however, regions of space that are visible from our vantage point are not within each other's cosmological horizons. For example, if galaxy A is 10 billion light years away from us, and galaxy B is 10 billion light years away from us in the opposite direction, there is a total distance of 20 billion light years between them. The universe has only existed long enough for light, energy, or information to travel 13.7 billion light years between them; thus, it is not possible for any contact to have been made between the two galaxies. Yet, even these vastly separated regions of space have been observed to be extremely homogeneous—they have remarkably similar features and properties despite being so far away from each other. The question, therefore, is what caused this apparent homogeneity observed in the universe. If matter rapidly expanded outward, why does the universe have such a uniform appearance in every direction? If the Big Bang theory is correct, some explanation for this horizon problem is needed.

Scientist 1

In the current state of the universe there exist regions that lie beyond the cosmological horizons of others, and therefore cannot possibly be influenced by them. This was not always the case. At a point in time mere microseconds after the Big Bang, all of the matter in the universe experienced a period of exponential expansion, known as inflation, before the rate of expansion fell to a more stable level. This inflation led to all regions of the universe having homogeneous features, even though they are not capable of affecting one another in any way in their current state.

Scientist 2

Although there is ample evidence that a Big Bang occurred, the horizon problem, as well as the flatness problem, suggest that the Big Bang is not the full story of the inception of the universe. The horizon problem can be solved if, instead of viewing the Big Bang as the "beginning of everything," we stipulate that the expansion seen after the Big Bang was already occurring for some time before the Big Bang occurred. This marks the Big Bang as a sort of "causal horizon," which disallows us from directly observing evidence from any period beforehand. If we assume the universe is cyclic, the homogeneity of the universe is explained as the result of a continuous cycle of expansion and compression, which would naturally lead to a universe having uniform features.

Assuming that all observed evidence to this point is correct, if a new theory were proposed to explain the origins of the universe, what feature must it be able to explain?

Possible Answers:

The lack of data prior to the Big Bang

The cyclic nature of the universe

The vast distances between regions of space

The apparent homogeneity of very distant regions of the universe

The brief period of rapid expansion shortly after the Big Bang

Correct answer:

The apparent homogeneity of very distant regions of the universe

Explanation:

The only feature described here that any new theory would have to explain is the same feature that the two scientists' theories attempt to explain: the apparent homogeneity in very distant regions of the universe. All the other answer choices either assume one of the two scientists' theories is true, or are not features that a theory of the origins of the universe would have to explain.

Example Question #943 : Act Science

According to the Big Bang theory, which proposes that the universe is roughly 13.7 billion years old, all matter and energy were at one time compressed into a single microscopic point. This point then exploded outward in all directions in a rapid expansion. The expansion has continued to the present day, which has allowed matter to cool to a state at which stable atomic components can form. The Big Bang theory proposes that our universe is finite in age, and since nothing can travel faster than the speed of light, there exists a cosmological horizon, which is the maximum distance light or energy could have travelled since the occurrence of the Big Bang. Since the universe is still expanding, however, regions of space that are visible from our vantage point are not within each other's cosmological horizons. For example, if galaxy A is 10 billion light years away from us, and galaxy B is 10 billion light years away from us in the opposite direction, there is a total distance of 20 billion light years between them. The universe has only existed long enough for light, energy, or information to travel 13.7 billion light years between them; thus, it is not possible for any contact to have been made between the two galaxies. Yet, even these vastly separated regions of space have been observed to be extremely homogeneous—they have remarkably similar features and properties despite being so far away from each other. The question, therefore, is what caused this apparent homogeneity observed in the universe. If matter rapidly expanded outward, why does the universe have such a uniform appearance in every direction? If the Big Bang theory is correct, some explanation for this horizon problem is needed.

Scientist 1

In the current state of the universe there exist regions that lie beyond the cosmological horizons of others, and therefore cannot possibly be influenced by them. This was not always the case. At a point in time mere microseconds after the Big Bang, all of the matter in the universe experienced a period of exponential expansion, known as inflation, before the rate of expansion fell to a more stable level. This inflation led to all regions of the universe having homogeneous features, even though they are not capable of affecting one another in any way in their current state.

Scientist 2

Although there is ample evidence that a Big Bang occurred, the horizon problem, as well as the flatness problem, suggest that the Big Bang is not the full story of the inception of the universe. The horizon problem can be solved if, instead of viewing the Big Bang as the "beginning of everything," we stipulate that the expansion seen after the Big Bang was already occurring for some time before the Big Bang occurred. This marks the Big Bang as a sort of "causal horizon," which disallows us from directly observing evidence from any period beforehand. If we assume the universe is cyclic, the homogeneity of the universe is explained as the result of a continuous cycle of expansion and compression, which would naturally lead to a universe having uniform features.

It can be inferred from Scientist 2's statement that the flatness problem __________.

Possible Answers:

would not occur in models of the universe that did not involve a Big Bang

is caused by the horizon problem

is another unexplained inconsistency between the predictions of the Big Bang theory and observed evidence

is only a problem for the inflation theory

is observed in regions of the universe too far apart to be within each other's cosmological horizons

Correct answer:

is another unexplained inconsistency between the predictions of the Big Bang theory and observed evidence

Explanation:

Scientist 2 alludes to "the flatness problem" to suggest that it and the horizon problem demonstrate that the Big Bang "is not the full story of the inception of the universe."

This suggests that the flatness problem is related to the predictions of the Big Bang theory and, like the horizon problem, describes a discrepancy between the predictions of that theory and the observed evidence. The other answer choices do not reflect this similarity or are not based on the passage at all.

Example Question #941 : Act Science

According to the Big Bang theory, which proposes that the universe is roughly 13.7 billion years old, all matter and energy were at one time compressed into a single microscopic point. This point then exploded outward in all directions in a rapid expansion. The expansion has continued to the present day, which has allowed matter to cool to a state at which stable atomic components can form. The Big Bang theory proposes that our universe is finite in age, and since nothing can travel faster than the speed of light, there exists a cosmological horizon, which is the maximum distance light or energy could have travelled since the occurrence of the Big Bang. Since the universe is still expanding, however, regions of space that are visible from our vantage point are not within each other's cosmological horizons. For example, if galaxy A is 10 billion light years away from us, and galaxy B is 10 billion light years away from us in the opposite direction, there is a total distance of 20 billion light years between them. The universe has only existed long enough for light, energy, or information to travel 13.7 billion light years between them; thus, it is not possible for any contact to have been made between the two galaxies. Yet, even these vastly separated regions of space have been observed to be extremely homogeneous—they have remarkably similar features and properties despite being so far away from each other. The question, therefore, is what caused this apparent homogeneity observed in the universe. If matter rapidly expanded outward, why does the universe have such a uniform appearance in every direction? If the Big Bang theory is correct, some explanation for this horizon problem is needed.

Scientist 1

In the current state of the universe there exist regions that lie beyond the cosmological horizons of others, and therefore cannot possibly be influenced by them. This was not always the case. At a point in time mere microseconds after the Big Bang, all of the matter in the universe experienced a period of exponential expansion, known as inflation, before the rate of expansion fell to a more stable level. This inflation led to all regions of the universe having homogeneous features, even though they are not capable of affecting one another in any way in their current state.

Scientist 2

Although there is ample evidence that a Big Bang occurred, the horizon problem, as well as the flatness problem, suggest that the Big Bang is not the full story of the inception of the universe. The horizon problem can be solved if, instead of viewing the Big Bang as the "beginning of everything," we stipulate that the expansion seen after the Big Bang was already occurring for some time before the Big Bang occurred. This marks the Big Bang as a sort of "causal horizon," which disallows us from directly observing evidence from any period beforehand. If we assume the universe is cyclic, the homogeneity of the universe is explained as the result of a continuous cycle of expansion and compression, which would naturally lead to a universe having uniform features.

From the context of the passage, "light year" most nearly means __________.

Possible Answers:

a prediction of the Big Bang theory that causes the horizon problem

a unit of distance equal to the distance light can travel in one year

a speed at which light travels between regions of the universe that are very far apart

a measure of the amount of time since the Big Bang occurred

a measurement of distance based on how far away light can be observed in the universe

Correct answer:

a unit of distance equal to the distance light can travel in one year

Explanation:

In the context of the passage, "light year" is used to describe how far apart two hypothetical galaxies are in space; therefore, it is a measure of distance. Essentially, a "light year" is the distance that can be travelled at the speed of light over the period of one year.

Since distance is inherently related to speed and time, there is a finite distance that can be travelled at a given speed (the speed of light) over a given time (the age of the universe). This finite distance is the cosmological horizon referred to in the passage.

Example Question #951 : Act Science

According to the Big Bang theory, which proposes that the universe is roughly 13.7 billion years old, all matter and energy were at one time compressed into a single microscopic point. This point then exploded outward in all directions in a rapid expansion. The expansion has continued to the present day, which has allowed matter to cool to a state at which stable atomic components can form. The Big Bang theory proposes that our universe is finite in age, and since nothing can travel faster than the speed of light, there exists a cosmological horizon, which is the maximum distance light or energy could have travelled since the occurrence of the Big Bang. Since the universe is still expanding, however, regions of space that are visible from our vantage point are not within each other's cosmological horizons. For example, if galaxy A is 10 billion light years away from us, and galaxy B is 10 billion light years away from us in the opposite direction, there is a total distance of 20 billion light years between them. The universe has only existed long enough for light, energy, or information to travel 13.7 billion light years between them; thus, it is not possible for any contact to have been made between the two galaxies. Yet, even these vastly separated regions of space have been observed to be extremely homogeneous—they have remarkably similar features and properties despite being so far away from each other. The question, therefore, is what caused this apparent homogeneity observed in the universe. If matter rapidly expanded outward, why does the universe have such a uniform appearance in every direction? If the Big Bang theory is correct, some explanation for this horizon problem is needed.

Scientist 1

In the current state of the universe there exist regions that lie beyond the cosmological horizons of others, and therefore cannot possibly be influenced by them. This was not always the case. At a point in time mere microseconds after the Big Bang, all of the matter in the universe experienced a period of exponential expansion, known as inflation, before the rate of expansion fell to a more stable level. This inflation led to all regions of the universe having homogeneous features, even though they are not capable of affecting one another in any way in their current state.

Scientist 2

Although there is ample evidence that a Big Bang occurred, the horizon problem, as well as the flatness problem, suggest that the Big Bang is not the full story of the inception of the universe. The horizon problem can be solved if, instead of viewing the Big Bang as the "beginning of everything," we stipulate that the expansion seen after the Big Bang was already occurring for some time before the Big Bang occurred. This marks the Big Bang as a sort of "causal horizon," which disallows us from directly observing evidence from any period beforehand. If we assume the universe is cyclic, the homogeneity of the universe is explained as the result of a continuous cycle of expansion and compression, which would naturally lead to a universe having uniform features.

Which of the following, if true, would undermine both scientists' positions?

Possible Answers:

A new study about background microwave radiation has found that the Big Bang must have been the initial event of our universe.

New evidence shows that the Big Bang actually occurred billions of years earlier than formerly thought.

New evidence shows that the oldest galaxies that can be measured from our vantage point are actually receding rather than moving toward us.

New cosmological data suggests that the rate of expansion since the Big Bang has been decelerating at a constant rate.

New evidence suggests that the universe has been slowly expanding outward at a constant rate for an indefinite amount of time.

Correct answer:

New evidence suggests that the universe has been slowly expanding outward at a constant rate for an indefinite amount of time.

Explanation:

Both scientists' theories depend on the event of the Big Bang instantiating some set of conditions in the universe. If the Big Bang did not occur, and the universe has been constantly expanding forever, then neither theory would make sense.

The other answer choices are either irrelevant or would only undermine one scientist's argument. Both scientists suggest that older galaxies may be receding due to universal expansion. Scientist 1 argues that the Big Bang was the initial event of the universe; this statement would only weaken Scientist 2's argument. Constant deceleration would deny the inflation period hypothesized by Scientist 1, but support Scientist 2. The exact moment of the Big Bang does not affect either scientist's argument.

Example Question #952 : Act Science

A rover on Mars tests the soil on the planet in Gale Crater. An instrument on the rover dectects steep spikes in methane levels in the soil within 60 days. Additionally, satellite measurements from the area detect unusual plumes of methane from this specific area, which scientists suggest may have once contained an ancient freshwater lake. Two different scientists discuss whether this evidence is conclusive of the existence of life on the planet. 

Scientist 1

This is the first evidence that organic life exists on Mars. On Earth, 95% of methane gas is produced by microbial organisms, which points towards the presence of similar biological processes on Mars. The rover has also found evidence of water bound to soil in the crater, and pictures showing carvings in the sides of the crater walls suggest the existence of once-flowing water. Because this water could have supported life in the crater, this methane originated from a bacterial source and shows there is life on the planet.

Scientist 2

There is no evidence of life on Mars. These methane spikes came from organic matter left behind from recent meteor impacts as they degraded in the sun's rays. Although the crater was once filled with water, now all water is bound to minerals in the soil and it not accessible. Methane has also been measured on planets such as Saturn, Uranus, and Neptune, which have conditions too hostile to support life. There is not even enough evidence to suggest that the original water in the crater could have supported life. 

Which of the following describes the phenomena to which the scientists attribute methane on Mars?

Possible Answers:

Scientist 1: Ancient water in the crater

Scientist 2: Microbial organisms

Scientist 1: Microbial organisms    

Scientist 2: Organic matter from meteor impacts degrading in the sun's rays

Scientist 1: Microbial organisms

Scientist 2: Ancient water in the crater

Scientist 1: Organic matter from meteor impacts degrading in the sun's rays

Scientist 2: Microbial organisms 

Correct answer:

Scientist 1: Microbial organisms    

Scientist 2: Organic matter from meteor impacts degrading in the sun's rays

Explanation:

Scientist 1 says that the methane comes from microbial organisms, which suggests that life exists on the planet. Scientist 2 says that life does not need to exist on a planet for it to have methane deposits and suggests that it comes from the sun's rays degrading organic matter left from meteor impacts. 

Example Question #953 : Act Science

A rover on Mars tests the soil on the planet in Gale Crater. An instrument on the rover dectects steep spikes in methane levels in the soil within 60 days. Additionally, satellite measurements from the area detect unusual plumes of methane from this specific area, which scientists suggest may have once contained an ancient freshwater lake. Two different scientists discuss whether this evidence is conclusive of the existence of life on the planet. 

Scientist 1

This is the first evidence that organic life exists on Mars. On Earth, 95% of methane gas is produced by microbial organisms, which points towards the presence of similar biological processes on Mars. The rover has also found evidence of water bound to soil in the crater, and pictures showing carvings in the sides of the crater walls suggest the existence of once-flowing water. Because this water could have supported life in the crater, this methane originated from a bacterial source and shows there is life on the planet.

Scientist 2

There is no evidence of life on Mars. These methane spikes came from organic matter left behind from recent meteor impacts as they degraded in the sun's rays. Although the crater was once filled with water, now all water is bound to minerals in the soil and it not accessible. Methane has also been measured on planets such as Saturn, Uranus, and Neptune, which have conditions too hostile to support life. There is not even enough evidence to suggest that the original water in the crater could have supported life. 

According to the information given, upon which of the following points would both scientists agree?

Possible Answers:

Microbial organisms existed on the meteor that created Gale crater.

There is enough evidence to support the existence of water once on Mars.

The water in Gale crater could once have habited life.

Methane does always point to the existence of life.

Correct answer:

There is enough evidence to support the existence of water once on Mars.

Explanation:

Both scientists support the existence of water in the crater in the past. However, Scientist 2 disputes that this could have harbored life and does not agree with Scientist's 1 claim that methane more than likely suggests the existence of biological processes. Neither scientist suggests that organic matter on the meteor came from microbial organisms.

Example Question #11 : How To Find Conflicting Viewpoints In Earth And Space Sciences

A rover on Mars tests the soil on the planet in Gale Crater. An instrument on the rover dectects steep spikes in methane levels in the soil within 60 days. Additionally, satellite measurements from the area detect unusual plumes of methane from this specific area, which scientists suggest may have once contained an ancient freshwater lake. Two different scientists discuss whether this evidence is conclusive of the existence of life on the planet. 

Scientist 1

This is the first evidence that organic life exists on Mars. On Earth, 95% of methane gas is produced by microbial organisms, which points towards the presence of similar biological processes on Mars. The rover has also found evidence of water bound to soil in the crater, and pictures showing carvings in the sides of the crater walls suggest the existence of once-flowing water. Because this water could have supported life in the crater, this methane originated from a bacterial source and shows there is life on the planet.

Scientist 2

There is no evidence of life on Mars. These methane spikes came from organic matter left behind from recent meteor impacts as they degraded in the sun's rays. Although the crater was once filled with water, now all water is bound to minerals in the soil and it not accessible. Methane has also been measured on planets such as Saturn, Uranus, and Neptune, which have conditions too hostile to support life. There is not even enough evidence to suggest that the original water in the crater could have supported life. 

Which of the conditions in Gale crater would Scientist 1 support but Scientist 2 not support?

Possible Answers:

Organic matter from the meteor impact is still present in the soil. 

There is water not bound to the soil. 

Water in the Martian soil can still support life.

Gale crater was formed by a meteor impact.

Correct answer:

Water in the Martian soil can still support life.

Explanation:

Only Scientist 1 mentions the water in the soil supporting life, while Scientist 2 suggests that it is not accessible. Scientist 1 never mentions there presently being water present apart from the soil or there being organic matter from the meteor in the soil. Both would support the claim that the crater was formed by a meteor.

Example Question #955 : Act Science

A rover on Mars tests the soil on the planet in Gale Crater. An instrument on the rover dectects steep spikes in methane levels in the soil within 60 days. Additionally, satellite measurements from the area detect unusual plumes of methane from this specific area, which scientists suggest may have once contained an ancient freshwater lake. Two different scientists discuss whether this evidence is conclusive of the existence of life on the planet. 

Scientist 1

This is the first evidence that organic life exists on Mars. On Earth, 95% of methane gas is produced by microbial organisms, which points towards the presence of similar biological processes on Mars. The rover has also found evidence of water bound to soil in the crater, and pictures showing carvings in the sides of the crater walls suggest the existence of once-flowing water. Because this water could have supported life in the crater, this methane originated from a bacterial source and shows there is life on the planet.

Scientist 2

There is no evidence of life on Mars. These methane spikes came from organic matter left behind from recent meteor impacts as they degraded in the sun's rays. Although the crater was once filled with water, now all water is bound to minerals in the soil and it not accessible. Methane has also been measured on planets such as Saturn, Uranus, and Neptune, which have conditions too hostile to support life. There is not even enough evidence to suggest that the original water in the crater could have supported life. 

Which of the following discoveries would support the claims of Scientist 2?

Possible Answers:

Seismographs on the rover suggesting recent meteor impacts around Gale crater

Recent volcanic activity under the surface of Mars

The rover finding remains from the meteor that created Gale crater

Evidence of accessible water

Correct answer:

Seismographs on the rover suggesting recent meteor impacts around Gale crater

Explanation:

Only the seismographs showing recent meteor imapcts would support Scientist 2's theory that the methane came from organic matter from meteors degrading in rays from the sun

Example Question #956 : Act Science

A rover on Mars tests the soil on the planet in Gale Crater. An instrument on the rover dectects steep spikes in methane levels in the soil within 60 days. Additionally, satellite measurements from the area detect unusual plumes of methane from this specific area, which scientists suggest may have once contained an ancient freshwater lake. Two different scientists discuss whether this evidence is conclusive of the existence of life on the planet. 

Scientist 1

This is the first evidence that organic life exists on Mars. On Earth, 95% of methane gas is produced by microbial organisms, which points towards the presence of similar biological processes on Mars. The rover has also found evidence of water bound to soil in the crater, and pictures showing carvings in the sides of the crater walls suggest the existence of once-flowing water. Because this water could have supported life in the crater, this methane originated from a bacterial source and shows there is life on the planet.

Scientist 2

There is no evidence of life on Mars. These methane spikes came from organic matter left behind from recent meteor impacts as they degraded in the sun's rays. Although the crater was once filled with water, now all water is bound to minerals in the soil and it not accessible. Methane has also been measured on planets such as Saturn, Uranus, and Neptune, which have conditions too hostile to support life. There is not even enough evidence to suggest that the original water in the crater could have supported life. 

In the paragraph concerning Scientist 1's opinion, he or she uses evidence of water having existed on Mars in the past to support the existence of life on Mars. How does Scientist 2 disagree with this?

Possible Answers:

The water that may have existed on Mars in the past came from remnants of the meteor impact. 

The water that may have existed on Mars in the past has not been shown to be suitable for life.

There is no evidence of water ever having existed on Mars.

The existing water on Mars is bound to the soil.

Correct answer:

The water that may have existed on Mars in the past has not been shown to be suitable for life.

Explanation:

Scientist 2 says that water may not have been suitable for life even though it existed. He does not say that this is from the meteor impact. He says that the water is bound to minerals, not the soil itself. 

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