ACT Science : Earth and Space Sciences

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #141 : Earth And Space Sciences

A scientist is studying the makeup of a crossection of the ground on a plot of land on the Pacific coast. The cross-section is as follows:

 Layers

The line noted by the X marks earth that was on the surface approximately 20,000 years ago. The law of superposition states that, in cross-sections of the Earth's crust, layers that are closer to the center of the Earth are older than those that are farther away. 

Which layer(s) are older than 20,000 years?

Possible Answers:

Layers A, B, C, D, and E

Layer E only

Layer D only

Layer A only

Layer E and Layer D

Correct answer:

Layer E only

Explanation:

The correct answer is Layer E. It may be tempting to add Layer D to this answer. However, since Layer D also intersects with other layers, we cannot say with certainty that it is older than 20,000 years based on the law of superposition.

Example Question #142 : Earth And Space Sciences

A scientist is studying the makeup of a crossection of the ground on a plot of land on the Pacific coast. The cross-section is as follows:

 Layers

The line noted by the X marks earth that was on the surface approximately 20,000 years ago. The law of superposition states that, in cross-sections of the Earth's crust, layers that are closer to the center of the Earth are older than those that are farther away. 

A sample is taken from point P and is analyzed. It is determined that the stone found at point P was at the surface of the Earth only 10,000 years ago. What conclusion can the scientist draw based on this information?

Possible Answers:

Layer D really belongs near Layer E and at some point the stone in Layer D was pushed upwards

None of these

Layer D really belongs near layer B and at some point the stone in Layer D was pushed downward

Layer D is equivalent to Layer B

This is an exception to the law of superposition

Correct answer:

Layer D really belongs near layer B and at some point the stone in Layer D was pushed downward

Explanation:

The correct answer is the one that includes Layer D's apparent misplacement farther down into the Earth than it should be. Since it has been dated at around 10,000 years old, we know that its presence below line X does not indicate that it is indeed older than 20,000 years old. 

Example Question #142 : Earth And Space Sciences

A scientist is studying the makeup of a crossection of the ground on a plot of land on the Pacific coast. The cross-section is as follows:

 Layers

The line noted by the X marks earth that was on the surface approximately 20,000 years ago. The law of superposition states that, in cross-sections of the Earth's crust, layers that are closer to the center of the Earth are older than those that are farther away. 

An archaeologist hypothesizes that early humans inhabited this coastal region around 22,000 years ago. In which layer is the archaeologist most likely to find evidence to support his hypothesis?

Possible Answers:

Layer A

Layer D

Layer E

Layer C

Layer B

Correct answer:

Layer E

Explanation:

The correct answer is Layer E. Layer E is the only layer that is below the line marked at 20,000 years old. Therefore, we can infer that, if in any of these layers lies evidence to support his hypothesis, it must be in Layer E.

Example Question #143 : Earth And Space Sciences

One night there was a meteor shower and scientists in four different regions, A, B, C and D, observed and counted the number of meteors seen. The scientists noted the duration of the meteor shower and the visibility of the stars. 

Act 2

How does the visibility of the night sky impact the number of meteors observed? 

Possible Answers:

The less clear the stars, the more meteors were seen

Intermediate visibility yields the highest number of meteors seen

There is no relationship

The more clear the stars, the less meteors were seen

The better the visibility of the stars led to a higher number of meteors seen

Correct answer:

The better the visibility of the stars led to a higher number of meteors seen

Explanation:

Regions A and B saw more meteors than the other regions. These two regions also had the be visibility of the night sky. Region C had no visibility of the night sky and saw no meteors. Region C could somewhat see the night sky and saw the second lowest number of meteors. This means as the visibility increased so did the number of meteors seen. 

Example Question #141 : Earth And Space Sciences

Explorers have discovered a new planet, Planet K. It is known that Planet K has magnetic poles to similar to those of Earth, so the explorers decide that using a compass to navigate is possible. When navigating Planet K's surface, it is discovered that the compass points north for a distance then flips so that it points north in the opposite direction for a distance, before returning to pointing north in the original direction. It is known that the magnetic poles of the planet flip every 100 years. Weather is recorded on the planet for 250 years. 

Capture 2

Why does the explorer's compass flip the north pole depending upon distance traveled? 

Possible Answers:

The planet does not have magnetic poles 

Cannot be determined from the given information

The poles are switching directions as the explorers move

The rocks below the explorers were formed during different time periods giving the rocks different magnetic directions

The planet's magnetic field does not interact with the compass

Correct answer:

The rocks below the explorers were formed during different time periods giving the rocks different magnetic directions

Explanation:

It is known that Planet K has magnetic poles similar to those of Earth so both the planet does not have magnetic poles and that the magnetic field of the planet does not affect the compass are incorrect answers. It is stated that the magnetic poles flip every 100 years, but there is nothing stated that the magnetic poles are currently switching and this would not cause the phenomenon seen by the explorers. It is possible that the rocks below the explorers are magnetic and were formed when the poles were in one orientation and then flipped into the other orientation. This would cause the rocks to have different magnetic orientations and affect the explorer's compass. 

Example Question #1081 : Act Science

Scientist 1: This scientist asserts that drilling for oil should be performed in the ocean. Scientist 1 claims that in the ocean, the oil is at a shorter depth below the Earth’s surface than on dry land. The shorter drilling depth is more ideal for access by drills.

Scientist 2: Scientist 2 believes that drilling for oil should be performed on dry land and not underwater. This is due to the fact that water is at a higher pressure than is observed on the surface of Earth. Scientist 2 asserts that drilling at the lower pressure will be less likely to damage the equipment resulting in an unsuccessful event.

Experiment: The scientists conduct various experiments. The data that the scientists collect indicates the depth at which it is necessary to drill on land and in the ocean in order to reach. The other data that the scientist collect is on the pressure that the equipment will need to experience while drilling for oil at each location.

If a third option was present for drilling on a coastal region that allows for the short drilling depth and for drilling to be done on land, which scientist would support drilling at this location?

Possible Answers:

Cannot be determined from the given information 

Scientist 1, since the drilling is performed on land

Scientist 2, since the drilling depth is short

Neither scientist would want to drill here because it is a non-ideal loaction

Both of the scientist would want to drill here, since it combines the benefits of both locations

Correct answer:

Both of the scientist would want to drill here, since it combines the benefits of both locations

Explanation:

This coastal location removes the issue of water pressure, while keeping the short drilling distance that would be the benefit of drilling underwater. Both scientists would want to drill at this location because it contains the benefits that both of the scientists prefer.  

Example Question #144 : Earth And Space Sciences

Scientist 1: Scientist 1 claims that the best spot to find gold is near volcanic areas. This scientist claims that the high temperatures and high pressure helps to form the gold. Therefore the best area to find large quantities of gold is near volcanoes.

Scientist 2: Scientist 2 asserts that the best area to find gold is in rivers. In the rivers the gold can be free flowing and easier to see. In addition, the gold found in the rivers does not necessarily require equipment for digging. It is is found in the river due to the water carrying, rather than eroding it. 

What is not taken into account by Scientist 1? 

Possible Answers:

Potential volcanic activity

The amount of gold that can be found

The rarity of volcanoes 

All of these

The quality of the gold

Correct answer:

All of these

Explanation:

Scientist 1 wants to look for gold near volcanic areas, which may requiring some digging. This can be dangerous as digging may impact the stability of the volcano and cause an eruption that will harm the workers. Also, volcanoes can be hard to find, depending on what transportation resources are available, and the quality of gold is not considered in Scientist 1's argument.

Example Question #142 : Earth And Space Sciences

Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.

Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.

In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.

Sample #

Water Ice?

Concentration of Organics

1

No

N/A

2

Yes

1 mg/L

3

No

N/A

4

Yes

4 mg/L

5

Yes

10 mg/L

These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.

Sample #

Water Ice?

Concentration of Organics

1

No

N/A

2

No

N/A

3

No

N/A

4

No

N/A

5

Yes

1 mg/L

The data presented in the passage most closely support the idea that:

Possible Answers:

organic molecules occur only on Earth.

organic molecules are probably not widespread in the universe.

organic molecules on Earth may have been seeded by comets.

organic molecules were only seeded by comets if the comets themselves harbor microbial life.

Correct answer:

organic molecules on Earth may have been seeded by comets.

Explanation:

The observation of greater concentrations of organics on the comet as compared to Mars suggests that comets at least have the potential to have seeded organic molecules on the eartly Earth.

Example Question #145 : Earth And Space Sciences

The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.

Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand.  The Big Bang Theory is now the prevalent theory for the origin of the universe.

The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.

Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.  

The Big Bang Theory states:

Possible Answers:

The universe was created by the cooling of a hot, high energy mass

All of the other choices

The universe is always expanding

The big bang produced gases with a lighter mass than those found on Earth

Correct answer:

All of the other choices

Explanation:

The Big Bang Theory states that the universe containing mass was created around 14 billion years ago when the universe was in a hot, dense state that was full of energy. The universe was cooling and expanding resulting in the creation of atoms (and mass). The first gases created contained elements that are smaller than those found on earth. The universe continues to expand.

Example Question #145 : Earth And Space Sciences

The chart below depicts the average rainfall by location on the Earth.  Zero degrees latitude corresponds to the equator.  Positive latitudes are north of the equator, while negative latitudes are south of the equator.  A latitude with a magnitude of 90 degrees correlates with one of Earth's poles.  

Rainfall

Which best describes the rainfall trend between thirty and sixty degrees latitude?

Possible Answers:

Rainfall decreases as latitude increases

Rainfall is approximately equal for these latitudes

None of these

Rainfall increases as latitude increases

Correct answer:

Rainfall is approximately equal for these latitudes

Explanation:

Examining the curve of the graph between 20 and 60 degrees, we see that, even though there is slight variation, rainfall hovers around 30 inches.  Therefore, we can conclude that these latitudes experiences equal approximate rainfall.  

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