ACT Science : How to find experimental design in earth and space sciences

Study concepts, example questions & explanations for ACT Science

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Example Question #1 : How To Find Experimental Design In Earth And Space Sciences

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.

What new evidence would support the argument made by Scientist 1?

Possible Answers:

An experiment suggesting the ocean acidity level has an impact on the atmospheric temperature changes

An experiment suggesting the ocean acidity level fluctuates with atmospheric temperature changes

An experiment suggesting that 13% of CO2 remaining in the atmosphere is the isotopic CO2 caused by humans

Evidence showing that use of fossil fuels directly increases the temperature
Evidence showing the release of natural CO2 from carbon sinks directly increases the temperature
Correct answer:
Evidence showing that use of fossil fuels directly increases the temperature
Explanation:

Scientist 1 states that "Global warming is caused by increases in atmospheric CO2, which is directly created by humans and their consumption of fossil fuels." An experiment showing that use of fossil fuels directly increases the temperature would support the beliefs of Scientist 1. Scientist 1 does not discuss ocean acidity in his argument, therefore the reader cannot assume any information on this topic would support the argument of Scientist 1.

Example Question #2 : How To Find Experimental Design In Earth And Space Sciences

A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.

 

 

Hubble_graph

Which of the following is the correct unit for proper distance in this experiment?

Possible Answers:

Meter

Megaparsec

Mile

Kilometer

Correct answer:

Megaparsec

Explanation:

Notice that on the graph, the x-axis (the proper distance) is measured in megaparsecs.

Example Question #3 : How To Find Experimental Design In Earth And Space Sciences

A scientist observes the motion of stars, planets, and other objects in deep space through a high-powered telescope. She observes that these objects all appear to be moving away from the Earth and graphs her results comparing their velocities, in kilometers per second, and their proper distance, in megaparsecs.

 

 

Hubble_graph

Which of the following would be necessary to recreate the experiment?

Possible Answers:

A satellite taking pictures of the distant stars from another location.

A high-powered telescope.

Infrared imaging of distant stars.

A very high mountain to place the telescope on top of.

Correct answer:

A high-powered telescope.

Explanation:

While many of these suggestions would certainly make the experiment easier, the only necessary piece of equipment, as stated in the set up of the experiment, is a high-powered telescope.

Example Question #4 : How To Find Experimental Design In 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

Which of the following would most directly undermine the major finding of this study?

Possible Answers:

Another location on the comet is found to have almost identical concentrations of organic molecules as the original site in this study

The detection equipment on the comet was contaminated with organic molecules from Earth

Another location on Mars is found to have lower levels of organic molecules

Another location on the comet is found to have higher concentrations of organic molecules

The detection equipment on the comet has a higher threshold for detecting organic molecules than the one on Mars

Correct answer:

The detection equipment on the comet was contaminated with organic molecules from Earth

Explanation:

The major message of the study depends on the observation that the comet has a higher concentration of organics than does Martian soil. As a result, if the detection equipment was contaminated, the measured organic molecules were actually brought to the comet from Earth.

Example Question #5 : How To Find Experimental Design In 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

Before sending the probe into space, scientists suggested that organics may be found on celestial bodies like comets.  This suggestion, made in the absence of direct evidence, is most nearly:

Possible Answers:

A theory

A conclusion

Both a theory and a law

A hypothesis

A law

Correct answer:

A hypothesis

Explanation:

Before sending the probe, the scientists had no direct evidence to generate a mature scientific theory.  The passage indicates that the scientists hoped to use the data to mature their hypotheses that organics may exist in space, thus making the statement in the question best characterized as a hypothesis.

Example Question #6 : How To Find Experimental Design In 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 use of multiple samples on both the comet and Mars is most likely used to

I.  Compare different geographical regions on both the comet and Mars, as measured for the concentration of organics

II.  Help determine the consistency of measurements taken by the instruments

III.  Ascertain how depth of sampling impacts the concentration of organics

Possible Answers:

II and III

I and III

II only

I and II

I only

Correct answer:

II and III

Explanation:

The passage specifies that the sampling is being completed in one location on both Mars and the comet.  Thus, option I is not appropriate.  Both II and III are valid reasons for using multiple measurements.  These multiple measurements give us an idea of how consistent our measurement instruments are, as well as the overall trends that we are observing.

Example Question #7 : How To Find Experimental Design In 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

After collecting the data, scientists involved in the study expressed their desire to repeat sampling on another comet.  Based only on the data in the passage, which of the following would suggest that organics would not be present?

I.  No water ice present in the comet

II.  The comet has no composition similarities to Earth

III.  The comet has no composition similarities to Mars

Possible Answers:

I only

III only

II and III

I and II

II only

Correct answer:

I only

Explanation:

I is the best answer here because the data in both tables suggest that no organics are found when there is no water in which they can be dissolved.  The composition similarity to Earth or Mars is less relevant, as no part of the passage suggests this has a bearing on the relative abundance of organics.

Example Question #8 : How To Find Experimental Design In Earth And Space Sciences

Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.

Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.

Pollen_table_1

Pollen_table_2

In order to replicate the above study, which of the following must be known?

Possible Answers:

The location and depth from which each sample was taken

The average precipitation over the year in which the samples were taken

The time of year the samples were taken

The total number of spores in each sample

Correct answer:

The location and depth from which each sample was taken

Explanation:

The scientists were only concerned with temperature and precipitation as they related to the ideal climate for each plant type. As such, the climate at the time of sample collection is not important. The total number of spores in each sample is also unnecessary information. Total spore count may vary across samples; scientists were more concerned with the percent of the sample for which each plant spore accounted. The locations and depths of each sample are important because each sample represents a particular place and time. Because climate is dependent on location, it is important to sample from the same place in order to replicate the study's results.

Example Question #9 : How To Find Experimental Design In Earth And Space Sciences

Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.

Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.

Pollen_table_1

Pollen_table_2

In Table 2, what is the most likely explanation for the varying concentrations of spores from Plant 1 across each sample? 

Possible Answers:

Spores are randomly distributed by the wind, so spore count will naturally vary across each sample.

There is no significant difference in spore concentration across each sample.

The older the sample, the fewer the spores that are able to survive intact.

Plant A is currently extinct.

Each sample represents the vegetative distribution from a different period of time.

Correct answer:

Each sample represents the vegetative distribution from a different period of time.

Explanation:

According to the passage, prominent vegetation can indicate the climate in a region over a given time period. Because a plant's prominence can be linked to the climate at that time, the change in spore concentration most likely indicates a change in climate. Climate, by definition, consists of patterns that occur over long periods of time. Therefore, changes in spore concentration are most likely tied to the different eras that each sample is taken from. This is further evidenced by the scientists' decision to take samples from different depths of the lake bed.

Example Question #9 : How To Find Experimental Design In Earth And Space Sciences

Scientists studying historical trends in climate change have a number of tools at their disposal. One method of analyzing paleoclimate data involves the use of fossilized pollen spores embedded in sediment. Pollen spores are specific to the plant that produced them. Because the spores are resilient and are widely-distributed by wind, they provide a snapshot of the vegetation that was widespread at a particular point in time. By identifying the age of a sample and the composition of the various spores, scientists can identify the prominent vegetation and use this information to gain insight into the climate at the time the spores were deposited.

Scientists took sediment samples from various depths of a lakebed. They found that five types of pollen spores make up the majority of spore deposits in each sample. In Table 1, plants are listed along with the respective temperature ranges and levels of precipitation for the areas in which they are commonly found. Table 2 shows the composition of the assortment of spores in each of the four samples taken by the scientists.

Pollen_table_1

Pollen_table_2

In Table 1, what does the range "8 - 15" represent with respect to Plant E?

Possible Answers:

The average number of spores from Plant E found in each sample.

The temperature in degrees Celsius at which Plant E thrives.

The depth at which the majority of Plant E spores were found.

The average annual precipitation required for Plant E to thrive.

The temperature in degrees Celsius at which Plant E is unable to survive.

Correct answer:

The temperature in degrees Celsius at which Plant E thrives.

Explanation:

In Table 1, the range "8 - 15" can be found in the middle column. 

Screenshot_2015-02-16_at_10.13.28_pm

The data label for this column indicates that the range is a measure of temperature in degrees Celsius. The information in the passage states that the temperatures shown are those in which a plant commonly may be found.

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