Science teacher: In any nation, a flourishing national scientific community is essential to a successful economy. For such a community to flourish requires that many young people become excited enough about science that they resolve to become professional scientists. Good communication between scientists and the public is necessary to spark that excitement.

Summary

If a nation has a successful economy, it must have a flourishing national scientific community. If the nation has a flourishing national community, it needs to have many young people who are excited enough about science to want to become scientists. If this excitement exists, there must be good communication between scientists and the public.

Strongly Supported Conclusions

Successful economy -> flourishing scientific community -> young people excited - > good communication between scientists and the public.

You can make any valid inference along this chain.

A
If scientists communicate with the public, many young people will become excited enough about science to resolve to become professional scientists.

Scientists communicating with the public is not a sufficient condition that can trigger any valid inferences. If you got this wrong, practice conditional indicators, mapping, and following lawgic chains.

B
The extent to which a national scientific community flourishes depends principally on the number of young people who become excited enough about science to resolve to become professional scientists.

While young people's excitement about science is necessary for a national scientific community to flourish, there is no evidence that *the number* of these students is principally important.

C
No nation can have a successful economy unless at some point scientists have communicated well with the public.

This is supported because it is a valid inference on the formal logic chain (Successful economy -> good communication). If you struggled to map this, practice mapping with two conditional indicators.

D
It is essential to any nation’s economy that most of the young people in that nation who are excited about science become professional scientists.

This is too strong to support. The stimulus only says that many young people need to be excited about science, not “most.”

E
An essential component of success in any scientific endeavor is good communication between the scientists involved in that endeavor and the public.

This is not supported because the stimulus never gives conditions for the success of any scientific endeavor.


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Zoologist: In the Lake Champlain area, as the North American snowshoe hare population grows, so do the populations of its predators. As predator numbers increase, the hares seek food in more heavily forested areas, which contain less food, and so the hare population declines. Predator populations thus decline, the hare population starts to increase, and the cycle begins again. Yet these facts alone cannot explain why populations of snowshoe hares everywhere behave simultaneously in this cyclical way. Since the hare population cycle is well correlated with the regular cycle of sunspot activity, that activity is probably a causal factor as well.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that susnpot activity is probably a causal factor in the size of hare populations. This is because the hare population cycle between larger and smaller sizes is correlated with the regular cycle of sunspot activity.

Notable Assumptions
The author assumes that the correlation between sunspot activity and hare population cycles isn’t just coincidence.

A
Reproduction in predator populations increases when sunspot activity indirectly affects hormonal processes associated with reproduction.
This strengthens by providing a potential causal mechanism between sunspots and hare populations. The sunspots might affect predator populations, and the predator populations would in turn affect hare populations.
B
Local weather patterns that can affect species’ population changes can occur both in the presence of sunspot activity and in its absence.
This doesn’t strengthen because it doesn’t provide any reason to think the sunspot activity has any causal relationship with hare populations. We have no reason to think these weather patterns are correlated with sunspots.
C
Brighter light during sunspot activity subtly but significantly improves the ability of predators to detect and capture hares.
This strengthens by providing a causal mechanism between sunspots and hare populations. The sunspots can affect predator ability to hunt, which in turn affects hare populations.
D
The variation from cycle to cycle in the magnitude of the highs and lows in snowshoe hare populations is highly correlated with variations from cycle to cycle in the intensity of highs and lows in sunspot activity.
This strengthens by strengthening the correlation between sunspots and hare populations. Not only are these two things generally correlated, but (D) now tells us that the specific degree of population increase/decrease is correlated with the degree of sunspot intensity.
E
Sunspot activity is correlated with increases and decreases in the nutritional value of vegetation eaten by the hares.
This strengthens by providing a potential causal mechanism. Sunspots may have an effect on the nutritional value of vegetation, which in turn can affect hare populations that eat the vegetation.

13 comments

Several three-year-olds who had learned to count to ten were trying to learn their telephone numbers. Although each child was familiar with the names of all the digits, no child could remember his or her phone number. Their teacher then taught each child a song whose lyrics contained his or her phone number. By the end of the day the children could remember their telephone numbers.

Summary
A group of 3-year-olds who new the numbers 1 through 10 were trying to learn their phone numbers. Initially no child could remember his or her number. But after a teacher taught each child a song that contained his or her phone number, the children could remember the phone number.

Strongly Supported Conclusions
The song the teacher taught probably helped each child remember his or her number.
A string of numbers might be easier to remember if they are part of a song.

A
There are some things that children cannot learn without the aid of songs.
Unsupported. Although the song likely helped the children remember their numbers, that doesn’t mean the song was required in order for them to remember. Maybe the children also could have remembered the numbers through a special game or special cartoon.
B
Familiarity with a concept is not always sufficient for knowing the words used to express it.
Unsupported. The children knew the numbers 1 through 10. There’s no evidence that they didn’t know the words to express these numbers. They had trouble remembering a specific string of numbers; not with the words that express those numbers.
C
Mnemonic devices such as songs are better than any other method for memorizing numbers.
Unsupported. The song likely helped them remember their phone numbers. But we don’t get a comparison to other memory methods. Maybe seeing the number in a special cartoon would have been more effective.
D
Children can learn to count without understanding the meaning of numbers.
Unsupported. Failing to remember a string of numbers does not imply inability to understand the meaning of numbers. We don’t have any evidence the children didn’t understand the meaning of “three.” They just had trouble remembering the order of several numbers put together.
E
Songs are useful in helping children remember the order in which familiar words occur.
Strongly supported. Children were familiar with individual numbers, but had trouble remembering a string of numbers. They were able to remember the string after learning a song containing that string of numbers. Doesn’t guarantee causation, but it is evidence the song helped.

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Consumer advocate: Even if one can of fruit or vegetables weighs more than another, the heavier can does not necessarily contain more food. Canned fruits and vegetables are typically packed in water, which can make up more than half the total weight of the can’s contents. And nothing stops unscrupulous canning companies from including more water per can than others include.

Summarize Argument
Heavier cans of fruit or vegetables from different companies may not actually contain more food. Some cans might have less food despite being heavier because the fruits and vegetables are packed in water, which can make up more than half the weight. Since some canning companies might add more water than others, heavier cans might not contain more food.

Identify Conclusion
The conclusion is the consumer advocate’s warning that heavier cans of fruit or vegetables may not actually contain more food.

A
The heavier of two cans of fruit or vegetables does not necessarily contain more food than the lighter of the two cans contains.
This accurately states the consumer advocate's main conclusion. Since packing companies can add more water to their cans, a heavier can of fruit or vegetables doesn’t always have more food than a lighter one. The heavier can might just have much more water than the lighter can.
B
The weight of the water in a can of fruit or vegetables can be more than half the total weight of the can’s contents.
This is a premise. The statement that water can make up more than half the weight of a can of fruit or vegetables helps readers understand the consumer advocate's conclusion that heavier cans don't always contain more food—they might just have more water.
C
Nothing stops unscrupulous canning companies from including more water per can than others include.
This is a premise. The claim that "nothing stops unscrupulous canning companies from including more water per can" supports the consumer advocate's conclusion that heavier cans do not always contain more food. The extra weight could just be from more water, not more food.
D
Some canning companies include less food in cans of a given weight than others include.
This is a necessary assumption of the consumer advocate’s argument. The advocate assumes that some canning companies might add more water and, therefore, less food to their cans. If this assumption is true, then a heavier can could have less food than another can of the same weight.
E
The heavier of two cans of fruits or vegetables may include more water than the lighter of the two cans contains.
This is a necessary assumption of the consumer advocate’s argument. The argument relies on the assumption that a heavier can may include more water—and therefore less food—than a lighter can. If this is true, then a heavier can doesn’t necessarily contain more food.

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John of Worcester, an English monk, recorded the sighting, on December 8, 1128, of two unusually large sunspots. Five days later a brilliant aurora borealis (northern lights) was observed in southern Korea. Sunspot activity is typically followed by the appearance of an aurora borealis, after a span of time that averages five days. Thus, the Korean sighting helps to confirm John of Worcester’s sighting.

Summarize Argument
The author concludes that the Korean sighting of the aurora borealis 5 days after John’s reported sighting of unusually large sunspots helps to confirm his reported observation. This is because sunspot activity is typically followed by the appearance of an aurora borealis after a time that average five days.

Notable Assumptions
The author assumes that the observed aurora borealis did not appear as a result of phenomena unconnected to sunspot activity. This overlooks the possibility that many other phenomena could give rise to an aurora borealis, which could account for the Korean sighting of the aurora borealis.

A
An aurora borealis can sometimes occur even when there has been no significant sunspot activity in the previous week.
If anything, this undermines the argument by suggesting the aurora borealis may have occurred without any sunspot activity occurring five days before it.
B
Chinese sources recorded the sighting of sunspots more than 1000 years before John of Worcester did.
This simply indicates that sunspots have occurred for many years. But it doesn’t help confirm John’s reported sighting of sunspots or connect the aurora borealis with confirmation of John’s sighting.
C
Only heavy sunspot activity could have resulted in an aurora borealis viewable at a latitude as low as that of Korea.
This strengthens by eliminating other potential causes of the aurora borealis. Only sunspot activity could have created an aurora borealis viewable in Korea, so there must have been sunspot activity before the Korean sighting.
D
Because it is impossible to view sunspots with the naked eye under typical daylight conditions, the sighting recorded by John of Worcester would have taken place under unusual weather conditions such as fog or thin clouds.
This has no clear impact on John’s sighting. This simply gives more details about when his sighting would have occurred.
E
John of Worcester’s account included a drawing of the sunspots, which could be the earliest illustration of sunspot activity.
The fact John drew sunspots doesn’t help connect the Korean sighting of aurora borealis with John’s sighting of sunspots. What do drawings have to do with the aurora borealis? Nothing.

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