Answers and Explanations—4.9 Classroom Noise

P1	Paragraph 1	Comments
S1	It should come as no surprise to any teacher or parent that noise in a classroom environment is distracting and may impact a student’s ability to learn.	Classroom noise is distracting, of course.
2	But what types of noise are most distracting?	But what kinds? Other questions.
3	At what volume level does background noise begin to impact learning?
4	How severe is the problem?
5	Recent research can shed light on these important questions, and some of the results are surprising.	Research can shed light.

	The phrase “shed light on” in the passage is closest in meaning to	VOCABULARY. “Shed light on” = illuminate, clarify, make clear(er).
✗	A enflame	Once an issue has been made more clear, it might “enflame” (enrage or anger) people, but these words are not related.
✓	B clarify	Correct. “Recent research can shed light on these important questions” = research can clarify, or make clearer, these questions.
✗	C decide	Too extreme. “Shed light on” does not typically mean that these questions are fully decided or resolved by the research.
✗	D obscure	Opposite. To “obscure” something is to make it less clear or uncertain.

P2	Paragraph 2	Comments
S1	Perhaps the most consistent finding of the new research is the degree to which even low levels of noise can have a substantial impact on student performance.	Even low noise levels can impact student performance.
2	Noise levels are gauged in terms of a decibel scale—every increase of 10 decibels corresponds to a doubling of perceived loudness.	Decibel scale.
3	Adult conversation at a distance of 3 feet is roughly in the range of 55 to 65 decibels.
4	Ninety decibels is roughly the loudness achieved by a train whistle at a distance of 500 feet (about 152 meters) or a lawn mower at a distance of 25 feet (8 meters).
5	Both of these are certainly jarring enough to catch most people’s attention.
6	In fact, 90 decibels is the level at which hearing loss can begin, if people are exposed to it on a sustained basis.	90 decibels: hearing loss can begin.
7	Children are even more sensitive to loud sounds than adults.	Children are even more sensitive.
8	As a result, United States federal regulations mandate that all ambient classroom sounds above 90 decibels must be dampened; federal grants are made available for school districts to improve acoustics and soundproofing when these levels are exceeded.	So US regulations: classrooms must dampen sounds above 90 decibels. Grants to help.

	Which of the sentences below best expresses the essential information in the highlighted sentence in paragraph 2? Incorrect choices change the meaning in important ways or leave out essential information.	Simplify Sentence. S1 states that new research consistently finds that even low levels of noise can impact student performance in a classroom.
✗	A A consistent finding of the new research is that low levels of noise can affect student performance more than loud noise.	The sentence does not state or imply that low levels of background noise in a classroom have a bigger impact than high levels of noise.
✗	B Research on student performance strongly suggests that high levels of noise have the most substantial impact.	This version is plausible. But the original sentence makes a claim only about what happens with low levels of noise.
✓	C Even low levels of noise can seriously affect student performance, new research shows.	Correct. This choice says essentially the same thing as P2 S1 , but simplifies the language somewhat and reorders the wording.
✗	D Much new research claims that consistent levels of noise have a substantial impact on student performance.	This sentence changes the meaning in one very important way: it changes “even low levels” to “consistent levels.”

	It can be inferred from paragraph 2 that	Inference. The question does not narrow down what the inference is about. So the correct answer could be supported by facts anywhere in the paragraph.
✓	A operating a lawn mower without hearing protection can lead to hearing loss	Correct. S4 states that lawn mowers emit a noise of approximately 90 decibels at a distance of 25 feet. A person operating a lawn mower is much closer than that. S6 states that sustained exposure to sounds measuring 90 decibels can lead to hearing loss. You can infer that lawn mower operators without protection are at risk of hearing loss.
✗	B federal regulations controlling excessive classroom noise eliminate declines in student performance	S1 asserts that even low levels of classroom noise can hinder student performance. The paragraph later states that 90 decibels, the cutoff for federal regulations, is quite loud. So the regulations do not eliminate the problem of declines in performance.
✗	C adults are not generally capable of speaking at a loudness of 90 decibels	S3 states that adult conversation is approximately 55 to 65 decimals. But nothing in the paragraph suggests that adults cannot speak much more loudly than that.
✗	D children are unlikely to suffer permanent damage caused by excessive classroom noise	According to P2, sustained exposure to 90 decibels can lead to hearing loss in adults, and children are more sensitive to loud sounds than adults. So children are in fact likely to suffer permanent damage if they are regularly subjected to excessive classroom noise.

	The word “ambient” in the passage is closest in meaning to	VOCABULARY. “Ambient” = nearby, in the immediate environment or surroundings.
✗	A remote	Opposite. “Remote” = faraway or distant.
✓	B surrounding	Correct. “All ambient classroom sounds above 90 decibels must be dampened” = all surrounding classroom sounds, all sounds in the classroom’s environment, above this level must be dampened.
✗	C dissonant	This word has two fairly common meanings, but both are unrelated. “Dissonant” when used with sounds means that something is lacking harmony, while “dissonant” when used with colors (or other items) means unsuitable, unusual, or not matching/combining well.
✗	D constant	Close but not quite. An ambient sound might not be constant. It may fade in and out.

P3	Paragraph 3	Comments
S1	New research, however, indicates that learning issues begin at a much lower noise level.	But much lower noise levels can hurt learning.
2	Even barely detectable noise, such as whispering behind a student, noise from a neighboring classroom, or the turning on and off of electric equipment such as a heater, can be problematic.
3	These noises, while barely perceptible—at levels as low as 30 or 35 decibels—cause the cortisol level in many students to increase.
4	Cortisol is a hormone released in response to low blood sugar levels, waking up, and most importantly, stress.	Even really quiet noises can increase cortisol, a “stress hormone.”
5	The increase of this “stress hormone” produces difficulties with focus, can lead to physical exhaustion, and can impair the ability of a person to convert new information into long-term memory.	Cortisol can interfere with learning.
6	A 2013 study published in the Journal of Urban Health demonstrated that, after controlling for various other socioeconomic factors, among eight- and nine-year-old students a 10-decibel increase in background noise resulted in a predicted drop in test scores in both French and mathematics of about 5.5 percent.
7	Many other studies conducted since 1980 have had similar findings: noisier classroom environments lead to decreases in reading aptitude, cognitive thinking skills, language acquisition, and even physical coordination.	Studies have linked noise to learning problems.

	The word “problematic” in the passage is closest in meaning to	VOCABULARY. “Problematic” = challenging, difficult, causing problems.
✗	A simplistic	Somewhat opposite. “Simplistic” = too simple, oversimplified.
✗	B deceptive	Unrelated. “Deceptive” = misleading, false, or counterfeit.
✗	C quizzical	Thinking of solving a problem might make “quizzical” sound tempting, but these words are not related. “Quizzical” = inquiring or questioning, curious.
✓	D troublesome	Correct. “Even barely detectable noise… can be problematic” = even barely detectable noise can be troublesome, it can cause trouble or problems.

	According to paragraph 3, what is the relationship between cortisol and noise in the classroom?	Fact. S3 introduces the relevant link between cortisol and classroom noise.
✗	A Cortisol is a hormone produced upon waking and in times of stress.	S4 points out these facts about cortisol production. But this does not clarify the relationship between classroom noise and cortisol.
✗	B Cortisol can make classroom noises seem louder than they actually are.	Nothing in the paragraph suggests that higher levels of cortisol ever cause noises to seem louder than they actually are.
✓	C Even soft classroom noises can increase the production of cortisol.	Correct. S3: “These noises, while barely perceptible—at levels as low as 30 or 35 decibels—cause the cortisol level in many students to increase.”
✗	D Elevated levels of cortisol can impair memory and lead to exhaustion.	S5 points out these facts about the effects of high cortisol levels. But this does not clarify the relationship between classroom noise and cortisol.

	Why does the author mention “decreases in reading aptitude, cognitive thinking skills, language acquisition, and even physical coordination”?	Purpose. S7 lists these findings from research about the effects of classroom noise.
✗	A To restrict the known problems associated with excessive classroom noise to a specified list	S7 lists these problems as associated with noisy classroom environments. But nothing in the sentence or paragraph states or suggests that this list is complete. Other problems not mentioned may be known.
✗	B To assert that these problems are not so important within the context of broader issues facing many students	Nothing in the paragraph compares these classroom performance issues with other problems students may be facing.
✗	C To encourage teachers to take action to limit the extent of classroom noise	The author would likely agree that limiting the extent of classroom noise would be beneficial. But the purpose of this list, and the entire paragraph, is to describe the problem, not to appeal to anyone in particular to take action.
✓	D To illustrate the breadth of problems that studies have associated with noisy classrooms	Correct. The paragraph details problems caused by even low levels of classroom noise. This sentence outlines some specific, known problems associated with noisier classrooms.

P4	Paragraph 4	Comments
S1	Another interesting finding is that different types and levels of noise can have varying effects on different groups of children.	Different noises can have different effects on different children.
2	In a study conducted at the University of Southampton, England, differing levels of “white noise,” which sounds roughly like running water or hissing, were introduced into multiple classrooms.	Study on white noise.
3	The study found that students with a higher ability to focus were most affected by the white noise at any volume, while students with attention difficulties actually performed better with low to moderate levels of white noise.	Students who could focus well: most affected. Students with attention difficulties: actually improved at low levels of noise.
4	Researchers speculate that this is true because the noise forced the students with attention difficulties to exert more effort to overcome the background noise, thereby temporarily improving their level of focus.	Possible reason: these students had to exert more effort to overcome noise. That improved focus.

	The word “this” in the passage refers to	Reference. S4: “this is true because… ” What can be true or not? What is the author trying to explain with “because”?
✓	A what the study found	Correct. “This” refers back to what the study found. The rest of the sentence reveals that the author is specifically talking about the second finding (about students with attention difficulties). The author claims that this finding is true because of a particular reason outlined in S4.
✗	B the study itself	“This” refers to what the study found, not the study itself. It would be strange to call a research study “true.” You could call it accurate, revealing, etc., but the findings would be true.
✗	C the white noise	The white noise that affected the students is neither “true” nor untrue. Rather, the findings about the white noise’s effects are true.
✗	D how students with attention difficulties performed	How these students performed (that is, better with low levels of white noise) is not what “this” refers to. Their level of performance is neither “true” nor untrue.

	According to paragraph 4, an interesting finding from a research study conducted at the University of Southampton is that	Fact. S2 introduces this study. S3 lists its findings. S4 discusses a possible reason for one of its findings.
✗	A white noise had no impact on students in the class who could focus their attention well	S3: “The study found that students with a higher ability to focus were most affected by the white noise at any volume.”
✓	B some students improved their performance with moderate levels of white noise	Correct. S3: “The study found that… students with attention difficulties actually performed better with low to moderate levels of white noise.”
✗	C students in the class were affected roughly equally by different levels of white noise	S3 makes it clear that different groups of students were affected differently by the white noise.
✗	D students were more negatively affected by low levels of white noise than by higher levels	Nothing in the paragraph mentions that low levels of white noise had worse effects than higher levels.

P5	Paragraph 5	Comments
S1	Finally, increased noise can place undue burden on teachers.	Noise burdens teachers, too.
2	In order for a teacher to keep the attention of his or her students, they must speak about 15 to 20 decibels more loudly than any competing noise.
3	In addition, for every doubling of distance, the perceived loudness drops by about 6 decibels.
4	Thus, a student sitting 24 feet (about 8 meters) from a teacher will perceive reduced volume of about 12 decibels relative to a student sitting 6 feet (2 meters) away.
5	In a typical classroom, the teacher must speak as much as 30 decibels more loudly than any background noise.
6	If that background noise is high, teachers are forced to practically shout to be heard by students in the back of the classroom.	They have to shout over background noise.
7	Such a loud level of speaking for hours per day can lead to significant physical strain, high blood pressure, and, eventually, vocal-cord scarring.	Resulting problems.

	The word “undue” in the passage is closest in meaning to	VOCABULARY. “Undue” = extreme, unjustified, inappropriate.
✗	A invisible	Unrelated. “Invisible” = unable to be seen.
✓	B excessive	Correct. “Increased noise can place undue burden on teachers” = increased noise can place excessive, inappropriate burden on teachers.
✗	C moderate	Opposite. As an adjective (description), “moderate” = average or common. Be careful not to confuse this with the verb (action), “to moderate” = to control, calm, or lessen.
✗	D uncompensated	Too specific. “Uncompensated” = not paid for, so an uncompensated burden on a teacher would be undue or inappropriate. But not every undue burden is necessarily uncompensated.

	It can be inferred from paragraph 5 that if the distance between a noise and a person is halved, the perceived loudness will	Inference. S3 discusses the change in perceived loudness that accompanies change in distance.
✗	A decrease by about 12 decibels	This decline is mentioned in S4. But the situation in this question is different. In S4, the distance is quadrupled (multiplied by 4) to go from 6 feet to 24 feet. But in this question, the distance is halved.
✗	B decrease by about 6 decibels	This is the decline directly outlined in S3. However, this decline corresponds to a doubling of distance (multiplying by 2). But the question asks about a halving of distance (dividing by 2).
✓	C increase by about 6 decibels	Correct. Halving the distance between a noise and the person perceiving the noise is the opposite of doubling the distance. So it stands to reason that the change in perceived loudness should also be opposite. S3 says that if the distance is doubled, the perceived loudness declines by about 6 decibels. So if the distance is instead halved, you can infer that the perceived loudness increased by about 6 decibels. It’s the same comparison, just in reverse.
✗	D increase by about 12 decibels	This choice overstates the increase in perceived loudness.

	According to paragraph 5, why does background noise in the classroom increase the burden on teachers? To receive credit, you must select TWO answer choices.	Fact. P5 discusses the burden that background classroom noise places on teachers. Two reasons are given for this burden.
✓	a They must speak more loudly than any competing noise.	Correct. Discussed in S2.
✗	b Talking loudly tends to scar a teacher’s vocal cords immediately.	S7 states that teachers’ vocal cords can be scarred by talking loudly. However, S7 describes this effect as occurring “eventually” over a lengthy period, strongly suggesting that this scarring generally doesn’t happen “immediately” after one bout of loud talking.
✗	c Classroom noise gives uninterested students an excuse for not paying attention.	This idea is plausible. But it is not suggested anywhere in P5.
✓	d Teachers must project their voices even more to reach the back of the room.	Correct. S3–4 describe the drop in volume that happens over distance. This means that teachers have to speak that much more loudly to reach all their students (as much as 30 decibels more loudly, according to S5). Without much background noise, this extra projection would still be necessary. But it wouldn’t be as likely to put the teacher into a health danger zone. When this factor is combined with the need to talk above significant background noise, though, the teacher may wind up damaging his or her vocal cords or incurring other health issues.

P2	Paragraph 2	Comments
S1	Perhaps the most consistent finding of the new research is the degree to which even low levels of noise can have a substantial impact on student performance.
2–4	A Noise levels are gauged in terms of a decibel scale—every increase of 10 decibels corresponds to a doubling of perceived loudness. Adult conversation at a distance of 3 feet is roughly in the range of 55 to 65 decibels. Ninety decibels is roughly the loudness achieved by a train whistle at a distance of 500 feet (about 152 meters) or a lawn mower at a distance of 25 feet (8 meters).	Placing the new sentence here may work with the prior sentence, if the new research findings in S1 are the facts that “have caught the attention of the United States government.” However, S2 doesn’t follow up at all on the reference to the US government.
5–6	B Both of these are certainly jarring enough to catch most people’s attention. In fact, 90 decibels is the level at which hearing loss can begin, if people are exposed to it on a sustained basis.	Placement here leaves the phrase “both of these” in S5 without a logical reference point. Also, S5 has no follow-up on the US government.
7	C Children are even more sensitive to loud sounds than adults.	Placing the new sentence here breaks the direct logical connection between S6 and S7. In addition, S7 doesn’t refer to the US government.
8	D As a result, United States federal regulations mandate that all ambient classroom sounds above 90 decibels must be dampened; federal grants are made available for school districts to improve acoustics and soundproofing when these levels are exceeded.	Correct. “These facts” now refers to everything in the paragraph up to this point. Moreover, in this location, the new sentence provides an appropriate transition to S8, which describes the response of the US government to the issue.

	In recent years, these facts have caught the attention of the United States government. Where would the sentence best fit?	Insert Text. Wherever this new sentence is inserted, the prior sentence should refer to facts that are acted upon by the US government in the following sentence. Otherwise, the position of the new sentence will not make sense.
✗	A Choice A
✗	B Choice B
✗	C Choice C
✓	D Choice D	Correct.

	Whole Passage	Comments
P1	It should come as no surprise to any teacher or parent that noise in a classroom environment is distracting and may impact a student’s ability to learn…	Classroom noise is distracting, of course. But what kinds? Other questions. Research can shed light.
P2	Perhaps the most consistent finding of the new research is the degree to which even low levels of noise can have a substantial impact on student performance…	Even low noise levels can impact student performance. Decibel scale. 90 decibels: hearing loss can begin. Children are even more sensitive. So US regulations: classrooms must dampen sounds above 90 decibels. Grants to help.
P3	New research, however, indicates that learning issues begin at a much lower noise level…	But much lower noise levels can hurt learning. Even really quiet noises can increase cortisol, a “stress hormone.” Cortisol can interfere with learning. Studies have linked noise to learning problems.
P4	Another interesting finding is that different types and levels of noise can have varying effects on different groups of children…	Different noises can have different effects on different children. Study on white noise. Students who could focus well: most affected. Students with attention difficulties: actually improved at low levels of noise. Possible reason: these students had to exert more effort to overcome noise. That improved focus.
P5	Finally, increased noise can place undue burden on teachers…	Noise burdens teachers, too. They have to shout over background noise. Resulting problems.

	That classroom noise is undesirable may seem to be uncontroversial, but recent research has illuminated aspects of the issue that may be surprising.	Summary. Correct answers must be clearly expressed in the passage. They must also be among the major points of the passage. They should tie as directly as possible to the summary given.
✓	a United States law prevents background noise in classrooms from exceeding 90 decibels, but learning problems can begin at lower sound levels.	Correct. P2 discuss these facts in detail.
✗	b Only a small number of students are affected by low or moderate levels of background noise.	Even low or moderate levels of noise have been shown to affect student performance in general.
✗	c For every doubling of distance from a sound source, the perceived loudness drops by about 6 decibels.	This detail is mentioned in P5, but it is minor in the context of this passage as a whole.
✓	d Even low levels of noise in a classroom can lead to difficulties in such areas as reading, thinking, and coordinated movement.	Correct. This description from the end of P3 S7 neatly distills many of the difficulties encountered by students because of classroom noise.
✗	e Ninety decibels, the level at which hearing loss can begin, is roughly equal to the loudness of a lawn mower at a distance of 25 feet.	P2 mentions this fact, but it is a minor detail, meant as a concrete way to understand a particular noise level.
✓	f To overcome classroom noise, teachers must speak much more loudly, potentially resulting in serious health consequences.	Correct. Corresponds to P5.