Reading Passage 2

The Science of Sleep

(A) Sleep is a biological necessity, yet the precise function of sleep remains one of the most elusive questions in neuroscience. For centuries, philosophers and scientists have speculated on why humans and animals need sleep. While some theories highlight its role in memory consolidation, others focus on its function in physical restoration and metabolic regulation.

(B) The average adult needs about seven to nine hours of sleep per night, although this can vary widely depending on genetic and environmental factors. Sleep is not a passive state; rather, it is composed of complex stages. The most well-known division is between REM (Rapid Eye Movement) and non-REM sleep. Non-REM sleep includes deep sleep, during which the body undergoes tissue repair and growth. REM sleep, on the other hand, is associated with intense brain activity, vivid dreaming, and memory processing.

(C) Disruptions in sleep can have profound consequences. Chronic sleep deprivation is linked to a range of physical and mental health problems, including obesity, heart disease, depression, and weakened immune function. Studies show that even a single night of poor sleep can impair cognitive performance and decision-making. For shift workers and individuals with sleep disorders, the health implications can be severe.

(D) In recent years, researchers have explored the connection between sleep and learning. Experiments have revealed that people who sleep after acquiring new knowledge tend to retain the information better. During sleep, the brain seems to replay recent experiences, solidifying them into long-term memory. This has implications for education, leading to recommendations for adequate sleep among students.

(E) However, modern lifestyles often interfere with natural sleep patterns. Exposure to artificial light, especially from screens, suppresses melatonin production—the hormone that regulates sleep. Urban noise, stress, and irregular schedules further exacerbate the problem. As a result, sleep disorders such as insomnia and sleep apnea are on the rise.

(F) To counter this, sleep hygiene practices are recommended: maintaining a consistent sleep schedule, reducing screen time before bed, avoiding caffeine in the evening, and creating a restful sleeping environment. Although these measures may not resolve all sleep problems, they form the foundation for healthy sleep habits.

Reading Passage 3

The Role of Failure in Scientific Progress

In the public imagination, scientific discovery is often seen as a steady accumulation of facts, a linear journey from ignorance to knowledge. Yet, historians of science have long pointed out that real progress in science is often anything but smooth. It is riddled with failed experiments, abandoned theories, and serendipitous accidents. Thomas Kuhn, in his influential book The Structure of Scientific Revolutions, argued that science advances not just by the steady accumulation of data, but through paradigm shifts—radical changes in the conceptual frameworks that define a scientific field.

One of the most notable examples is the shift from Newtonian mechanics to Einstein's theory of relativity. For centuries, Newton’s laws were considered the ultimate description of the physical world. But as anomalies accumulated—such as the unexplained orbit of Mercury—scientists were forced to question long-standing assumptions. Einstein’s new model not only resolved these inconsistencies but also redefined concepts of space and time.

Failure in science is not only inevitable but essential. Without failed experiments, scientists would not learn the limits of existing theories. The scientific method itself is designed to test hypotheses in a way that may lead to their rejection. Karl Popper famously emphasized falsifiability as the hallmark of a scientific theory: a claim must be testable and potentially disprovable.

Still, in modern academic culture, failure is often stigmatized. High-impact journals tend to publish only successful outcomes, creating a publication bias. Young researchers, in particular, may be discouraged from pursuing risky or unconventional ideas that might fail. This aversion to failure could ultimately hinder innovation, as some of the most transformative discoveries emerged from unexpected results.

There is a growing movement to address this issue. Open science platforms now encourage the publication of negative results, and research institutions are reevaluating metrics that reward only high citation counts. Embracing failure, some argue, may not only improve transparency but also accelerate the pace of discovery.