General Science MCQs – Page 88 (Q871-880)

Anders Celsius, a Swedish astronomer, developed the now widely used temperature scale in which water reliably freezes at 0 degrees and boils at 100 degrees under standard atmospheric pressure, first proposed in 1742, though notably his own original scale was actually initially reversed from the modern version, with 0 degrees originally representing boiling and 100 degrees originally representing freezing. The now-standard Celsius scale was subsequently adopted, and later formally reversed to its familiar modern orientation, and it remains today the standard temperature scale used throughout most of the world, including Pakistan, for both everyday practical purposes and scientific measurement.

Daniel Gabriel Fahrenheit, a German physicist, developed an early, highly precise mercury thermometer and the corresponding temperature scale that bears his name, once commonly used throughout the United States and previously across much of the wider world, in which water freezes at 32 degrees and boils at 212 degrees under standard atmospheric pressure. Fahrenheit's specific scale was originally based on several carefully chosen reference points, including notably the lowest achievable temperature of a specific salt and ice mixture he could reliably produce at that particular historical time, and though largely superseded by the more scientifically convenient Celsius scale in most countries worldwide, it remains in common everyday use within the United States.

Joseph Priestley, an English chemist and clergyman, is generally credited among the earliest scientists to successfully isolate and correctly identify oxygen gas in 1774, though French chemist Antoine Lavoisier is more widely credited overall with correctly understanding and properly naming its true fundamental chemical nature and its genuinely essential role in combustion. Priestley's own extensive scientific work also included the significant discovery of several other important gases, and although he himself continued to actually believe in the ultimately incorrect phlogiston theory of combustion throughout his life, his careful, meticulous experimental work still provided essential foundational data for the subsequent Chemical Revolution.

Alfred Nobel, a Swedish chemist and engineer, invented dynamite in 1867, a significantly safer, more stable, and more practical explosive than the highly volatile and dangerously unstable nitroglycerin previously used, and he later established the prestigious international Nobel Prizes using the substantial fortune he had personally accumulated from his invention, reportedly at least partly motivated by his own genuine desire to leave behind a more positive, constructive, and lasting overall legacy. The Nobel Prizes, first formally awarded in 1901, now annually recognize outstanding, groundbreaking achievements across physics, chemistry, medicine, literature, economics, and peace, remaining among the most prestigious and internationally recognized awards in the entire world today.

Zacharias Janssen, a Dutch spectacle-maker, is generally credited, along with his father Hans Janssen, with building some of the earliest practical compound microscopes around the year 1590, combining two separate carefully aligned lenses together to achieve significantly greater overall magnification than any single lens could reliably achieve alone. This early foundational invention, though initially quite limited and relatively primitive by later standards, eventually paved the essential way for significant subsequent microscopy advances made by later scientists including Robert Hooke and Anton van Leeuwenhoek, both of whom used further improved microscopes to make their own genuinely groundbreaking biological discoveries.

Beyond developing pasteurization, Louis Pasteur is also well known for developing an effective vaccine against rabies in 1885, successfully treating a young boy who had been severely bitten by a rabid dog, marking the very first successful human application of a rabies vaccine and preventing what would otherwise have been an almost certainly fatal disease outcome. Pasteur also developed an earlier effective vaccine against anthrax in domestic livestock, and his combined extensive body of work on vaccination, pasteurization, and germ theory collectively established him as one of the single most influential and important figures in the entire history of medicine and microbiology.

Paul Ehrlich, a German physician and Nobel laureate, pioneered the field of chemotherapy in the early twentieth century by developing Salvarsan, an early effective chemical treatment for syphilis, representing one of the very first successful examples of a targeted chemical compound specifically designed to selectively kill disease-causing pathogens while causing comparatively minimal harm to the surrounding human host tissue. Ehrlich's genuinely pioneering concept of a magic bullet, a chemical compound capable of precisely targeting specific disease-causing agents, fundamentally helped establish essential important foundational principles that continue to substantially guide modern pharmaceutical drug development and targeted medical treatment today.

Christiaan Huygens, a Dutch scientist, proposed an influential early wave theory explaining the behavior and propagation of light in the seventeenth century, suggesting that light propagates outward as a continuous wave rather than as a stream of discrete particles, directly contrasting with Isaac Newton's competing corpuscular theory of light proposed around roughly the same general historical time period. Huygens's wave theory was later substantially further developed and definitively strengthened by subsequent scientists including Thomas Young and James Clerk Maxwell, and it eventually became the scientifically dominant view, though modern quantum physics has since shown that light actually genuinely exhibits both wave-like and particle-like properties simultaneously.

Isaac Newton's corpuscular theory of light, proposed during the seventeenth century, proposed that light was fundamentally composed of tiny individual particles, which he specifically termed corpuscles, traveling outward in straight lines at extremely high speed, an alternative theoretical view that directly competed against Christiaan Huygens's alternative wave theory of light proposed around the same general historical period. Although Newton's specific corpuscular theory was later largely superseded by the wave theory following subsequent experimental work, modern quantum physics has since shown that light genuinely exhibits both wave-like and particle-like properties simultaneously, meaning Newton's original core particle-based intuition ultimately contained a genuine, significant grain of underlying scientific truth after all.

According to historical accounts, Zhang Heng, an ancient Chinese scientist, astronomer, and inventor working during the Han dynasty, is credited with inventing an early device to detect earthquakes in the year 132 CE, an ingenious mechanical instrument capable of indicating both the occurrence and the approximate general direction of a distant earthquake using a clever arrangement of internal pendulums and dragon-shaped mechanisms that would release a ball to indicate the specific direction of the detected seismic disturbance. This remarkably early invention, developed many centuries before comparable Western seismological instruments, reflects the genuinely advanced and sophisticated state of scientific and technological innovation achieved within ancient Chinese civilization.