Science

First, we have to straighten out some terminology: • Penicillin (not penicillium) is the name of the drug. • Penicillium (not penicillin) is the genus of the mold that produces the drug. • Listeriosis and brucellosis are diseases caused by bacteria, not the names of the bacteria themselves. The drug. The oft-told story of the … Read more

The percentage sign on the label of a Brie cheese is the percentage of fat in the cheese, but expressed on what a chemist would call a dry weight basis, which is the percentage of fat in what would remain after all the moisture were removed. The famous and ancient (eighth-century) French soft cheese called Brie, … Read more

Cream cheese and cottage cheese are not purely American, but primarily so. What cream cheese and cottage cheese have in common, along with French Neufchatel and a few others, is that they are not aged or ripened. The milk or milk-and-cream mixture is curdled by an acid (usually lactic acid), and the curds are ready … Read more

Ice cream shrinks when it’s melted because it is half air. Federal regulations specify that the amount of “overrun” in ice cream must be less than t00 percent. Overrun is the increase in volume between the product’s ingredients and the final, air-whipped product. A doubling of volume, known as t00 percent overrun, means that the … Read more

Most people seem to think so that eating ice cream in hot weather cools you off. At the local Dairy Queen there is always a long line of people seeking cool after-dinner desserts in the summer, but starting the day after Labor Day, the place is virtually “desserted.” The answer to the question is in … Read more

As (chocolate) Dairy Queen aficionado myself, we conducted an investigation. I bought a quart container of soft-serve ice cream and measured its temperature by plunging an instant-read thermometer into the middle and waiting for a couple of dozen “instants” until it reached its final reading. On the two occasions it measured 14 and 16°F (-10 … Read more

In principle, and in many countries of the world, yogurt is very simple. It is made by adding certain strains of beneficial living bacteria to the milk from a cow, goat, or sheep. The bacteria feed on the lactose (milk sugar) in the milk, metabolizing it into lactic acid and other interestingly flavored chemicals, some … Read more

Cream is made from milk by boosting the percentage of milk fat (also called butterfat, because it is made into butter) beyond the percentage the cow put into it. That is, some of the watery, non-fatty part of the original milk (the “skim milk”) is removed to increase its “richness”: its smooth, unctuous mouth feel. … Read more

Remember when true skim milk was blue-white, and the edge around the glass was translucent? Why can’t we have good old skim milk back again? When a billboard asks, “Got milk?,” we may be tempted to reply, “Can you be more specific, please? Are you asking about raw milk, pasteurized milk, homogenized milk, aseptically packaged … Read more

I have heard about all sorts of treatments for removing red wine stains from tablecloths and clothing. The things I hear about most often are club soda and salt, but I’ve tried both without success. There must be a way that really works. Many people have asked my expert advice on this profound scientific question. … Read more

Having spent decades on a university campus (no, it didn’t take me that long to graduate; I was on the faculty), I have heard more than a little about what the students call “hearty parties.” Translation: binge drinking. But the college crowd doesn’t have a monopoly on binging, whether deliberate or accidental. For us in … Read more

First, the colder the ice the better. Colder ice will cool the liquid faster, just as colder rocks would do. And melting is not necessary for cooling; cold rocks would do the job as well. If two substances are in contact, heat will flow automatically from the warmer one into the cooler one. In this … Read more

Any dyed-in-the-cotton Southerner knows there is “plenty” in mint juleps. When sipped at the speed of a Southern drawl on a hot summer’s eve beneath a fragrant, blooming magnolia, few beverages are more refreshing than a mint julep, or more insidiously intoxicating, because its seductive sweetness masks the fact that it is virtually straight bourbon. … Read more

What sets Kentucky bourbon and Tennessee sour mash whiskey apart is largely local pride, but virtually identical whiskey can be made anywhere. They just can’t use those state names if they were made, for example, in North Dakota. First, what is it that makes bourbon bourbon? Bourbon is officially defined by the federal Alcohol and Tobacco … Read more

When planted in the bottle, champagne corks were just as cylindrical as the corks used in still wine bottles, only bigger. A normal-sized wine cork is 24 mm (about 0.94 in.) in diameter; it is compressed and inserted into an 18 mm (o.71 in.) bottle neck by a “corker” machine. Cork is quite compressible. Champagne … Read more

A silver fork would work just as well to prevent champagne from going flat. So would a railroad spike. Or a magic wand, for that matter, because the spoon does absolutely nothing. The spoon dodge is pure bunk. Or, in British terms, humbug and poppycock. Champagne simply doesn’t go flat as fast as beer and … Read more

There are some five thousand varieties of wine grapes that could be used in almost one hundred appellations d’origine in France alone, plus seventy-four appellations in California, not to mention Australia, Chile, and dozens of other wine-producing countries. Multiplied by perhaps ten years of vintages, that amounts to over 37 million possible bottles of decent … Read more

Sulfites, not to be confused with sulfates, are a family of chemical salts derived from sulfur dioxide (SO2). They are formed during the fermentation of wine from sulfur compounds naturally present in the grapes, so a certain small amount is indeed natural and unavoidable. In addition, sulfites (or sulfur dioxide gas from burning sulfur) have … Read more

Hops are the dried flowers of the hop plant, known to botanists as Humulus lupulus. It’s a tall, climbing vine of the hemp family, and its flowers impart that mellow bitterness to beers and ales, balancing the sweetness of the malt. They also contribute a grassy flavor note and a pleasant aroma, depending on when … Read more

Even though they are members of the same chemical family, there are vast and crucial differences among the alcohols, and it can be a matter of life and death to be aware of them. Alcohols are a large family of organic (carbon-containing) chemicals that are related in two ways: their molecules contain one or more … Read more

There is a difference between what a chemist calls a calorie and what a nutritionist calls a calorie. The chemist’s calorie is the amount of heat energy required to raise the temperature of one gram of water by one degree Celsius, whereas the nutritionist’s calorie, the calorie you see in diet books and on food … Read more

I doubt that the ancient Greek philosophers spent much time on this (especially since they didn’t have coffee), but it’s a challenging question, if not an earthshaking one. You could settle it with an accurate thermometer, but you’d have to measure out exactly the same amounts of coffee and cream into exactly the same type … Read more

Most connoisseurs agree that in order to extract the proper amount of flavor from black or oolong tea leaves, the water must be as hot as possible. But no matter how much you heat it, water will never get hotter than boiling: 212°F (100°C), minus a degree or two, depending on the altitude and weather. … Read more

Caffeine is very soluble in water; as much as 150 grams of caffeine could dissolve in a cup of boiling-hot water. But there isn’t anywhere near that much caffeine in a tea bag. Typically, it’s less than a thousandth of that. What caffeine there is is extracted out of the tea bag almost completely in … Read more

Here’s what was going on in the tea when you add baking soda. You’ve heard people talk about a “litmus test,” to show whether a politician is on one side of an issue or the other? Well, litmus is a dye obtained from lichens; it is pink when in an acidic environment and blue when … Read more

Enzymes have been misunderstood almost as much as instruction manuals for VCRs. Everyone know that enzymes play essential roles in all living things, but what exactly are they? Are they alive, like bacteria? No. They’re chemicals, almost all of them proteins, that accelerate the complex chemical reactions essential to living things, both plant and animal. … Read more

All tea comes from the same, one-and-only tea plant, Camellia sinensis, whose leaves certainly were chlorophyll-green on the living plant. But based upon how the leaves are processed, there are three types of tea: green, which is consumed mostly in the Far East; black, the favorite of the British and other Westerners; and oolong (“black … Read more

Tea leaves contain tannins, a loose collection of chemicals that give tea much of its flavor and body, and especially that astringent, puckering effect in the mouth. They dissolve in water to form a clear solution, as long as the water isn’t too cold or slightly alkaline. Your cloudiness occurs when some of the tannins … Read more

Let’s follow the fate of the soda from the time that rascal put it in the freezer, probably with the misguided intention of keeping it nice and fizzy till the next attack of thirst. All liquids turn into solids, that is, they freeze, when they get cold enough. Pure water freezes at 32°F (0°C), but … Read more

There was a time, a little more than a hundred years ago, when people didn’t believe in germs. Nineteenth-century doctors knew a lot about disease, they could diagnose your illness correctly and tell you quite accurately how much time would pass before you would either get better or drop dead. But because knowledge of the … Read more

Isaiah Berlin developed the distinction in his 1958 inaugural address as Chichele Professor of Social and Political Theory at Oxford University. Negative liberty is the absence of constraints or interference with individual action, as in a person being free to vote, write a book, or study ballroom dancing. Positive liberty is the human capacity for … Read more

Researchers set traps to capture a population sampling in a given area. The captured animals are “marked” (or tagged) and then released. After a certain amount of time the traps are set again. The second time, both marked and unmarked animals will be captured. The proportion of marked to unmarked animals gives an estimate of … Read more

Despite its perceived resemblance to the outer female reproductive organs, apparently noticed by very lonely gardeners, the orchid was actually named after male genitalia. The name orchid comes from the Greek orkhis, meaning “testicle.” It was adopted because of the orchid’s testicle shaped root. This resemblance may have led to the belief that orchids were … Read more

There are thousands of corn hybrids, but almost all fall into six general groups. The most common variety grown in the United States is dent corn, used for chemicals and animal feed. Sweet corn is the kind most people consume, on or off the cob; its sugar doesn’t convert to starch, so it is sweeter … Read more

The order of the colors in a rainbow from top to bottom are red, orange, yellow, green, blue, violet. However, if you see a double rainbow, with a larger but fainter secondary rainbow outside the main rainbow, the colors will be reversed in the second rainbow. A supernumerary rainbow, also also known as a stacker … Read more

The word calculus means “pebble” in Latin. Pythagoreans used pebbles, lined up to form various shapes, to represent numbers. The earliest ideas that led to integral calculus can be found in the Egyptian Moscow papyrus, and described calculations of volumes and areas, one goal of integral calculus. Historically, calculus was known as “infinitesimal calculus”. Archimedes … Read more

Microwaves sure won’t do you any good. Even small doses of microwave energy might do long-term damage, and larger doses can cause a dangerous buildup of heat, especially in body parts like eyes, which don’t cool quickly. Having said that, though, it’s also true that people stationed at microwave towers used to stand in front … Read more

English author and philosopher Francis Bacon was the forerunner of the great frozen-food scientists of the early 20th century, such as naturalist and author Clarence Birdseye. Bacon did many experiments with meat and discovered the undeniable connection between meat preservation and subfreezing temperatures. Tragically, his experiments killed him. While on a joumey in March 1626, … Read more

The Richter scale is a logarithmic scale that gauges the magnitude of an earthquake’s force. Invented by Charles Richter in 1935, it is measured on a seismograph machine, interpreting the data the machine picks up from the Earth’s vibrations. Each number is 10 times more powerful than the previous number. For example, a quake that … Read more

In 1960, Louis Leakey found the skull, leg, foot, and hand bones of another hominid in Tanzania, East Africa. It was dated at around 2 million years old, just slightly older than Zinj. The bones showed that this ancestor walked on two feet and had a large brain, but there were differences. The teeth were … Read more

Alfred Wegener conducted four expeditions to Greenland to study its atmosphere and ice cap. On the second expedition, he completed the longest crossing of an ice cap ever made on foot (750 miles). The fourth expedition, in 1930, was to establish three weather stations on the island. One station on the west coast was set … Read more

Once scientists realized that fossils were a key to uncovering Earth’s past, the search was on for more, older fossils. Three main new sciences grew out of these studies, paleontology, archaeology, and anthropology. Paleontology is the study of fossils, including those of humans, animals, and plants. Archaeology is the study of past human culture and … Read more

There are four main developments in human evolution that led to today’s Homo sapiens: walking on two legs instead of four; a larger, more complex brain; the making of tools; and language. The development of all but language could be revealed by studying fossils of hominids, members of the family that include humans and apes. … Read more

In the nineteenth century, scientists discovered that Earth was much older than previously thought. Humans and other animals had been on Earth much longer also. Some animals had lived on Earth before humans and become extinct. This raised many questions. How old was Earth? When did life start? When did humans appear? In 1925, Australian … Read more

Just as Alfred Wegener was getting his degree in astronomy, the new science of meteorology was getting a boost from some new scientific advances. The telegraph, the laying of the Atlantic cable, and wireless communications were making storm tracking and weather forecasting much more accurate. Wegener became a meteorologist. He used kites and balloons to … Read more

Some of the instruments used by the scientists on the Challenger expedition were remarkably simple. Measuring the depth of water is called sounding. Their sounding device was simply a very long rope with a heavy weight (over 100 pounds) attached to the end. The machine lowering the rope had a counting wheel to record the … Read more

The H.M.S. Challenger returned to England on May 24, 1876. All the oceanographic findings of the Challenger expedition would take 20 years to compile into 50 volumes and almost 30,000 pages. Charles Wyville Thomson was able to complete a two-volume account of the main findings before his death in 1882. The most remarkable discovery of … Read more

Alfred Wegener was so sure of his theory on the origin of the continents that he gave the original continent a name, Pangaea, which means “all of Earth” in Latin. In his research, he found much more support for the theory, in addition to the fossil findings in Greenland. Wegener created a map of Pangaea … Read more

In 1596, the Flemish mapmaker Abraham Ortelius proposed a strange theory. He suggested that all the continents of Earth were once joined together and had drifted apart over the course of time due to earthquakes and floods. He offered no evidence other than that the coastlines of Africa and South America seemed to fit together … Read more

Without the ultimate proof of the force behind continental drift, Alfred Wegener’s theory was rejected by most as a fairy tale. The first hint of proof came right after Wegener’s death, with the confirmation of the submerged mountain range called the Mid-Atlantic Ridge under the Atlantic Ocean and a central valley along its crest. Wegener … Read more

People had some strange ideas about fossils when they were first discovered. Some thought that dinosaur bones were the remains of a race of human giants. Even when it became clear that the fossils were the remains of strange, previously unknown animals like mastodons, some thought these animals must still exist in unexplored areas of … Read more

Some cosmologists have taken Stephen Hawking’s work and proposed that the same black hole process that formed our universe may have occurred more than once to form other universes. They say that structures called wormholes might connect our universe to others. These same wormholes might connect different parts of our universe that are millions of … Read more

Like Albert Einstein, Stephen Hawking hopes for “a complete, consistent, and unified theory of the physical interactions which would describe all possible observations”, a theory for everything. Sometimes there are contradictions in science’s greatest breakthroughs. For example, Newton’s theories explained gravity and motion, and Maxwell’s theories explained radiation, but the two could not agree on … Read more

One night, Cuvier’s students decided to play a trick on their professor. They dressed up in devil’s costumes and woke up Cuvier in the middle of the night, chanting, “Cuvier, Cuvier, we have come to eat you!” Cuvier opened his eyes and took a good look at his pretend attackers. He said, “All animals with … Read more

Before Charles Darwin came up with his theory of evolution in 1859, biologists debated how to explain the similarity and diversity among animals, and Georges Cuvier was right in the middle of the debate. Cuvier was brilliant at anatomy, but he made the mistake of dismissing evolution. Both of France’s other leading biologists at the … Read more

A few scientists before Georges Cuvier believed that fossils were the remains of species that no longer existed, but religion was still a powerful force in science in Cuvier’s time. Many scientists could not believe that God would create living things only to wipe them out later. Cuvier decided to settle the issue. For his … Read more

Charles Darwin took a copy of Charles Lyell’s Principles of Geology with him on his around the world research voyage aboard the HMS Beagle. Darwin was just beginning to formulate his ideas on evolution, and Lyell’s findings would have a deep influence on him. There’s little doubt that Lyell’s basic belief that Earth had undergone … Read more

In 1650, Archbishop James Ussher of Ireland used the history of Earth presented in the Bible to calculate that the world had been created in 4004 B.C. If this were true, how could fossil formations be explained? More and more fossils of plants and animals were being uncovered in thick layers of rock. Sometimes the … Read more

Charles Lyell was born into wealth in Kinnordy, Scotland, in 1797. His father was a skilled botanist, and Lyell, growing up on the family’s huge estate, acquired a love for the natural world. His family decided, however, that he would study law at Oxford because science was not considered a “gentleman’s” profession. Lyell completed his … Read more

In 1795, the Scottish geologist James Hutton wrote a book called Theory of the Earth. Hutton had a new theory about how Earth formed. He said Earth was probably millions of years old. Hutton rejected Cuvier’s catastrophism and said changes had occurred slowly over these millions of years from simple forces, like erosion and sedimentation, … Read more

The British government provided Charles Wyville Thomson with the HMS Challenger warship for the Challenger expedition. It was a 200-foot sailing ship, but it was equipped with a 1,200-horsepower engine to power dredging experiments. All but two of the ship’s 18 guns were removed and replaced with scientific laboratories and storage space. The ship had … Read more

Who Was Sir Charles Wyville Thomson and How Did the Challenger Expedition Help Advance Oceanography? For thousands of years, humans navigated the open seas with very little idea of what lay beneath them. By the late nineteenth century, humans knew more about the universe and the atom than Earth’s oceans. Early studies of the oceans … Read more

Charles Lyell’s most unusual idea in his book “Principles of Geology” was that the pattern of life on Earth might occur in cycles. Some fossil discoveries were already revealing evidence that huge reptiles, later named dinosaurs, roamed Earth long before humans had. According to Lyell’s idea of cycles of life, these reptiles might return one … Read more

The scientists on board the Challenger were experts in biology, chemistry, geology, and physics, and Charles Wyville Thomson’s plan for the voyage was very ambitious. They would record data and collect samples at 362 observation stations around the world. Here’s a list of the observations and experiments that were performed at most stations: The depth … Read more

The skies are full of variable stars. These are stars that go through a cycle of fading and brightening, so they look like they’re winking. Cepheid variables have very quick cycles, some as short as 12 hours. In 1912, American astronomer Henrietta Leavitt discovered a connection between a Cepheid’s cycle and its brightness: the slower … Read more

At the start of the twentieth century, the perception of the universe was still limited to Earth’s own Milky Way system, which scientists thought measured no more than 20,000 light-years across. William Herschel had theorized 100 years earlier that there were other separate systems far outside our own, but most astronomers doubted this. There were … Read more

After Edwin Hubble’s galactic discoveries, many scientists felt that for the first time in history we understood the key elements of the structure of the universe. In 1922, the Russian mathematician Alexander Friedmann used Einstein’s theory of relativity and Hubble’s theory of an expanding universe to propose the big bang theory to explain the origin … Read more

Edwin Hubble’s study of galaxies led him to a classification system based on shape and composition into regular and irregular forms. He found that 97 percent of the regular galaxies had elliptical or spiral shapes. He divided spiral galaxies into two types: normal and barred. The arms of a normal spiral stretch out from a … Read more

If Hubble’s law proves correct for the entire universe, it will help us estimate the age and size of the universe. In fact, the radius of the measurable universe is called the Hubble radius. There is one problem, however. The galaxies in the outer reaches of the universe move faster and faster. Astronomers have detected … Read more

In the nineteenth century, astronomers discovered that studying the light emitted from a star, a study known as spectrum analysis, revealed what elements stars are made of. Changes in a star’s spectrum indicate the movement of the star, and analysis could determine the star’s speed and direction. It was revealed that stars only appear fixed … Read more

Vera Rubin was not the first astronomer to suggest that there is invisible matter in the universe. In the 1920s, the Dutch astronomer Jan Hendrik Oort found that the velocity of stars in our own Milky Way did not conform to Newton’s laws of gravity. However, he thought that the problem was in his observations … Read more

The big bang theory states that the present universe was born in an incalculable explosion of matter and gas. Albert Einstein had proposed the idea early in the twentieth century, and Hubble’s discoveries about galaxies seemed to confirm it. Vera Rubin’s next discovery would raise questions about the theory. The big bang theory predicted that … Read more

Rubin’s first discovery was amazing for several reasons. When she made it, she was still just a 22-year-old student from the virtually unknown graduate department at Cornell. When she presented her findings to the American Astronomical Society in 1950, she was practically booed off the stage. Several years after her presentation, however, her findings would … Read more

Vera Cooper Rubin was born in Philadelphia, Pennsylvania, in 1928 and knew from a very early age that she wanted to study the stars. She built her own telescope at 14 and attended Vassar College because her heroine, astronomer Maria Mitchell, had founded the astronomy department there. There were so few graduate schools that accepted … Read more

Hawking believes that the conditions in a black hole are the key to our entire universe and the big bang theory. In a black hole, matter collapses into an infinitely dense, infinitely small point. Hawking says that if you reverse the process, you have an infinitely dense, infinitely small point, surrounded by nothingness, exploding outward … Read more

In the 1960s, English mathematician Roger Penrose came up with the idea of singularity. A singularity occurs when an object becomes smaller and smaller from being crushed but does not lose any matter. Even the atoms and subatomic particles are crushed. The process continues indefinitely until the object is infinitely small and infinitely dense. Astronomers … Read more

By the 1960s there were two theories that tried to explain the origin of the universe. The big bang theory said that there was an immense explosion 12 to 20 billion years ago and that the universe was still expanding outward from that explosion. Astronomers who believed in the big bang said the movement of … Read more

In the 1970s, Vera Cooper Rubin started what seemed like an innocent experiment with another American astronomer, Kent Ford. Rubin wanted to determine why spiral galaxies differ in structure. She decided to compare the movements of stars near the center of a galaxy with those in the outer reaches of the galaxy. Rubin chose the … Read more

By 1781, Herschel had become an expert telescope maker and had built the most powerful telescope in the world. One night while he was working on his catalog of the stars, he saw something near the constellation Gemini that he hadn’t seen before. He could tell it was not a star from its movement, so … Read more

The key to William Herschel’s discoveries was his telescopes. His desire to see farther and farther into space meant that he had to become an expert in optics as well as astronomy. By 1779, he had built the best collection of telescopes in the world. His best was a 7-foot instrument with a 6-inch mirror … Read more

After William Herschel’s discovery of Uranus in 1781, astronomers studied the new planet carefully, but something was wrong with its orbit. It went wildly off track, and some scientists even started to question Newton’s laws of gravity. The mystery remained unsolved until 1846, when another planet was discovered in orbit beyond Uranus. English astronomer John … Read more

It’s hard to top the discovery of the first planet since ancient times, but William Herschel’s next observation was so amazing that few astronomers believed it until it was proven 150 years later. As telescopes became more sophisticated, astronomers began to see misty objects much farther away that were definitely not stars. They came to … Read more

After William Herschel proposed his theory of “island universes”, or galaxies lying far outside our own Milky Way, astronomers became curious about measuring the distance to the stars. In 1838, the German astronomer Friedrich Bessel used improved telescopes and a technique called parallax to prove that the universe was much more vast than even Herschel … Read more

In 1609, Jacques Badovere wrote a letter to his former teacher telling him of an amazing new instrument from Holland called a “Dutch cylinder.” With one convex lens placed in front of one concave lens inside the cylinder, the instrument made distant objects appear much closer. Ships miles away at sea could be seen approaching … Read more

As science moved toward experimentation to prove its theories, tools of measurement became vital. The measurement of time was probably the most important of all, but in Galileo’s time, scientists had not yet invented a dependable timepiece. Ancient humans could measure years, months, and days with the movements of Earth, the Moon, and the Sun. … Read more

It had been 70 years since Copernicus proposed that the Sun, not Earth, was the center of the universe. The academic world, however, was still teaching the Ptolemaic system, with an unmoving Earth at the center. Most scientists simply did not believe Copernicus’s theory; others who did and tried to teach it were burned at … Read more

By the late eighteenth century, the development of the telescope had made it possible for many amateur astronomers to search the skies. Most were content to view what was already known, while some dreamed of great discoveries. One 41-year-old musician in Bath, England, wanted to systematically catalog the whole sky. This amateur wound up making … Read more

If Galileo Galilei had never looked through a telescope, he still would have been considered a great scientist. His findings on the laws of motion set the stage for the work of Sir Isaac Newton one generation later. Galileo not only proved that weight does not affect how quickly objects fall, he also proved that … Read more

When Enrico Fermi was conducting his experiments with neutrons and the elements, he was looking for a better, artificial way to produce radioactivity, not nuclear fission. When he got to uranium, he was concerned that its very high level of radioactivity might harm his instruments. Fermi placed a sheet of aluminum foil between the uranium … Read more