Karen Hill

Quite obviously, sticking can’t occur unless there are two distinct materials; there must be both a sticker and a stickee. The properties of both must be considered. But can there be such a thing as an intrinsic non-sticker, regardless of what the stickee may be? This non-sticky question was settled in 1938, when a Du … Read more

It’s very good for those who manufacture the salt mills and peddle them to yuppies who must own the ultimate pseudo-gourmet accessory. For the rest of us? It’s a scam. Pepper should be ground fresh, but grinding salt accomplishes nothing, but exercise. Freshly ground black or white pepper (which are identical plant berries that have … Read more

Is sea salt healthier than ordinary salt? Baloney. The sea salt that’s sold in supermarkets and health food stores is no richer in minerals, no less refined, and no different in flavor from ordinary table salt. But you’ll pay anywhere from four to twenty times as much for it. And it may not even come … Read more

It is, of course, entirely unnecessary to point out that salt is inherently nondenominational. While kosher salt comes from the sea and is certified at the factory as meeting the strict criteria of Jewish dietary laws, the rabbi’s blessing has no more effect on flavor than does the priest’s consecration of a communion wafer. Kosher … Read more

What is friction? When you rub the surfaces of two objects together, they’ll resist slipping and sliding to some extent, and some of the muscle energy that you’re applying to overcome that resistance shows up as heat. And what is heat? It’s just molecular motion. What microwaves do is make certain molecules move, and once … Read more

The melting point and the freezing point of a substance are the same thing. The solidification process is what we also call freezing. When we say that water freezes at 32 degrees Fahrenheit (0 degrees Celsius), we could just as well say that that’s the melting point of ice. The reason they are the same … Read more

Who says you can’t melt salt? Any solid will melt if the temperature is high enough. Lava is molten rock, isn’t it? If you want to melt salt, all you have to do is turn your oven up to 1474 degrees Fahrenheit (801 degrees Celsius), which will make your kitchen glow a pretty red color. … Read more

The short answer is that baking soda is a single, pure chemical compound, while baking powder is a mixture of that same chemical with one or two others. (If you must know, baking soda is sodium bicarbonate or bicarbonate of soda, while baking powder is sodium bicarbonate plus an acid or two: tartaric acid or … Read more

Butter is clarified to get rid of everything but the pure saturated fat. Some people think of butter as a block of fat surrounded by guilt. But guilt or no guilt, it isn’t all fat. It’s a three-part, solidified emulsion, a stable mixture of oily and watery components, with some solids mixed in. When you … Read more

Fish flesh is inherently different from the flesh of most walking, slithering, and flying creatures for several reasons. First of all, cruising through the water doesn’t exactly qualify as body-building exercise, at least when compared with galloping across the plain or flitting through the air. So fish muscles are not as developed as those of … Read more

The short answer is that cooking makes proteins harder and carbohydrates softer. We’ll leave meats out of this, because the toughness or tenderness of a cut of meat depends in a very complex way on the muscle structure of the animal, the portion of the animal it came from, and on precisely how it’s being … Read more

Candy recipes tell you to boil sugar syrup until it reaches various temperatures on a candy thermometer: the soft ball stage at about 237 degrees Fahrenheit (114 degrees Celsius), the hard crack stage at 305 degrees Fahrenheit (152 degrees Celsius), and so on. Different cookbooks will give you slightly different temperatures for the various stages.) … Read more

The difference between simmering and boiling is more basic than just the vigor of the bubbling. A simmer aims to produce a slightly lower temperature than true boiling, because even a few degrees difference in cooking temperature can make a big difference in how things cook. In moist cooking, cooking with lots of water present, … Read more

It’s strange, but true. The boiling water will indeed begin to boil at a higher temperature as soon as the salt dissolves. For every ounce of salt that you add to a quart of water (or for every 29 grams of salt per liter of water), the boiling temperature will increase by about 0.9 degree … Read more

Not a lot of steam is lost until the water starts to boil, but water vapor, yes. Long before you ever see any steam, which is made up of tiny droplets of liquid water, there is a lot of invisible, hot vapor being produced, unattached water molecules, flying around as a gas. A vapor and … Read more

Dive into the science of boiling water and the intriguing question: Can water get hotter than its boiling point? Uncover the mysteries behind this common yet complex phenomenon. Key Takeaways: Explore the science of water boiling and the factors influencing its temperature. Understand the concept of superheating and the conditions under which water can exceed … Read more

Bleach doesn’t know which clothes are white. What it does know about is color, because color is a lot more fundamental, chemically and physically speaking, than our mere human wash day preferences. Bleach attacks colored chemical compounds, most of which do indeed have something in common, and leaves behind a lack of color that we … Read more

Inside the battery, electrons are indeed passed from one atom to another like jumping fleas. But that’s not how electricity flows through a wire or through a complicated electric circuit. The electrons don’t just enter one end of a wire, hop from one atom to the next, and come out the other end. Let’s say … Read more

Batteries do not contain electricity as such; they contain the potential for electricity in the form of chemicals. These chemicals are isolated from one another inside the battery and are thus prevented from reacting until we hook up the battery to a device and turn on the switch. Then they react and produce electricity. Getting … Read more

If you look carefully, you’ll see a narrow constriction in the capillary tube through which the mercury travels up and down. On its way up, the mercury has plenty of force to overcome the resistance and push through the constriction; the pressure of an expanding liquid can be quite high. (When water freezes and expands, … Read more

Heat makes things expand. In a compression faucet (the most common kind), the water flows through a narrow gap between a neoprene rubber washer and a metal “seat.” In the hot-water faucet, the initial flow of hot water makes the washer expand, which closes down the gap between washer and seat, restricting the flow of … Read more

The normal temperature of an ice and water slush is 32 degrees Fahrenheit (0 degrees Celsius). But that’s not cold enough to freeze ice cream. It has to be at 27 degrees Fahrenheit (-3 degrees Celsius) or below. Salt is what does the job. Lots of other chemicals would do the trick, but salt is … Read more

Congratulations. Your friends think highly enough of you to put out their company tableware, which is made of sterling silver. Your home “silverware” is either stainless steel or (sorry about that) only silver-plated base metal. Sterling silver is almost pure silver: 92.5 percent, to be exact. And silver is the best conductor of heat among … Read more

There are several reasons why a glass of champagne has less bubbles than a glass of beer, none of them sociological. • The champagne is likely to have been poured into a flute, a tall, narrow glass that doesn’t have a lot of bottom surface for bubble formation. Moreover, such narrow glasses are not as … Read more

The trick, as you already suspected, is to chill the bottles well and avoid any agitation for at least several hours before opening. But knowing why always helps. Beer, soda, and champagne all get their fizziness from carbon dioxide gas, which has been dissolved in the liquid during, or in the case of true champagne, … Read more

When the sun is low in the sky at sunrise or sunset, you’re seeing it straight-on through a great distance of atmosphere. While traversing all that atmosphere, a lot of the blue light that started out in your direction gets scattered into many other directions, so the light that reaches you straight-on is depleted in … Read more

The sky is blue for the same reason that cigarette smoke is blue: the preferential scattering of blue light by tiny particles. Pure air is colorless, of course, meaning that all visible wavelengths (colors) of light pass through it without being absorbed. But it contains molecules and, often, suspended dust motes that are smaller than … Read more

Tar and nicotine are not blue, so forget that idea. What happened was that the size of the smoke particles had changed. The particles in cigarette smoke as it rises from a quietly burning cigarette are extremely tiny, smaller than the wavelengths of visible light. When a passing light wave encounters one of these tiny … Read more

The water in a water bed will indeed settle down to the same temperature as everything else in the room, including a conventional bed. But you would still feel colder on the water bed. It has to do with the fact that water conducts heat away from your body a lot more efficiently than other … Read more

The soda wasn’t frozen as long as it was still in the refrigerator because the refrigerator’s temperature was warmer than its freezing point. But when you pulled the tab you did two things: You released the pressure inside the can and you lost some of the gas. For different reasons, each of these effects helped … Read more

Unlike thermos, which has become a generic word, Styrofoam is still struggling to retain its identity as a trademark, but nobody seems to be paying attention; people call all polystyrene foam products “styrofoam” anyway. The material is a good insulator because the plastic foam contains billions of trapped gas bubbles. Gases hinder heat conduction because … Read more

To solve the problem, all you have to do is think of heat as a kind of liquid that flows only “downhill” from high temperatures to low temperatures. The thermos bottle acts like a dam that blocks the flow of heat. It won’t let heat flow “down” from your hot coffee inside to the lower-temperature … Read more

The common substance that contracts when heated is rubber. Stretched rubber. Most things expand when heated for a simple reason: The higher temperature makes the atoms or molecules move faster. They then need more elbow room, spreading farther apart on the average, and that makes the whole substance take up more space. But rubber can … Read more

A larger amount of gas can dissolve in a liquid when it is cold than when it is hot. Or as a chemist would say, the solubility of a gas in a liquid increases with decreasing temperature. But that’s how chemists talk. In practical terms, why does the carbon dioxide choose to leave the beer … Read more

Your objective is to keep as much carbon dioxide gas in the bottle as possible, because that’s what the fizzy bubbles are made of. Keeping the bottle tightly stoppered certainly has to be your first line of defense. But frankly, it won’t help very much. There are many kinds of stoppers on the market, including … Read more

It has to do with the fact that atoms and molecules that are heated in flames can absorb some of the heat energy and then promptly spit it back out as light energy. Every substance has its own typical wavelengths or colors of light that it emits after being stimulated by the heat. (Techspeak: every … Read more

It’s a matter of how much oxygen is available to the burning fuel. Lots of oxygen makes blue flames, while a limited amount of oxygen makes yellow ones. Let’s look at the yellow flame first. A candle is really a very complex flame-producing machine. First, some of the wax must melt, then the liquid wax … Read more

By capillary attraction, the wick leads melted wax up to where it can be vaporized and mix with oxygen in the air. A block of solid wax, or even a puddle of melted wax, won’t burn because the wax molecules can’t come in contact with enough oxygen molecules; only as vapors can they mix intimately, … Read more

Except for what drips all over your tablecloth, burning candle wax goes to the same place that gasoline and oil go when they burn: into the air. But in a chemically altered form. Candles are usually made of paraffin, which is a mixture of hydrocarbons, substances that we find in petroleum. As the name implies, … Read more

Rather than insulting everyone by pointing out why sheets will not be any softer if washed with soft water, I might gently state that hard and soft water are not called that because of their relative rigidities. Nor is it because you make hard boiled eggs with one and soft-boiled eggs with the other. The … Read more

There is an important thing that soap does: It makes water wetter. That is, it helps the water to penetrate into all the nooks and crannies of whatever it is we’re washing. Water molecules stick to each other quite strongly. As a result, a water molecule situated at the surface of a “piece” of water … Read more

It would appear that soap is a magic substance that recognizes and respects our skins and precious possessions while devouring everything else under the sun like a vulture leaving only bones behind. But no such magic substance exists. Instead, the answer has to do with the natures of oil and water. Simplistic as it may … Read more

The unholy mess involved in making soap belies its use as an incomparable cleaner of just about everything for at least the past two thousand years. It has always been easy to make out of cheap, readily available materials: fat and wood ashes. Lime was sometimes used also. You can make it the way the … Read more

It goes back to the fact that most humans are right-handed. Long before we had modern weapons such as guns and automobiles, people had to do battle using swords and horses. Now if you are right-handed, you wear your sword on the left, so that you can draw it out rapidly with your right hand. … Read more

The steam hammer was essentially a power hammer, as used today to shape forgings, but it was driven by a steam engine. It comprised a hammer-like piston within a cylinder positioned vertically in an iron frame. The central hammer piston was driven upwards by injecting high-pressure steam into the cylinder’s base, which was supplied by … Read more

The beam engine was used to draw out water from mines, as well as to pump water into canals. The engine consisted of a large wooden frame into which a pivoted overhead beam was used to apply force generated by a vertical piston and transfer that movement to a pump rod. The piston’s movement was … Read more

The invention of the steam engine and its practical implementation in the beam engines of the early-18th century was the catalyst. By mechanizing and automating the excavation of mines, not only could raw materials, such as coal and ores, be harvested in immense quantities, but the process could be executed at a speed simply infeasible … Read more

It’s a common misconception that steam is visible. The characteristic white mist that we see rising from a boiling kettle or the cooling tower of a power station is, in fact, haphazard clouds of water droplets forming through the condensation of steam in the cooler air. Indeed, if steam was simply a mist of water … Read more

The origins of Hurricane Sandy, one of the most costly superstorms ever, have been revealed by meteorologists. The storm caused over $20 billion (£12.5 billion) worth of damage and claimed more than 50 lives. Classified as a post-tropical cyclone, Sandy caused wide-scale destruction to buildings, left over 7.4 million properties without power and led to … Read more

A grandfather clock uses a pendulum to keep time, a swinging weight that oscillates back and forth at fixed intervals. However, if the pendulum swings once every second, a tiny error quickly spirals into a major timekeeping problem. The solution is to break the second down even further and to use a ‘pendulum’ that swings … Read more

Two decades ago, astronomers weren’t sure if any planets existed outside of our own solar system. Now they’ve identified more than 1,000 all over the galaxy. But in order to support liquid water and therefore life as we know it, a planet must be small enough, rocky, have an atmosphere that’s dense but not crushing, … Read more

Recumbent bicycles have been in production for decades, with a history stretching back to the 19th century along with its more familiar bicycle brethren. Recumbent bikes place the rider in a more horizontal position with more framing and a larger seat, with the alloy frame extended between the larger wheelbase to position the rider directly … Read more

On the surface there aren’t many things more solid than rock, but over thousands of years it can change dramatically. Nowhere is this more evident than the world’s coastlines where the rock is constantly under barrage. The hydraulic action of the waves slamming into the cliffs causes fractures, which over time grow into cracks, which … Read more

We’ve all taken things we never wear or use on holiday. This can be avoided with a little more foresight. Lay your gear out on the floor before putting a single item in your case and write a list of what you’ll need. Check what’s available at the accommodation to save taking big items like … Read more

As the global oil supply dwindles over the coming decades, plastics manufacturers will turn to natural gas, biomass and recycling as the feedstock of the future. Today, just about every plastic product, from Tupperware bowls to polyethylene carpet, is derived from petroleum, a non-renewable fossil fuel that will eventually dry up. The plastics industry has … Read more

Hero of Alexandria, a Greek engineer and mathematician who lived in the first century CE, introduced the first vending machine. For a small fee, you could purchase your very own holy water. A coin was placed into a slot where it fell onto a pan attached to a lever. The lever controlled a valve allowing … Read more

Radon is a radioactive, colorless and odorless gas that is found all around us in very small amounts and is responsible for most of our daily dose of radiation. Radon gas is one of the decay products of radium, which in turn is a decay product of uranium, the most common naturally occurring radioactive substance … Read more

The Globe Theater was an Elizabethan era playhouse part-owned by the great playwright William Shakespeare. Built from the remains of an existing theater in Shoreditch, London, made by English actor and theater owner Richard Burbage and his brother Cuthbert, the Globe was constructed over just a few months in 1599. The playhouse became the home … Read more

The pedoscope was a modified medical device consisting of a metal box, covered by wood and with a series of viewing portals. Marketed to shoe shops in the early-20th century, it claimed to enable sales assistants and customers to take a detailed look at the fit of a pair of shoes. The customer would place … Read more

The Peruvian coastal plain in South America is home to a wonder of archaeology. The ground is scarred by images, or geoglyphs, known as the Nazca lines, thought to have been constructed by the people of Nazca between 500 BCE and 500 CE. The ancient artworks, most easily viewed from the air, were created by … Read more

Imagine a beast taller than a giraffe and heavier than two elephants. Paraceratherium was the dinosaur of its day. It filled the same ecological niche as the huge sauropod dinosaurs, like Diplodocus, that lived 120 million years earlier, roaming through lightly forested plains and eating the leaves of trees, which it stripped off the branches … Read more

Tidal power plants use the rise and fall of tides to produce electricity. One way to harness tidal power is to build a barrage, a dam with gates that regulate water flow, across an estuary. When the gates are open, water flows through turbines, generating electricity. Water flows through at high tide, filling up the … Read more

Over 1 million cars are scrapped every year, but this is not the end of their life. Cars contain a wide variety of valuable metals that can be recycled and reused. Powerful car crushers compact the scrap steel, making it much easier to transport for the recycling process. Modern car crushers tend to employ hydraulics … Read more

An excited hush falls across the deserted tower block. Neighboring residents look on as the police helicopter overhead double-checks that the exclusion zone is clear. The countdown reaches zero and the button is pushed. An explosive shockwave ripples through 1,500 separate charges, shattering the supporting concrete columns. With surprising grace, the huge 24-storey tower block … Read more

Few other naked-eye astronomers have plotted the movement of planets quite as accurately as Danish nobleman Tycho Brahe. His observations of a new star in 1572 and the Great Comet of 1577 helped to shake off the Aristotelian belief that the planets and stars were unchanging and locked in ‘immutable’ celestial spheres. Brahe’s schooling began … Read more

Any two bodies that are gravitationally bound, such as Earth and the Sun, have five regions of gravitational stability. In these regions, the forces of gravity from the two bodies balance out, and anything located at these regions, known as Lagrangian points (or simply Lagrange points) will remain stationary. Lagrangian points are fascinating, and it … Read more

The age of the universe is calculated by measuring its rate of expansion and working backwards to the Big Bang. It was first estimated by American astronomer Edwin Hubble, whose initial calculation we have improved upon today. In 1929, Hubble realized the universe is expanding when he noticed the farther a galaxy was from Earth, … Read more

Throughout the year, Earth’s axis tilts slightly towards or away from the Sun, so that one hemisphere will have a longer day than the other, depending on which is more inclined towards our star. But every March and September, Earth reaches a point in its orbit where neither hemisphere is tilted towards the Sun, as … Read more

Astronomers use two impact hazard scales to describe the risks associated with Near Earth Objects (NEOs). The simpler Torino Scale runs from 0 to 10. Objects rated 0 are either highly unlikely to strike Earth, or too small to survive the passage into the atmosphere, while an object meriting a 10 would be a certain … Read more

Uranium is a metal of the actinide series: a group of large, radioactive elements, represented as an additional row on the periodic table. It is the heaviest of the naturally occurring elements and has 92 protons and 92 electrons. Like every element heavier than lead – which has 82 protons and 82 electrons – uranium … Read more

The active ingredient in pepper spray, capsaicin, comes from the chilli plant. Produced to protect the plant’s seeds from being crushed by the teeth of grazing animals, this molecule binds to TRPV1 receptors on the endings of pain nerves, causing them to fire and inducing a feeling similar to burning. Pepper spray is a concentrated … Read more

We all know water comprises just two chemical elements, oxygen and hydrogen, both of which exist as gases in Earth’s atmosphere. Making water should therefore be as simple as smashing the two together with enough force to overcome the energy barrier keeping them apart – right? However, this reaction produces a huge amount of energy, … Read more

The incredible geometric patterns may look artifi cial, but they are, in fact, the visualisation of how sound waves interact as they travel across a surface. The study of these figures is called cymatics, which derives from the Greek word ‘kima’ (wave) and was first coined by Swiss scientist Hans Jenny in 1967, but the … Read more

At California’s National Ignition Facility (NIF), 192 lasers are poised and ready to unleash four million joules of energy on their target: a pea-sized pellet of frozen hydrogen. Making up the world’s highest energy laser system, their goal is to create the intense pressures needed to initiate nuclear fusion – the reaction that powers the … Read more

Meerkats might not be the biggest animals on the African plains, nor appear to boast any particularly formidable weapons, like the rhino’s horn, or impressive skills, like the cheetah’s speed. Nevertheless, through a combination of hardy biology, smart tricks and a unique community spirit, these mammals have adapted perfectly to their harsh environment. They escape … Read more

Anyone who has ever spent the day at a beach will know that the sea is not static. Indeed, over 24 hours a shoreline can change dramatically as the gravitational interaction between Earth, the Moon and the Sun dictates the ocean tides. But are other large bodies of water on Earth subject to tides as … Read more

Also called sea cows, manatees might not immediately resemble your average land-based bovine, but they do share a number of their characteristics. They are bulky, generally peaceful creatures and spend a large proportion of their time grazing on plants; in fact, they’re the only marine mammal with an exclusively vegetarian diet. Surprisingly graceful in the … Read more

Antarctica is Earth’s coldest, driest and windiest continent, but many resilient life forms have adapted to survive the harsh environment. Among them is Earth’s tallest penguin, the largest mammal and the Antarctic icefish – the only bony animal with transparent blood. The coldest temperature ever officially recorded was on a high snow plateau in Antarctica, … Read more

In 2014 touchscreens will no longer be merely small, rectangular panels embedded into two-tiers of mobile electronic devices, but instead flexible, transparent and widely integrated screens found everywhere, from walls to tables and even food menus. Indeed, in 2013 Taiwan’s Polytron Technologies already managed to produce a completely transparent smartphone, equipped with a fully functioning … Read more