Science

It’s all in the chemicals. Baking soda (aka bicarbonate of soda) is a single chemical: pure sodium bicarbonate, whereas baking powder is baking soda combined with one or more acid salts, such as monocalcium phosphate monohydrate, dicalcium phosphate dihydrate, sodium aluminum sulfate, or sodium aluminum phosphate. Now that I’ve warmed the hearts of chemistry fans … Read more

Let’s look at how chocolate is made. Cacao beans, which are really seeds, are found inside melon-shaped seedpods attached directly to the trunk or thick branches of the tropical cacao tree. The beans are first separated from the pulpy mass inside the pod and allowed to ferment, usually by piling them up in heaps and … Read more

I know what you’re thinking. The corn that you bought at the farmers’ market the other day wasn’t really “as sweet as sugar,” as the vendor promised, was it? “Sweet corn” does indeed contain more sugar than “cow corn,” but even in the new sugar enhanced and super sweet varieties it’s precious little compared with … Read more

The word caramelize is used for the browning of a variety of foods, but strictly speaking, caramelizing means the heat-induced browning of a food that contains sugars, but no proteins. When pure table sugar (sucrose) is heated to about 365ºF it melts into a colorless liquid. On further heating it turns yellow, then light brown … Read more

Why don’t you try it? Add two cups of sugar to one cup of water in a saucepan and stir while heating slightly. You’ll see that all the sugar will dissolve. One of the reasons is very simple: Sugar molecules can squeeze into empty spaces between the water molecules, so they are not really taking … Read more

Cane syrup is simply clarified sugar-cane juice, boiled down to a syrup in much the same way maple syrup is made by boiling down the thin, sucrose-rich sap of the North American sugar maple and black maple trees. Black birch trees also have a sweet sap that can be boiled down into a syrup. Treacle … Read more

The “sulphur” in sulphured molasses is a good starting point for understanding several interesting aspects of food chemistry. Sulphur is the old-fashioned spelling for sulfur, a yellow chemical element whose common compounds include sulfur dioxide and sulfites. Sulfur dioxide gas is the choking, acrid odor of burning sulfur and is reputed to pollute the atmosphere … Read more

More than half of the sugar produced in the U.S. comes from sugar beets, misshapen, whitish-brown roots that resemble short, fat carrots. Sugar beets grow in temperate climates, such as in Minnesota, North Dakota, and Idaho in the U.S., and in much of Europe, whereas sugar cane is a tropical plant, grown in the U.S. … Read more

There’s a quick fix that gives temporary results, long enough for you to measure some out for a recipe, and there’s a more time-consuming but longer-lasting fix that will restore your sugar to its original, manageable form. But first, what makes brown sugar turn hard in the first place? Loss of moisture. You didn’t reseal … Read more

Good try, but you used the wrong sugar. Ordinary table sugar is “granulated,” meaning that it consists of individual granules or grains, each of which is a single crystal of pure sucrose. But when pulverized into a fine powder, sugar tends to pick up moisture from the air and cake. (Techspeak: sugar is hygroscopic.) To … Read more

This nonsensical claim is a mystery to me. It seems that some people take the word refined as an indication that we humans have somehow defied a law of Nature by having the audacity to remove some undesirable materials from a food before eating it. White sugar is just raw sugar with those other materials … Read more

What health-food stores call raw sugar isn’t raw in the sense that it is completely unrefined. It’s just refined to a lesser degree. From the dawn of history, honey was virtually the only sweetener known to humans. Sugar cane was grown in India some three thousand years ago, but it didn’t find its way to … Read more

In a word: fuel. When a runner loads up on “carbs” before a race, it’s like a car filling up at the gas station. Carbohydrates are a class of natural chemicals that play vital roles in all living things. Both plants and animals manufacture, store, and consume starches and sugars for energy. Cellulose, a complex … Read more

There’s no such thing as a stupid question. This is perhaps the most profound question in all of science. Nevertheless, it does have a fairly simple answer ever since a genius by the name of Josiah Willard Gibbs (1839–1903) figured it all out in the late nineteenth century. The answer is that everywhere in Nature … Read more

You think you’ve got trouble? In China there are 2-million-year-old accumulations of dust (called loess by geologists) that are more than 1,000 feet (300 meters) thick. But it’s not due to sloppy housekeeping. The dust has been swept up by winds from the Gobi Desert. In certain locations where the winds die down, they drop … Read more

It’s one of life’s little ironies. Sailors do hard, often dirty work, yet with all that water around they can’t bathe or wash their clothes with soap. Not with ordinary soap, anyway. There is a special soap called “sailors’ soap” that works in salt water. But first let’s see why the ordinary stuff doesn’t. It … Read more

It’s because of a time and space-saving shortcut that’s used in the final stage of the manufacturing process. Aluminum, like all metals, is malleable; that is, it will squish when enough pressure is applied. That’s in distinction to most other solid materials, which will crack under pressure. So metals can be rolled out into extremely … Read more

It’s one of those coincidences that aren’t really accidental when you dig a little deeper. As we’ll see, the good-guy and bad-guy properties both stem from the fact that nitrogen gas is made up of molecules that strongly resist being torn apart. First, the fertilizer role. Every gardener knows that nitrogen is one of the … Read more

What you have is an ionization-type smoke detector. It detects smoke by the fact that smoke interferes with air’s ability to conduct a tiny electric current. Under ordinary conditions, air doesn’t conduct electricity at all; it’s an excellent insulator. That’s because the nitrogen and oxygen molecules in the air have no electric charge of their … Read more

For the same reason that your flashlight needs two batteries. A set of zinc and copper metals will move electrons with only so much oomph. That’s because there’s only a certain amount of difference between the electron-holding powers of zinc and copper. But if you need more electron-moving force, to light a bulb, for example, … Read more

“Natural energy” is a favorite buzz-phrase of hucksters and kooks pushing everything from arthritis cures to communication with the dead. There seems to be this idea that “natural energy” is everywhere, to be plucked out of the air by such magic trinkets as copper bracelets (for arthritis) or by those crystal amulets that you wear … Read more

It isn’t difficult, and it works with Pepsi too. It’s based on the fact that a can of the diet drink is slightly lighter than a can of the regular drink. Regular Coca-Cola is sweetened with sugar (sucrose) or corn sweeteners, which are other sugars, usually fructose, maltose and/or glucose. Diet Coke, on the other … Read more

Judging by what we see on television, you’d think that the major role of champagne in American culture is to hose down Super Bowl winners in locker rooms. Somewhat younger children do the same thing with soda pop, making sure to shake the bottle well before moving the thumb partially aside on the top in … Read more

An ollie, is named after its inventor, Allen Ollie Gelfand. Gelfand was one of a number of southern California surfers in the late 1950s who just couldn’t wait for good surf to come up and decided to surf the sidewalks. That’s what started the skateboard craze. An ollie is a jump into the air without … Read more

Your clothes get wrinkled because you insist on putting them on a warm, moist, moving body. If you were cold, dry and motionless, you’d have no problem. No clothing problems, anyway. It’s heat and moisture that put the wrinkles in, and it’s heat and moisture that are going to get them out. Dry, cold pressing, … Read more

One good film deserves another, so I’ll borrow my answer from a famous line in the 1967 movie The Graduate: “One word: ‘plastics.’” It’s mainly the plastics in your car that produce the coating on your windshield. Remember how your car smelled when it was brand-new? It smelled brand-new. A new car’s smell is a … Read more

One obvious factor is that your old tires may have been pretty smooth, and smoother tires will be quieter. Tire noise depends on the tread pattern, the roughness of the road and the roundness of the tires. Really, tires can be out-of-round, and the high spots will thump on the road during every revolution. But … Read more

If there is one statement that will make you a passionate believer in molecules, it’s this: Rubber stretches because it is made of stretchy molecules. A rubber band stretches because each of its molecules, all by itself, is built like a miniature rubber band. Rubber molecules are shaped like long, skinny worms, all coiled and … Read more

It doesn’t work like a chalkboard eraser, which wipes an accumulation of chalk off a smooth surface. Paper isn’t that smooth and a pencil mark isn’t all on the surface; most of it is embedded among the paper fibers. If you look at a pencil mark under a microscope, you’ll see that it’s not continuous; … Read more

You’ve put your finger on the most flagrant example of figures that lie, with the possible exception of breast implants. Let’s take a look at some statistics. From 1994 to 1997, the average number of shark attacks per year in U.S. waters was thirty-three. In the same four years, the average number of fatal airplane … Read more

It’s not the rain itself that you smell, but just about everything else. Almost everything smells a little stronger when it’s about to rain. Stormy weather is usually preceded by a drop in atmospheric pressure, or what the TV weather people like to call “barometric pressure.” (Is that what you feel when you’re struck by … Read more

Your car is a box of homemade weather, produced by your air intakes, your heater, your air conditioner and your passengers. But sometimes, because of your passengers’ irrepressible habit of breathing, the car fills up with a lot of water vapor and some of it condenses onto the cold windshield, fogging it up. What do … Read more

It’s usually more humid in the summer because there’s more water vapor available. I don’t mean that the oceans, lakes and rivers somehow expand in the heat. (Well, maybe a tad.) More precipitation? Perhaps. But it’s not the amount of water itself; the humidity can be quite low over the middle of the ocean. What … Read more

This is one of those questions that seems so natural that we forget to ask them. But that’s what I’m here for: to make you wonder about things you take for granted, and then to replace your complacency with the smugness of knowing. The water in your hair or clothes must first be converted from … Read more

Meteorologists love to tell us the dew-point temperature, even though few of us know what it is and even fewer of us care. But as long as I’m this deep into water vapor, I might as well explain that too. The dew point, or dew-point temperature, is the temperature below which the liquid-vapor balance of … Read more

Chicken Littles who fear drowning in air are forgetting that “humidity” is purely relative. Everybody goes around talking about “the humidity” as if it’s something absolute, but it’s really the relative humidity that they’re talking about, relative to some maximum, but still small, amount of water vapor in the air. And mind you, that’s vapor, … Read more

The cloudiness is a mass of tiny air bubbles, air that was dissolved in the water and expelled when the water froze. You can see the individual bubbles through a magnifying glass. There is always some air dissolved in any water that has been exposed to, well, the air. For this, the world’s fish are … Read more

Absolutely nothing would happen, as far as you would be able to tell. The ice and the water would dwell in peaceful coexistence. But down at the molecular level, a chaotic dance would be going on. Zero degrees Celsius (32 degrees Fahrenheit) is indeed both the freezing point of liquid water and the melting point … Read more

Liquids do get somewhat thicker as they are cooled, and because all glass was once a liquid while it was hot and being formed into shape, some people like to think that it gets thicker and thicker as it “supercooled,” until it gets so thick that it acts like a solid. Well, the truth is … Read more

Detergents aren’t soap, although soap is a detergent. The word “detergent” simply means a cleansing substance, from the Latin detergere, to wipe off. After more than two thousand years of using soap, which is easy to make by boiling up wood ashes with animal fat (don’t you wonder how that discovery was made?), humans finally … Read more

The stuff in the dryer sheet happens to be good at both jobs. You can obtain the static-elimination function all by itself as a liquid in a spray can, so you can de-static your clothing even while you’re wearing it without your having to, DO NOT TRY THIS AT HOME!, climb into the dryer. The … Read more

You’re lucky you asked that question today, because today is bargain day. I’m going to give you four answers for the price of one. It’s not because I’m feeling generous, but because I can’t make up my own mind about which one to believe. To my knowledge, the National Science Foundation has not yet funded … Read more

For years, people have observed this phenomenon without giving it a second, or even a first, thought. Hundreds of less-than-fastidious, coffee sipping scientists have probably glanced at the ring, mumbled something about surface tension and told their lab assistants to clean it up. But it wasn’t until 1997 that six scientists at the University of … Read more

That’s not why the Panama Canal has locks. The locks are there for the purpose of lifting ships over the hump of land known as the Isthmus of Panama. To get over that hump, the ships have to be floated upward 85 feet (26 meters) above the entrance ocean and then lowered back down into … Read more

When you say “salty,” you’re undoubtedly thinking of sodium chloride, common table salt. But to a chemist, a salt is any member of a large class of chemicals, and there are dozens of them in the oceans. To put the word “salt” in perspective, please indulge me in a one-paragraph chemistry lesson. A “molecule” of … Read more

That’s a common belief that just doesn’t hold water, so to speak. First of all, the ocean’s surface isn’t exactly what you’d call a mirror. And second, how come it’s a much darker blue than the sky? No, the world’s oceans really and truly are blue, many different shades of blue (ask any sailor), depending … Read more

It’s the one substance that is indispensable to all living things. It makes up more than half of our own body weights. It is the most abundant chemical on Earth, with more than a billion billion tons of it covering 71 percent of the planet’s surface and probably another billion tons in those little plastic … Read more

It isn’t. Satellites and space shuttles do indeed get cold up there, but it’s not because it’s cold up there. First of all, there’s really no such thing as cold, no matter what the penguins tell you. Cold is a linguistic concept, not a scientific one. Our caveperson ancestors needed a word for “not hot,” … Read more

Yes, but only once in a great while. There has to be exactly the right kind of smoke or dust in the air. It happened most spectacularly in 1883, when the Indonesian volcano Krakatau blew its top, spewing dust all around the globe. The bluest moon since Krakatau was caused by a series of forest … Read more

There are two answers: No and Yes. The No answer: The expression “when the moon turns blue” was used for hundreds of years to mean “when hell freezes over” or “fat chance.” “Blue moon” first appeared in print in the nineteenth century, but was probably used even before that because it’s a quirky idea and … Read more

It’s easy to fool yourself into thinking that the moon is bigger when it’s full, and that it therefore pulls on the oceans more strongly to make higher tides. But the moon is always the same size and distance away as it circles Earth. It is just lit up differently by the sun at different … Read more

Whenever someone pompously proclaims that the ocean’s tides are caused by the moon, everybody mutters, “Uh, okay,” and goes away just as puzzled as before. “It’s the moon” is a cop-out, because a real explanation requires a lot more than that. Ocean tides are the net result of several forces produced by motions of the … Read more

Sounds odd, doesn’t it? Either it’s the most colossal coincidence that ever occurred, or there’s something real fishy going on. Well, even the fishiest-seeming coincidences can have rational explanations. Your first guess might be that the moon isn’t spinning on its axis the way Earth is, and that it just goes around us, maintaining the … Read more

For much the same reason that stars twinkle, except that there are enough light rays coming from the object that no matter how much they scatter, some of them will always be reaching your eyes. So there’s no actual twinkling. When you look down the road on a hot day, you may see shimmering “lines … Read more

The answer that you see everywhere is that the twinkling is caused by turbulence in the atmosphere, which distorts the light coming from the star. But that doesn’t explain why “atmospheric turbulence,” whatever that is, should distort light in the first place, or where the on-and-off blinking effect comes from, or why only stars, but … Read more

Practically everybody has noticed this oddity at one time or another. When the moon is low, near the horizon, it looks huge compared with how it looks a few hours later when it is higher overhead. The effect is especially noticeable when it is a big, beautiful, full disk, a full moon. But you can … Read more

It depends on how far you are from the lightning. The closer you are, the higher the pitch of the sound you hear; the farther away you are, the lower the rumble. First, we have to remind ourselves of what thunder is. A stroke of lightning is extremely fast; it occurs with what might be … Read more

There’s a lot of nonsense out there about sonic booms. The Columbia Encyclopedia 5th edition (1993) says, “An object such as an airplane generates sound. When the speed of the object reaches or exceeds the speed of sound, the object catches up with its own noise” (I wish some politicians would do that), which causes … Read more

The crack of a bullwhip is actually a miniature sonic boom, produced because the tip of the whip is traveling through the air faster than the speed of sound. When the cat master snaps his whip sharply, he’s putting a great deal of energy into the handle end. That energy has no place to go … Read more

You’d get an exceedingly clean vacuum. But seriously, I don’t know why you’d want to imagine a thing like that, because there is nothing cleaner than a true vacuum; it is the epitome of nothingness. I’ll assume, however, that you ask the question out of scientific curiosity, rather than because it’s funny. What is a … Read more

Sorry, but yes. Not actual fragments, but individual molecules, molecules that have evaporated from the “stuff” and have floated through the air to your nose. But don’t get sick at the thought. It takes only an incredibly small number of molecules to be detected by humans as an odor. And the molecules aren’t even molecules … Read more

Every radioactive, or unstable, atom has a certain probability of disintegrating within a certain period of time. Some kinds of radioactive atoms are more unstable than others and have higher probabilities of disintegrating. We can’t tell when any single atom will disintegrate, but averaged over the zillions of atoms in even a minute speck of … Read more

Radiocarbon dating won’t help you to determine the age of anything that is still alive, such as a twelve-year-old posing as a twenty-five-year-old in an Internet chat room. It’s is useful for determining the ages of plant or animal matter that died anywhere from around five hundred to fifty thousand years ago. Ever since its … Read more

Probably not, if you mean making electricity from solar panels. There certainly is lots of sunshine, but capturing it and converting it efficiently is the problem. Let’s do the arithmetic. Every day, the sun shines down upon the surface of Earth an amount of energy equal to three times the world’s annual energy consumption. That … Read more

Absolutely. And during the autumnal equinox as well. And on Tuesdays in February, and anytime during the fourth game of the World Series when the count is three and two on a left-handed batter. Get the picture? The point, of course, is that equinoxes have nothing whatsoever to do with balancing eggs. But old superstitions … Read more

It’s just another one of those urban legends, probably started by an overenthusiastic physics teacher. But it’s based upon a grain of truth. Moving fluids such as air and water are slightly affected by Earth’s rotation. The phenomenon is called the Coriolis effect, after the French mathematician Gustave Gaspard Coriolis (1792–1843), who first realized that … Read more

Boy, you must really want to lose weight. Yes, you’d weigh very slightly less. You’re probably thinking that your weight is a consequence of Earth’s gravitational pull on your body, and that if you’re below the surface gravity has already done part of its job, so there is slightly less pull left. Well, there is … Read more

The riddle part is that polar bears live at the North Pole, not the South Pole. Furthermore, a polar bear at the equator wouldn’t be a polar bear, would he? He’d be an equatorial bear. But let’s take the question at face value; namely, will a bear, or anything else, for that matter, weigh less … Read more

No, even though they’re a lot higher and moving a lot faster than an airplane, the situation is still the same. To them, Earth’s surface appears to be “moving backward” at their speed of 18,000 miles per hour (29,000 kilometers per hour), just as it appears to you when you’re in a car or an … Read more

Because even when you’re flying off to a remote island to get away from it all, you can’t escape being part of “it all.” Your airplane is attached to Earth almost as tightly as the mountains below are, except that the airplane is (we hope) at a higher altitude. Your pilot would be the first … Read more

No, it’s because Earth’s rotation is a uniform, unvarying motion, and we can feel only changes in motion (Techspeak: acceleration). Any time a moving object is diverted from its motion, either by a change in its direction or a change in its speed, we say that it has experienced an acceleration. Acceleration doesn’t just mean … Read more

The South Pole, where the average temperature is about 56 degrees below zero degrees Fahrenheit (−49 degrees Celsius). At the North Pole the average temperature is a relatively balmy 20 degrees below zero (−29 degrees Celsius). Antarctica is actually a continent, with the ice and snow lying on top of a huge land mass, whereas … Read more

The air does keep getting colder, by an average of about 3.6 degrees Fahrenheit for every thousand feet (6.5 degrees Celsius per kilometer) , up to around 33,000 feet (10,000 meters) above sea level. That’s just a bit higher than the cruising altitude of large commercial jet aircraft. You may have heard the airliner’s captain … Read more

Obviously, because it’s always colder up there. But why is it always colder up in the mountains than down at the seashore? After all, doesn’t hot air rise? Shouldn’t it therefore be hotter up there? There’s certainly plenty of hot air in equatorial Tanzania, but Kilimanjaro, which thrusts its peak 19, 340 feet (5,895 meters) … Read more

It’s pretty hard to look inside that steel tank and see how much propane is left before you fire up the grill, isn’t it? Not all grills have pressure gauges. But hardware stores sell an ingenious little indicator that looks like a strip of plastic because it is. You stick it onto the outside of … Read more

People say heat rises because they’re speaking carelessly. The statement is just a lot of hot air, because heat doesn’t rise. What they mean to say is that hot air rises. Heat is one of many forms of energy; it is energy in the form of moving molecules. But it’s meaningless to say that any … Read more

Because the center of the planet is the center of Earth’s gravity: its center of gravity. You’ve heard the expression “center of gravity” before, and now’s your chance to understand what it really means. But first, what is gravity, or, more properly, gravitation? Gravitation is one of the three fundamental forces in Nature. (The other … Read more

This question is as old as electric power itself. It has been asked almost as often as “Do you love me?” and with equally unconvincing replies. The common answer, “The birds aren’t electrocuted because they’re not grounded”, doesn’t get to the root of the question. Does everyone who walks away after that explanation really know … Read more

Electric current is measured in amperes. An ampere is a huge unit of electric current, equivalent to 6 billion billion (6 followed by 18 zeros) electrons passing by every second. So you often hear talk of milliamperes or milliamps,  thousandths of amperes. One milliamp passing through your body will cause a mild tingling sensation. Ten … Read more

Voltage in itself isn’t dangerous. A 10,000–volt shock can be no more disturbing than a pinprick, but you can get a serious jolt from a 12–volt automobile battery. What’s dangerous is the amount of electric current that flows through your body as a result of the voltage. A current of electricity, as you undoubtedly know, … Read more

Unfortunately, no, for several reasons. First of all, the world’s supply of air conditioners and refrigerators isn’t anywhere near what you might think by looking around your neighborhood. But even if every citizen of the less-developed nations were privileged to enjoy cool bedrooms and frozen pizzas, the amount of available coolth wouldn’t amount to an … Read more

Light a match and, while it’s burning, twist it into a variety of positions. The flame keeps pointing unerringly upward, regardless of the orientation of its fuel. How, indeed, does it “know”? You are well aware that hot air rises. A flame, whatever it is, must therefore be carried upward by the rising current of … Read more

Yes, there is a hottest possible temperature. But let’s start off at merely warm and gradually turn up the heat. Heat is the energy that a substance contains within itself, due to the fact that its atoms and molecules are moving. But temperature is a man-made concept, invented so that we can converse among ourselves … Read more

They are indeed strange numbers for such common, everyday goings-on as the freezing and boiling of water. We’re stuck with them because a German glassblower and amateur physicist named Gabriel Fahrenheit (1686–1736) made a couple of bad decisions. Gadgets for measuring temperature had existed since about 1592, even though nobody knew what temperature was, and … Read more

Assuming that you haven’t forgotten to pay your gas bill, it’s because porcelain tile conducts heat better than that cozy bath mat does, even though they’re at the same temperature. It’s a common experience that certain things feel colder than others. People talk about “cold steel” as if the blade of a sword were somehow … Read more

Heat is energy. What kind of energy? It’s not electrical energy or nuclear energy or the kind of energy that your car has as you barrel down the highway. It’s the energy that an object contains within itself, because the particles that it’s made of, its atoms and molecules, are actually vibrating and bouncing around … Read more

If Tucson was twice as hot as Miami, it certainly wouldn’t be 160 degrees Fahrenheit (71 degrees Celsius). But that’s not because 160 degrees is too hot; it’s not hot enough. The temperature that is “twice as hot” as 80 degrees Fahrenheit, believe it or not, is 621 degrees Fahrenheit! Here’s what’s going on. First … Read more

Everything is hot. That is, it contains some heat. And as a consequence, it has a temperature. Even an ice cube contains heat. “Hot” is strictly a relative term. Heat is the ultimate form of energy, the form into which all other forms ultimately degenerate. There is energy of motion (Techspeak: kinetic energy), there is … Read more

Your question may sound silly to those who haven’t heard about it before, but chomping on those little candies really does make flashes of light. It may not help you at all to know that the phenomenon is called triboluminescence, but there, I’ve said it and done my duty as a scientist. Life Savers, it … Read more

Mirrors are the best reflectors of light that human ingenuity has been able to devise. Notice, however, that the light is reflected only from the backing of the mirror, after passing through the front layer of transparent glass. What is there about the backing that makes it such a good reflector? It’s a thin, smooth … Read more