Karen Hill

Thermotropic liquid crystals makes a mood ring change colors. They’re little crystals that change molecular states when the temperature changes. When their molecular states change, the crystals’ ability to absorb light also changes, meaning the color you see will change, too. The ring picks up body heat from your finger, and transfers it to the … Read more

When the Sun makes you sneeze, it’s called a photic sneeze reflex, and it occurs in about a quarter of the population. What happens to convince your nose that the sun is an object that must be sneezed out of your nasal cavities? It’s simply a case of crossed wires, like hearing interference on your … Read more

After serious research into the matter, it’s now understood that it’s actually some of the lower-frequency sound vibrations involved in this action that trigger the aversion response, and not the squeaky higher ones you might suspect. But why do some people have this response? Some researchers say it might be a physiological throwback to the … Read more

People have been fascinated by this phenomenon of asparagus making your pee stink for eons. Why, even Ben Franklin had something to say on the subject. He wrote, “A few stems of asparagus eaten shall give our urine a disagreeable odor; and a pill of turpentine no bigger than a pea shall bestow upon it … Read more

A higher ratio of wastes to water turns urine a bright yellow color, which explains why the first urine in the morning is often quite a deep yellow. If your urine is a very faint yellow, it generally means you’re well hydrated. If your urine is dark, you’re probably dehydrated. Eating different types of food … Read more

Yes, most beans make us gassy and fart. Blame it on the oligosaccharides, or, if you prefer, the dog. Oligosaccharides are a special sugar found in beans and other fibrous foods like soybeans, cabbage, peas, and cauliflower. These sugar molecules are very large and are not digested by the small intestines, so they pass on … Read more

Perhaps you’ve noticed this when changing your cat box, but one of the main ingredients in urine is ammonia. This means that urine can act as a disinfectant. Ammonia is also used to take out the stinging and itching of insect, jellyfish, and anemone encounters. In our germ-conscious society, you may not be aware that … Read more

Farts are pretty flammable. Of the three main gases in farts—nitrogen, methane, and hydrogen—methane and hydrogen are both highly flammable. Nitrogen’s not. According to the statistics we found, over a quarter of the idiots who try lighting farts get burned. The rest are treated to a barely visible show of yellow and blue flames, as … Read more

Burps are produced when you swallow air. Normally, this can happen while eating and drinking, but it’s possible to build up air in the stomach through the regular, automatic swallowing that your body does to clear away draining saliva and mucus. The bubbles in carbonated drinks will often cause burps as well. But the digestive … Read more

For years we’ve heard there’s a fixed quantity of water we should drink every day. It turns out it was just a marketing ploy by companies that sell bottled water. We guess it goes to show that if you can’t trust people who’ll sell you a plentiful, virtually free substance for a buck-fifty a bottle, … Read more

First, a little explanation for those more refined readers among us: a “high-colonic irrigation” is a high-powered enema in which up to twenty gallons of liquid are pumped into your intestines a few pints at a time, with a really smelly liquid pouring out afterward. A few “alternative health” gurus claim that cleaning out your … Read more

Your armpits stink because bacteria love dark, wet places. You sweat there, creating moistness, and because your arm isn’t always raised —which would allow constant airflow, —bacteria begin to multiply. You don’t really stink, per se, it’s the excrement of the bacteria that stinks. The general advice here would be to have a shower as … Read more

The only thing at work in a deodorant is fragrance. It may be natural fragrances from oils, or it may be chemical perfumes, but when you use it, all you’re doing is masking the smell. An antiperspirant, however, contains aluminum or zirconium to block pores so sweat can’t escape from the sweat glands as easily, … Read more

Sweat glands and sebaceous glands are totally different. Sweat glands produce sweat, and sebaceous glands produce oils. Most of your sebaceous glands are located on your scalp and face. When something obstructs the regular release of sebum (fatty oil), it leads to painful and blocked glands, also known as acne.

Yes, hair oils are the same as body oils, both come from sebaceous glands on the scalp. Unfortunately, we end up washing most of them away before they have time to work their magic on our dried, cracked hair but hey, that’s why we have conditioner. Showering less often would work, except you end up … Read more

Hair conditioners work to detangle hair and don’t do much else except make you smell nice, but here’s what they’re doing when you put some in your hair. Have you ever looked at a strand of healthy hair under the microscope? It’s crackly, with a lot of crevices up and down the length of it … Read more

No, double-jointed joints are not different from regular joints, they’re basically the same thing. As a matter of fact, no joints are truly “double-jointed.” Instead, the joints and connecting muscles are merely more flexible and mobile, bending farther back than most people are capable of. Although some people are born with a greater range of … Read more

What we call a “funny bone” isn’t funny and it isn’t a bone. It’s a nerve called the ulnar nerve, which is entirely too exposed for its own good and yours. When it is hit, tingling, numbness, and pain strike the outer fingers on your hand and may take seconds or even minutes to subside. … Read more

It can be embarrassing when stomachs make noises, but they have their reasons; a lot is going on in there. When your stomach is empty, and there’s nothing for the stomach acid to do, it doesn’t just go away. It churns and produces gases as it bubbles and waits, impatient for you to feed it. … Read more

Hiccups are muscle spasms in the diaphragm and throat, and it happens to us at the worst times, when we least expect it. The large muscle at the bottom of your chest cavity sometimes spasms (as do most all of the muscles in the body, at one time or another). When this happens, air gets … Read more

Let’s blame Aristotle for the term meteorology. He was a smart guy who was right about a lot of things. However, he was wrong about meteors. He coined the term meteorology in 340 B.C. in a book called Meteorologica in which he laid out his ideas of weather. He believed that meteors were part of … Read more

Air pollution was a problem long before cars and trucks—in fact, long before the Industrial Revolution. No doubt the tens of thousands of fires used for cooking and heating often created lung-unfriendly environments in ancient cities. Wood smoke was bad enough, but things got worse as humans discovered other sources of heat. For example, London … Read more

Not even close. In 1272 King Edward I banned the burning of the notoriously smoky sea-coal under penalty of torture or death. Even after the king had the first offender put to death publicly, the law deterred no one. Few people could afford wood, so out of necessity they continued to burn sea-coal, and the … Read more

The sun emits light waves in all colors of the spectrum, with the wavelengths of each color vibrating at different rates. The reds and yellows have a long wavelength. Since they’re traveling in straighter lines from the sun to Earth, they are covering more ground with less chance of interference. As a result, fewer of … Read more

Well, don’t underestimate the time-of-day factor: for most humans, nearly everything looks better at 8:00 P.M. than at 5:30 A.M. However, in this case you’re right—on most days, sunsets are much more brilliantly colored than sunrises. It doesn’t make sense, since most of the same conditions are in place for each—a sun in a low … Read more

Clouds consist of millions of tiny water droplets. Light waves of all the colors bounce and reflect off and refract through the water droplets evenly, sending all of the various colors off in (more or less) equal measure. As you may remember from school, the “color” white is technically all of the colors mixed together. … Read more

Despite having a fluffy facade of unbearable lightness, clouds are actually pretty heavy things in the sky. Take even a small, fluffy cloud measuring a mere cubic kilometer. The water in that cloud would typically weigh about a million kilograms, about the same as 500 mid-size automobiles. So how does all that weight stay up … Read more

Cirrus clouds, those high, wispy-looking clouds you see on a clear day, are above 18,000 feet—about 3.5 miles high. The highest clouds ever recorded were just under 60,000 feet, or about 11 miles high, though the instruments used to measure such things are less than precise. To put this in perspective, Mount Everest is 29,035 … Read more

Cirrus means “curl of hair” in Latin. The four main types of clouds were all named in Latin, according to what they looked like to someone standing on the ground. Besides cirrus, cumulus. means “heap,” stratus means “layer,” and nimbus means “rain.” Why do clouds have Latin names? It’s just cooler that way.

There are several ways it can rain instead of snow even when the temperature is below freezing. It helps to think of the air— from clouds to ground—as a series of layers, each with its own temperature, and each with the ability to affect falling precipitation. For example, the cloud may be below freezing temperature, … Read more

Hail is not even the same thing as sleet. Not even close. Freezing rain, raindrops that freeze once they hit the ground—occurs only during wintry, subfreezing weather. Hail, on the other hand, almost exclusively falls during thunderstorm season between spring and early fall. Here’s how hail happens. When thunderstorm clouds gather together from heat and … Read more

Well, one rational theory on the origin of the phrase “raining cats and dogs” is that it’s just a comically overblown expression of hyperbole. However, other theories exist as well. Some believe it literally describes an actuality of the past. Here’s what we do know for sure. The phrase comes from England, and its first … Read more

Not just in Mexico, —it’s been raining frogs all over the world for a long time now, if you believe the reports. And not just frogs either, but fish, periwinkles, crabs, jellyfish, coins, worms, baby alligators, and even ears of corn. These are not just stories from the tabloids; some have even been reported in … Read more

Angry gods, of course. Haven’t you ever watched cartoons? Okay, it’s electricity, and it’s not that far removed from what happens when you rub a large, furry cat. Start with those tall, puffy cumulonimbus clouds that develop quickly as hot, moist air flies up into colder layers. The turbulence forces water vapor to move up … Read more

The speed of light is a lot faster than the speed of sound, about a million times faster, so lightning can often be seen before thunder is heard. Next time you’re in a storm, wait until lightning flashes, then begin timing the seconds until you hear thunder. Divide the number by five, and that’s about … Read more

The difference between thunderstorm warnings and thunderstorm watches is the same as a tornado watch and warning: A thunderstorm watch means that all the ingredients are in place to possibly create a severe storm. A warning means a storm of this magnitude has already been spotted, so take cover now! For more information, tune in … Read more

Lightning is an electrical charge trying to find its way into the ground. It will use whatever conduit it can to best accomplish that. Air doesn’t conduct electricity all that well. Actually, it’s pretty resistant, so when there are other alternatives, lightning will use them to make its way toward ground. The best thing to … Read more

No. It’s true that a car is a relative safe haven during a lightning storm, but it’s not because of its rubber tires. As a matter of fact, rubber offers no significant insulation whatsoever from lightning. Cars work as an okay shelter from lightning storms because the metal frame will tend to attract lightning and … Read more

Generally, your odds are 3,000,000 to 1 that you won’t get hit by lightning. But in lightning strikes, as in real estate, location is everything. If you’re a park ranger and spend most of your time outdoors, your odds of course will be higher than if you’re a practicing couch potato. If you get your … Read more

Yes. All rainbows are completely round. It’s just that we don’t usually see the whole rainbow because we’re standing on the ground and looking toward the horizon. Unless you’re in the air, or looking down from a mountain, you can usually just see the top part of a rainbow. The “bow” in rainbow refers to … Read more

If you’ve ever made bread dough by hand, you can imagine what a strain it would be to knead dough with your arms all day. About 6,000 years ago an unknown Egyptian baker took a tip from wine makers and tried using his feet instead of his hands to do the hard work. It worked … Read more

Most old phones including rotary phones would be compatible with today’s phone system. Basic phone technology hasn’t changed much in the last one hundred years, so that “candlestick phone” from the 1920s will work as fine as your cordless, and better in a power failure. The only thing you’d have to do is adapt the … Read more

Yes, phones used to have hooks. They were there to hold the earpiece. “What’s an earpiece?” you ask. Remember old movies where people held a bell-shaped thing to one ear while shouting into a cup-shaped thing on a boxy phone hanging on the wall? Well, the bell-shaped thing is the earpiece. Anyway, if someone’s earpiece … Read more

Most land line phones would work in a power failure, just not cordless ones unless there’s a battery backup system. The telephone network system provides its own power system through the phone lines, so that your basic corded phone will often work even when your lights won’t. It’s a pretty good system, but it gets … Read more

Chemical ice packs work kind of like magic, if you think about it: You break something inside and shake it, and suddenly the whole pack gets icy cold. What’s funny is that what’s inside is pretty basic stuff. You could conceivably make one yourself—all that’s in it is water and ammonium-nitrate fertilizer. Breaking the bag … Read more

Let’s start with the two basic principles that make modern refrigeration possible: The first rule you know already if you’ve ever inflated a tire using a hand pump and noticed that the pump was surprisingly hot afterward: Gases will heat up when you compress them. Conversely, gases cool down when you release pressure and allow … Read more

Sundials were and are not that accurate, alas. There were too many variables in sun positioning during the year to make sundials useful for more than a give-or-take-an-hour guess of the time. The quantum leap forward in time measurement took place in December 1656, when Dutch scientist, musician, and poet Christiaan Huygen invented the world’s … Read more

Most smoke detectors use an ion chamber that emits a steady stream of ions that get disrupted when smoke is present, setting off the alarm. Some smoke detectors use a photoelectric sensor instead that detects changes in a light beam when smoke hits it. Unfortunately, these are more expensive, and not as effective as the … Read more

Any liquid that expands in the heat and contracts in the cold would work, and you could use any of them inside a thermometer. The problem is finding a liquid that has a good workable range between its freezing and boiling points. Water, for example, has a freezing point of 32 °F (0 °C) and … Read more

Elementary science, my friend. Cold water is heavier, so it sinks to the bottom. The hot water rises to the top, which is also where you’ll find the outflow pipe, the one that goes to your hot water faucet. As a result, you’ll always be getting the hottest water in the heater. Most water heaters … Read more

Microwaves are radio waves with a very high frequency, which makes them very short, hence the “micro” in microwave. On your radio dial, you’d hear your microwave oven broadcasting at 2,500 megahertz, if your radio dial actually went that high. It doesn’t, 108 megahertz is the highest a standard radio picks up. A megahertz, by … Read more

You exceeded the liquid’s boiling point, and it exploded in the microwave oven, that’s what happened. Years ago, school teachers used to teach that water (unless pressurized) could never get hotter than its boiling point. That seemed true then, you put a pot on the stove, and it would bubble and boil furiously, allowing steam … Read more

Microwaves aren’t radiation, they’re radio waves, so microwaved foods never become radioactive in the first place. The way microwaves work is that they have a strong effect on water, twisting its molecules back and forth rapidly. As the water molecules rub back and forth against other molecules, they heat up from the friction. Luckily nearly … Read more

Metal in the microwave oven being dangerous is true enough that you’d want to avoid doing it. However, there are some loopholes. It turns out that some metal is worse than others. According to a physics professor at the University of Virginia, “Metal left in the microwave oven during cooking will only cause trouble if … Read more

Microwaves can pass through glass and plastic, but they can’t pass through metal. Strangely, they also can’t get through a hole that’s significantly smaller than their wavelength, so the fine metal mesh keeps them inside the oven, while letting some light out. In other words, your microwave oven is safe and your brain won’t fry … Read more

Both neon lights and fluorescent lights are long glass tubes with gas inside and an electrode on each end. Electrical currents pass through the gas from one electrode to the other, exciting the electrons enough that they emit light energy. The only significant difference between the two types of lights is the stuff that’s inside, … Read more

There’s a little bit of neon in the air we breathe, so yes, our atmosphere contains neon. You can extract it by using a process called adsorption. That involves superchilling the air at temperatures below —411 °F so it becomes a liquid. When you run the super cold liquid over charcoal, the neon molecules stick … Read more

Actually, saving energy by leaving fluorescent lights on all the time a myth that may have been true decades ago, when fluorescents required a hefty jolt to get them started. Nowadays, however, starting a fluorescent light takes only a small amount of extra electricity, so you’ll save electricity by turning the light off when it’s … Read more

Before we refute if windows get thicker at the bottom over years, let’s look at why some people have considered the idea plausible enough to make it the pernicious urban myth it has become. Their reasoning goes something like this: Solids and liquids have different molecular structures—the molecules of solids occur in regular patterns, while … Read more

Most glass is made of silica sand (silica, or silicon dioxide), with a little soda ash (sodium carbonate) and limestone (calcium carbonate) added to lower the sand’s melting temperature. Early humans got the idea for making glass after finding chunks formed by lightning strikes on the beach. These early humans originally cast it like metal … Read more

Making nearly perfect glass long eluded human ingenuity, as witnessed by the panes in old houses, in which imperfections in the thickness and surface create a subtle “fun house mirror” effect, distorting what you see outside. The ancient Romans never figured out how to make sheet glass for windows. They did try molding window glass … Read more

Although recent studies have shown that the brain can grow some new cells, you’d be wise to take good care of the ones you were born with. You can’t generate enough of the right kind to even consider riding your bike without a helmet, young man.

The old “we use only 10 percent of our brains” myth is so beloved by psychics, human potential gurus, and others who have made a cottage industry of hawking seminars and books. It’s not true. As it happens, you probably use all of your brain during a normal day, but not for every function. It’s … Read more

No, smarter people’s brains are not bigger and heavier than dumber people’s brains. There’s no apparent connection between brain size in humans and their intelligence. If that were the case, the average man would be 10 to 12 percent smarter than the average woman because men have larger brains by about a third of a … Read more

The part of the body that has the thickest skin is pretty much as you’d suspect. The soles of the feet and palms of the hands have the thickest layer of skin. After that, the back and nape of the neck are the thickest. The thinnest layer of skin is around the eyes, particularly the … Read more

Actually, your fingers and toes aren’t wrinkling at all but puckering from swelling. The thick outside layer of skin, called the stratum corneum, takes on excess water when saturated—sort of like when dried beans are soaked in water. The underlying skin and connective tissue around the stratum corneum doesn’t absorb water and therefore doesn’t swell … Read more

They’re called wisdom teeth because they’re the latest to arrive—when a person’s (presumably) older and wiser. The funny thing about our molars is that none of them form beneath any of the baby teeth. They develop only after our jaws grow big enough to make space for them. The problem arises when your jaw doesn’t … Read more

Other mammals do have what we call wisdom teeth, the molars that lie farthest back in the mouth. Often in humans, the jawbone is too small to accommodate these teeth, so they can’t break through the gums and become painfully wedged against the jaw and the other molars. In other mammals, however, their jawbones are … Read more

The opposite of cross-eyed is wall-eyed, but any kind of deviation from both eyeballs pointing straight ahead is called strabismus. The technical terms for these conditions are esotropia (cross-eyed) and exotropia (wandering eyes, or walleyed). Hypertropia is when one eye wanders up. About 5 percent of all children have some degree of strabismus, which most … Read more

Asians don’t actually have slanted eyes, —that’s an optical illusion, as it were. Folks from Asia actually have an extra fold in their eyelids called the epicanthic fold. It’s at the top of the eyelid and is elongated, sometimes extending beyond the eyelashes. Caucasian or African eyes have a slight, shortened fold where the epicanthic … Read more

An eyeball weighs about one ounce. You could send one in the mail for the price of a U.S. postage stamp. But make sure you mark it “Fragile.”

Yes, but the medical miracle of correcting blindness works better with those who’ve gone blind over the years, or those who were born almost blind—but not completely. There does seem to be a problem with suddenly getting sight if you’ve never had it before. Normally, the brain learns how to process visual information from the … Read more

In Europe and America, lefties make up 11 percent of the total population. And to answer your question, left-handed people are injured more often. Because they live in a world made for people who are right-handed, some recent studies have suggested that left-handed people are born with a weakened immune system and tend to have … Read more

Left-handedness is called Sinistrality. Right-handedness is called dextrality. It’s a sad case of right-handed bigotry that the word sinister comes from the name for left-handers, and dexterity from the name for right-handers.

The origin of the term southpaw reaches all the way back in time to, well, baseball. All baseball diamonds are created equal: the pitcher faces west, the batter faces east. This helps the batter survive a careening pitch by keeping the setting sun out of his eyes. It also means that the pitcher’s left hand … Read more

Sure, it happens all the time. The heart beats more than two and a half billion times in the average lifetime. In between each beat, the heart stops momentarily, meaning a total of twelve years of your life is spent with a stopped heart. Other than that, hearts can stop for a few minutes and … Read more

First, some background. The tip of the mammalian penis is called the glans. Although “glans” sounds a lot like “glands,” it actually has nothing to do with the production of hormones. Glans comes from the Latin word meaning “acorn.” It’s an odd sort of shape, isn’t it? One many of us have wondered about—, biologists … Read more

The first condom on record was made from a goat bladder by ancient Romans. But it wasn’t the first form of birth control. For at least 8,000 years, folks used coitus interruptus as a widespread and moderately effective form of birth control. It’s mentioned in both the Talmud and the Book of Genesis as a … Read more

It’s just more efficient that way. Nipples are one of the body parts that everybody gets issued early in life. They’re formed during the first fourteen weeks of development in the womb. The fact that everyone gets them sort of makes sense, since they begin growing before male or female hormones start flooding the fetus … Read more

Sure, there have been several experiments involving sex while in orbit. None of them, alas, have involved humans—at least, according to NASA. That makes it sound as if we don’t believe them. Frankly, we do, for a couple of reasons: Until recently, space trips have been relatively short—certainly not long enough for astronauts to start … Read more

No humans have floated away in space. So far that’s just the stuff of fiction and pop songs. As a matter of fact, all of the deaths to date have occurred during launch or reentry from outer space. The first to die was Vladimir Komarov in 1967. Several mechanical failures upon reentry into Earth’s atmosphere … Read more

No, astronauts can’t land on the dark side of the moon and here’s why. At the lunar equator, daytime temperatures can reach about 273 degrees Fahrenheit—a temperature that astronauts can tolerate in their space suits, although we’re sure they’d prefer a slightly cooler spot. At night when it’s dark, with no atmosphere to hold in … Read more

The predictable list of animals that have been sent into space includes dogs, monkeys, rats, mice, rabbits, and fish. No pigs, as of yet, but guinea pigs and pigtailed monkeys have all been put into orbit, as well as the eye lenses of pigs, cows, and sheep. Some not-so-likely animal crew members have included jellyfish, … Read more

The U.S. Space Command in Colorado Springs, Colorado, tracks about 10,000 objects or pieces of space junk in low-Earth orbit (300 to 1,200 miles up), and most, if not all, of these are man-made. They consist of about 100 space probes, 3,000 satellites (functional and not), and around 6,000 bits and pieces: lumps and chunks … Read more

Multiply your weight by 2.4. That’s how much you weigh on Jupiter. For the sake of clarity, let’s say you weighed an even 100 pounds. On Jupiter, you’d weigh about 240. Multiply your same 100 pounds by .38 and discover that on Mercury you’d be about 38 pounds. On the moon (multiply by .17), about … Read more

Planetary rings, found only on the outer planets, consist of pieces of ice and dust. In 1977 it was discovered that there were, indeed, rings around the planet Uranus. This was a surprise, as the rings are so dark that they’d been completely invisible up until that point. What made it possible to detect them … Read more

The moon has over 30 thousand billion craters that measure at least a foot wide, half a million of those with diameters over a mile. That’s a lot of holes and pockmarks, and there are a lot of names that have been given to moon craters over the years. Alas, “Scooby Doo” isn’t one of … Read more

New planetary moons in the solar system are discovered all the time. At this writing, Jupiter wins, hands down, with a total of thirty-nine —sixteen well-known moons and some lesser-known, more recently discovered moons. All of Jupiter’s major moons are named after mythological characters. Jupiter’s four large moons are Io, Europa, Ganymede, and Callisto. Jupiter’s … Read more

Objects in space do get confusing sometimes, so let’s see if we can clear things up a bit. Asteroids, sometimes called minor planets or planetoids, are small (in comparison to larger planets) planet like rocks that orbit the sun. They usually reside in the Asteroid Belt, which lies between the orbits of Mars and Jupiter. … Read more

At the equator, Earth spins at about 1,070 miles per hour. As you move north or south from there, the speed slows. Exactly at the poles—Earth’s axis points—the spin is much slower. Picture a record spinning. If you placed a toy at the center, then moved it an inch away from the center, then two … Read more