Karen Hill

If the hot water tap in your showers start out fast then slows down to a trickle, it sounds like you have a defective washer, that rubber disk within the faucet that helps stop the water from flowing when you turn off the tap. Although the washers in both faucets can erode with time, the … Read more

Only you can test this one out, and find out if taking long showers would save you more water taking a bath. Plug your tub while showering, and see how high the water level is when you’re done. In general, a shower usually uses 10 to 15 gallons of water, while a bath usually takes … Read more

Better yet, we can give you an account from the first century B.C., written by Marcus Vitruvius Pollio, a Roman architect, engineer, and writer: In the case of Archimedes, although he made many wonderful discoveries of diverse kinds, yet of them all, the following, which I shall relate, seems to have been the result of … Read more

As it turns out, fluoride helps prevents tooth cavities in at least three ways. Science has known for a while that fluoride acts as a building block for teeth. Fluoride supplements, whether in drinking water or vitamins, help build stronger enamel in kids’ teeth before they even emerge from the gums. After the teeth emerge, … Read more

There are good reasons for using soap and shampoo for specific purposes. Soap cleans by using two methods. First, the fat in soap seeks out and surrounds dirt. The other substances in soap cling to water and help to wash away the fat and dirt molecules. But soap doesn’t work well on hair. Because soap … Read more

Marketing is the reason vitamins are put in shampoo. Because they make the shampoo sound like it’s more than just expensive glorified dish detergent. Although a lot of shampoo brands imply that the various vitamins they put in their products help make hair healthy and shiny, the truth is that vitamins can’t do much of … Read more

From a bacterial standpoint, it takes about twenty seconds for the germs and dirt to be picked up and washed away. Then there’s the case of why Ivory soap floats. Ivory soap floats because of air. They whip the soap, allowing air pockets to get into the mixture before it solidifies. As with a flotation … Read more

Actually, no one’s really sure how Rogaine makes your hair start growing again. What we do know is that it can’t make hair suddenly start growing after years of not growing. Because of this, it’s most effective on people who have just begun to notice a little bit of thinning. On most people, after about … Read more

People rode around in gliders before the Wright brothers were even born. In 1849 British engineer George Cayley built a glider that he tested by flying it like a kite. It had enough lift to carry a small boy briefly into the air, but it still wasn’t large or maneuverable enough to fly untethered. Finally, … Read more

A lot of people did think about adding an engine to a glider before the Wright brothers. For example, in 1843, William Samuel Henson wrote an article in Mechanics Magazine that proposed an “Aerial Steam Carriage” that would use a steam engine to drive a propeller in a fixed-wing aircraft. The problem wasn’t a lack … Read more

Designers of the B-2 Spirit stealth bomber say that they used radar-absorbing surfaces and a weird shape to outsmart radar systems. However, the more complicated and more disturbing answer is that the much-ballyhooed stealth design works only against a certain class of radar, and that the planes can be detected by newer radar systems. As … Read more

It’s an old childhood dream, isn’t it? Getting together enough helium balloons to “slip the surly bonds of earth” and glide peacefully over the rooftops. Well, that was Larry Walters’s idea as well. On July 2, 1982, the North Hollywood truck driver tied forty-five weather balloons to a lawn chair outfitted with a pellet gun, … Read more

The ancient myth of Daedalus and Icarus notwithstanding, it wasn’t until 1977 that a human-powered airplane managed to go any significant distance. Called the Gossamer Condor, the plane was designed by a California-based engineer named Paul MacCready. MacCready built the plane in order to collect on a long-standing award that British industrialist Henry Kremer established … Read more

If you’ve got a fear of flying and an active imagination, your mind can generate vividly horrifying scenes: ball lightning rolling down the aisle, shorting out laptops and cell phones, electrocuting passengers, overcooking the chicken It la king, that sort of thing. It probably doesn’t help to hear that lightning strikes airplanes more often than … Read more

A lot of nervous fliers have come under the impression that passenger jets will pretty much fall out of the sky if all the engines fail. The truth is that large planes can glide about as well as small ones. In fact, sometimes while landing a pilot will put the engines into idle and let … Read more

Increasing temperature or altitude can make a plane fly less efficiently by decreasing the overall density of air. The heat wouldn’t make the plane unable to fly, but it could increase the distance the plane needs to lift off and reach a good altitude. That could be a problem when taking off on a short … Read more

Planes on aircraft carriers use a technology that was perfected in the days of chariots and togas: the catapult. Under the deck of the carrier are two huge cylinders that measure more than 150 feet long. The cylinders, connected to a launcher, build up a great deal of pressure as they’re filled with steam diverted … Read more

While planes occasionally make an emergency landing on a freeway, there isn’t (and never has been) any such policy. “As with Dracula, it is very difficult to put a stake through the heart of this ‘fact,’ ” writes Richard F. Weingroff, an information liaison specialist for the Federal Highway Administration’s Office of Infrastructure. “It’s like … Read more

Well, it’s really quite clever in a low-tech sort of way. Most cars these days have a rearview mirror that deflects headlights when you tilt it. Picture a sheet of glass that isn’t the same thickness all the way through, but instead is cut at an angle so its top is thicker than its bottom. … Read more

You’d think it would take twice as far to stop a car going 60 mph than one going 30, but in fact it’ll take about four times as far—, roughly 180 feet at 60 mph, versus 45 feet at 30 mph. It’s an illustration of the principle that as you increase speed, your momentum (and … Read more

Wham-O, the company that brought the world the Superball, starts with a good, bouncy rubber—in this case, Zectron, which is Superball’s trademarked name for the synthetic rubber polybutadiene with some sulfur added for reinforcement. They take that and add a whole mess of pressure when they mold the ball. How much pressure? The company says … Read more

Well, in a sense there’s only one way to solve a Rubik’s Cube, but according to the Rubik’s Cube official Web site, there are about 4.3 times 10 to the 19th power, or 43,252,003,274,489,856,000, possible combinations. With so many possibilities, you’d think it would be a lot easier!

Mathematically, there are 2,598,960 five-card hands possible with a standard fifty-two-card deck in Poker. But that’s child’s play, considering there are 635,013,559,600 possible hands in a game of bridge. Still, these can’t hold a candle to chess: a mathematician once calculated that the first ten moves in a game could be played in 170,000,000,000,000,000,000,000,000 different … Read more

Here’s how it works: the oily extracts of the smells are placed inside really tiny bubbles of plastic, —millions of microscopic bubbles. How do they do this? By emulsion, —the mixing of oil and water. When they furiously mix the extracts with water, the oil is broken up into very tiny droplets, at which point … Read more

Most of us have an inexplicable fascination with bubbles. Even Mark Twain once noted, “A soap bubble is the most beautiful thing, and the most exquisite in nature. I wonder how much it would take to buy a soap bubble, if there was only one in the world.” Fortunately for us, there’s not. Here’s a … Read more

It would be cool if the story of the Slinky went back to the ancient Phoenicians, or Thorg, a druid from the Iron Age who discovered the property of a metal coil on stairs, but alas, Slinky’s history is shorter than that. It was during World War II that a marine engineer for the U.S. … Read more

First of all, a lot is owed to the stairs (or stack of books, or shelves) themselves. If the stairs you used were taller, the Slinky would flip over and end up rolling the rest of the way down. If the stair were shorter, the initial fall off the first step wouldn’t give the toy … Read more

The silver stuff in an Etch A Sketch is the metal aluminum, ground so finely that it sticks to everything. This is true even if it manages to escape the insides of the Etch A Sketch. This powder inside the toy is peppered with little plastic beads that keep it from clumping. The window of … Read more

The Star Trek television show was created by a man named Gene Roddenberry. In tribute to the man and his promotion of far-ranging space travel, some Trek-loving scientists have coined the term “Roddenberry” to mean the distance traveled at the speed of light during a “traveler year.” A traveler year is an Earth year as … Read more

We’ve all heard the story of the penny falling from the top of the Empire State Building and slicing its way through a parked car (or a pedestrian) below. It never happened, no matter what Jimmy Doofus in the fifth grade may have told you. Have you ever dropped a coin into a wishing well … Read more

Don’t try it. The ball’s extra weight and shape would do some real damage. Not that it would necessarily kill someone below, but getting hit by a falling baseball sure wouldn’t do them any good. There is, in fact, some data to back this up. In 1938, for a publicity stunt, some Cleveland Indians caught … Read more

According to scientists who have tested such things, here are the approximate terminal speeds for various common objects. As you can see, variables include weight and wind resistance. Raindrop: 15-20 mph Ping-Pong ball: 20 mph Golf ball: 90 mph Baseball: 95 mph Person spread-eagled: 125 mph Person balled up: 200 mph 30-caliber bullet: 200 mph … Read more

There’s controversy about the effects shaving has on swimmers. A few studies using a small number of swimmers have shown some improvement in performance after shaving. So that may be the answer. Skeptics, though, say the studies are flawed. Since most swimmers believe that shaving will help them go faster, they say it’s not surprising … Read more

It was golfers themselves who discovered that golf balls with nicks, dents, and scrapes flew farther than the round, smooth balls that were originally used in the modern game of golf. The effects were so dramatic that they began aging their new balls as quickly as possible by pounding and scraping them. Eventually, the manufacturers … Read more

“You never hear the one that hits you” was the fatalistic saying on the front trenches of many wars (not to mention the song of the same name by the rock group Stiff Little Fingers). Well, it turns out that the soldiers and the punk rockers had their physics down pat—, a bullet travels faster … Read more

What you’re hearing is part of the constant ambient sound that we don’t often register because it always surrounds us. The shell reflects and focuses higher frequencies back to our ears. The reason is that high-pitched sounds have short wavelengths, so they tend to bounce when they hit a hard surface. The longer wavelengths of … Read more

Oh, no, you don’t. This is one of those pointlessly endless questions with an answer that depends on how you define sound. If you define sound as “vibrations within a certain frequency,” then the answer is yes. If you define it as “something perceived by an ear,” then the answer is no. So to answer … Read more

After New Jersey Monthly journalist Steven Levy asked this question back in the mid-1970s, he tracked Einstein’s brain down to a shelf in the study of Dr. Thomas Harvey, —the doctor in Wichita, Kansas, who performed Einstein’s autopsy in 1955. The brain was separated into lobes and kept in two mason jars inside a cardboard … Read more

No, brain size doesn’t seem to matter that much. During early tests on Albert Einstein’s brain, for example, scientists found no significant difference between the size of his brain and those of people with normal intelligence. That said, there does seem to be evidence that genius brains may be different from average people’s brains. Although … Read more

Well, let us answer your question as you asked it and then answer what we think you’re really asking. Spontaneous combustion happens when heat-generating chemical reactions occur in an enclosed place. Usually heat from oily rags or mouldering vegetation escapes into the surrounding atmosphere, but if it’s stored in a place with poor ventilation, the … Read more

Ah, yes, that mysterious phenomenon that people like to scare themselves with around campfires and on supernatural Web sites. The stories have been around for centuries in legend, temperance tracts, and fiction. In Jacob Faithful (1834), novelist Frederick Marryat wrote about a character’s disreputable mother who “perished in that very peculiar and dreadful manner, which … Read more

In theory, water that has been boiled and cooled will freeze faster than plain cold tap water. Boiling removes the air bubbles that tend to slow down the freezing process, and it also reduces the amount of liquid. However, in your kitchen or ours, the time difference is so minuscule, it wouldn’t be noticeable. So … Read more

Russian scientist Dmitri Ivanovich Mendeleyev invented the periodic table in 1869. In gratitude, scientists named element 101 after him. mendelevium.

The invention of the thermoscope, a thermometer like device used to measure body temperature, is usually credited to the physician Santorio Santorio in 1612. Many argue that knowledgeable men of the day, including Galileo, collectively invented the device. However, Santorio was the first to actually add a number system to gauge changes in temperature.

Swede Anders Celsius invented the metric model or Celsius scale for temperature in 1742. But his version paradoxically had water boiling at 0 °C and freezing at 100 °C. Another Swede by the name of Carolus Linnaeus (who incidentally was also the guy who came up with the genus/species method of naming plants and animals) … Read more

Noble, in this case, has nothing to do with royalty. “Noble” metals stands for metals like gold, silver, platinum, and mercury that are resistant to reactions with other things. They don’t oxidize or rust quickly like base metals do. Base metals include copper, aluminum, lead, tin, nickel, and zinc.

Elements 57 through 71 plus the elements scandium (21), yttrium (39), and thorium (90) are all called rare earth elements. When many of these elements were discovered, the process of extracting them was difficult and costly. Scientists also believed they weren’t largely available in Earth’s crust. This is how they came to be called “rare.” … Read more

A palindrome, of course, is a word, phrase, or number sequence that can be read the same way forward and backward. An example would be the number 1234321 or the phrase “Egad, a base tone denotes a bad age.” Based on that, then, there are no palindromes in the names of the elements. Of course, … Read more

The undigested roughage, —grasses, hay, and other vegetation —is what burns and makes animal dung flammable. Most people who use dried dung cakes for fuel add more dried hay to the fire to keep it burning longer. Burning manure produces a lot of smoke, though, putting those in the home at risk for lung problems. … Read more

Just because something’s invisible doesn’t mean it’s weightless. So, no, air is not weightless. As a matter of fact, all gases have mass, and therefore they have weight. Air, a combination of gases, is fairly heavy. Good thing, too, —the weight of the air around us and the force it exerts on our bodies pushes … Read more

Helium is the second lightest gas in the universe. Hydrogen’s the lightest. Both gases have mass and therefore weight. It just so happens that they weigh less than air. Because of that, the heavier air sinks below them, pushing them upward— much in the same way that water flows below Styrofoam and pushes it toward … Read more

Quark is a nonsense word, coined by the writer James Joyce in Finnegan Wake. In the book, it may have referred to a cheer or the call of a gull, but these things are never completely clear when referencing the writings of the impossibly inscrutable Irish writer. In science, of course, a quark is nearly … Read more

Embark on a numerical journey as we ponder the colossal task of counting to a billion. Unveil the magnitude and intricacies of this remarkable numerical feat. Key Takeaways: Explore the theoretical duration of counting to a billion at various rates. Understand the incomprehensible scale of a billion in the context of time. Gain insights into … Read more

In our number system, nothing exists beyond infinity. Infinity doesn’t really exist. It is simply a concept, not a number or a thing in itself. If there’s anything “beyond” infinity as we understand it, it’s part of infinity. So, the answer is that if there’s anything beyond infinity, it’s just more infinity. Make sense?

There are several mnemonic ways to memorize pi. Most involve remembering a sentence or rhyme and counting the letters within each word. For example, count the letters of each word of the following phrase: “May I have a large container of coffee? Thank you.” “May” has three letters, “I” has one, “have” has four letters, … Read more

If the sun is too high in the sky, you won’t see a rainbow. The only time you can see a rainbow is either in the early morning or in the late afternoon. There’s a reason for this. For you to see a rainbow, the sun has to be in back of you and shining … Read more

From top to bottom, the colors in a rainbow are: red, orange, yellow, green, blue, and violet. Except in the case of double rainbows, which occur when light reflects off another set of raindrops and forms an outer rainbow that’s a pale imitation of the original. The color sequence in the reflected rainbow is reversed … Read more

If it’s average snow, not too wet, not too dry, you’d need about a tenth of an inch of water to make an inch of snow. The general rule is that one inch of water produces ten inches of average snow. But that’s the average. An inch of water would make about fifteen inches of … Read more

Hope for a small avalanche instead of a big one and wish for luck. A bona fide large avalanche can exert so much pressure that it snaps trees, rocks, and bones in its path, carrying enough snow to bury twenty football fields in ten feet of it. Large or small, you’d think an avalanche would … Read more

Officially, the hottest place in the world is Death Valley, California. On July 10, 1913, temperatures reached 134 °F (56.7 °C). Four years later, during the summer of 1917, Death Valley broke another record—the highest average temperature—by maintaining temperatures of over 120 °F (48 °C) for forty-three consecutive days. These are the official world records … Read more

Oymyakon, Russia, has a substantial, ongoing population of 4,000, and its temperatures have fallen as low as —72 °F ( —58 °C). People have visited spots even colder, though. In Vostok, Antarctica, people were present when temperatures got down to —89 °F ( —67 °C). But no one has set up residence there yet. Too … Read more

Surprisingly, no. Australia is not the driest continent on Earth. While much of Australia is very dry, the driest continent is a desert you might not even think of as a desert. It’s Antarctica. Deserts, you may remember, are not necessarily a place of great heat, but are instead characterized by a lack of rainfall. … Read more

Although locations along the equator are hot throughout the year, they do still have seasons. Usually two: a wet season and a dry season. The equator does not have regular seasons that North America gets as it receives a uniform amount of Sun throughout the year.

The windchill index is an interesting thing, an attempt to take a scientific certainty—, temperature and wind speed—, and quantify its effect on the perceptions of humans. In other words, it calculates perceived temperature. Scientists working in Antarctica developed the first formula to determine when the wind will turn a frigid temperature into a deadly … Read more

The traditional “dog days” of summer fall between July 3 and August 11, noted for their extreme heat and humidity. During this time of year, the star Sirius is at its brightest and can be seen rising alongside the sun. The phrase actually dates back to the Egyptians. They believed that the star gave off … Read more

Is the phrase “Indian summer” meant to be derogatory? Maybe, or maybe not. The phrase, of course, refers to a time in late fall when the weather turns unseasonably warm and mild. For many years, it was believed that the name came from the idea that Native Americans can’t be trusted, that “Indian summer” was … Read more

Although it sounds like a lot, and certainly seems like a lot if you’re the one doing the climbing, even Mount Everest is only 5.5 miles high. Considering that the sun is 93 million miles away from Earth, a measly 5.5 isn’t going to largely effect the amount and intensity of the sunlight you’re receiving. … Read more

Actually, winters are not getting colder. It only feels like it sometimes. Over the last many years, the world has slowly gotten hotter. This difference in temperature is minuscule—a fraction of a degree— which means that to most of us, things seem normal. However, it’s a potentially ominous indicator of global warming. It doesn’t take … Read more

Over the last sixty years, the average accuracy rate for groundhogs on Groundhog Day has only been about 28 percent. Punxsutawney Phil’s got a slightly more impressive record—he predicts correctly about 39 percent of the time. Maybe they’re using the wrong animal for the job. The original “groundhog” wasn’t a groundhog at all, but a … Read more

How accurate a read are you looking for? A cat can be used to give a very, very general idea of temperature. The colder the temperature, the more a cat curls around itself to sleep. If your cat’s lollin’ around, stretched out on her side or back, you can bet it’s warm. If said cat … Read more

Well, first of all, don’t stick a cricket under your tongue to tell the temperature. That won’t give you the information you seek, and nearly always damages the insect. First, some background: Cricket metabolism slows at a consistent rate when they get cold and speeds up when they get hot. This is true of not … Read more

There are two really good reasons. The first is temperature. A hurricane is created and fed with the hot air that rises off warm water. Conversely, cold water’s cooler air tends to sap the energy from a hurricane, pretty quickly killing it dead (the waters along our eastern coast have just returned from a tropical … Read more

There isn’t much difference between a typhoon and a hurricane, beyond their names and locations, they’re both tropical cyclones. Typhoons are hurricanes that occur in the western part of the Pacific Ocean or over the Indian Ocean. Hurricanes always take place on the Atlantic Ocean or the Caribbean Sea. Hurricanes get their name from the … Read more

Wind shear is a fancy name for turbulence— that windy stuff that makes airborne airplanes bounce a little. Wind can sometimes change directions suddenly, either vertically or horizontally, creating eddies and swirls and bumping into other wind currents headed in the opposite direction. Needless to say, if you’re floating on a cushion of air, this … Read more

Off screen, sensors like that don’t exist, although the idea has been experimented with by the National Severe Storms Laboratory, a government group that tracks and researches (you guessed it) severe storms. Here’s what the NSSL’s Web site FAQ says regarding the movie devices: The movie TWISTER was based upon work NSSL did in the … Read more

We’ve never actually tried using a television as a tornado warning device, so we can’t completely vouch for it. And of course, it’s best to make sure you’re in a safe place before trying it, we’d hate for you to be standing in front of your home entertainment center upstairs instead of huddled in your … Read more

Out of the twenty possible answers inside a Magic 8-Ball, ten of them are positive, five are negative, and five are noncommittal, suggesting you ask again later. That means you have a 1 in 2 chance of getting a positive answer, and only a 1 in 4 chance of getting a negative one, with another … Read more

Although Mattel, the toy company that now owns and distributes the toy, calls this patented contraption the “20-sided answer cube,” there is a more mathematically accurate name for the piece. All twenty-sided polyhedrons are called icosahedrons.

Have you ever wondered what stores do with beef that’s past its freshness date? It’s sold off to various manufacturers who render the fat (called tallow) and put it into all kinds of products, from hair conditioner to—you guessed it—crayons. The fat is often called “free fatty acid” or “stearic acid” on labels. That obviously … Read more

Definitely. Almost without fail, black’s the first crayon to go. This makes sense; folks of all ages tend to use black as an outline and background color for furniture, lettering, buildings, etc. Less predictably, red is usually the second one to go.

The master cut of a vinyl record was usually made from a layer of lacquer on top of a flat aluminum plate. A machine with a piece that looks a lot like a record-player stylus and needle was fed sound vibrations. In turn, this apparatus cut grooves with dips and bumps that correlated to the … Read more

In a world where computers and chips can create everything from dancing monsters to singing fish, it’s nice to know there are still some tried-and-true toys that are based on technology created over a century ago. The See ‘n Say basically uses the same technology that a record player does. There’s a disk inside the … Read more

First, a quick rundown of the anatomy of a yo-yo: two disks of equal size are placed together and connected with a little part in the middle called an axle. A string is affixed to the yo-yo, either by tying a loop around the axle or by attaching the end of the string directly to … Read more

On April 12, 1985, NASA decided to test just that. It sent a yo-yo into space with the astronauts aboard the space shuttle Discovery. What they learned was that a yo-yo would indeed work with little-to-no gravity. With a gentle push, it glided down the string and back up again. Simply dropping the yo-yo, though, … Read more

Because the tops of flying discs and Frisbees are rounded, air goes over them faster and has less density, creating lift, as with airplane wings. Air gets trapped underneath the disc and pushes upward, slowing the fall rate. The thrust of the throw gets the lift process started, but the spin only adds stability and … Read more

As one boomerang physics Web site states it: “Magic makes it come back.” Or scientifically, it’s a combination of lift, spin, and something confusingly titled gyroscopic precession. Gyroscopic precession is the principle that states that if an object is spinning, and movement (the tilt) is exerted on the object, it will move at right angles … Read more

Have you ever noticed how fast paint thinner evaporates at room temperature? It’s this little fact that makes the glass and plastic dunking birds work. Here’s how it works: The bulb that holds the colored liquid (methylene chloride) inside has a bubble of vapor on each end. At room temperature the liquid congregates mostly toward … Read more

Anything that’s lighter than air will float. A liter of air at sea level weighs about 1.25 grams; a liter of helium, though, is only .18 grams. Therefore the air sinks below the helium balloon, causing it to fly upward.

This seems like it should be an easy one to answer, but you’d be surprised at the explanations we’ve heard from people who should know better. Let’s go in order of what we consider least reasonable and work our way up: Because helium is less dense, sound travels faster through it, so the wavelengths are … Read more

The chemical process used in a glow stick is not that far from the chemical process that occurs inside a lightning bug. When you open the glow stick package, you find a stick with yellow liquid inside (generally, a chemical called luciferin). Inside the yellow liquid is a glass tube that contains a chemical enzyme … Read more