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 […]
Many insect species swarm, both the beneficent (like honeybees) and the irritating (like mosquitoes). In many cases, springtime swarms consist of groups of males all looking for suitable mates. Pheromone signals probably keep the group together. As insect mating, egg laying, and hatching tend to take place in synchronized waves, it is not surprising that […]
The key to a birdhouse is not a manufacturer’s custom design but a simple box of the proper size. If you put up nest boxes of the proper dimensions, you will typically get a wren or a chickadee; a flicker or a red-bellied woodpecker; a screech owl; and perhaps a titmouse, for a usual maximum […]
What Was the Ancient World and What Developments Marked the Transition From Prehistoric To Ancient History?
There is no exact date when the period known as the ancient world began. There are, however, two important developments that mark the transition of mankind’s history from prehistoric to ancient: farming and written language. Around 8000 B.C., the human lifestyle started to change as people learned to be farmers. Before this, most humans roamed […]
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, […]
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 […]
The brain’s activities do expend energy, and fuel is burned, but in very small amounts. In the sense of actually breaking down fatty tissue so that one might lose weight, thinking would play a very minor role. Extensive studies of brain function have been made and the varying levels of energy use at different levels […]
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 […]
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. […]
The smoke from dry ice isn’t smoke; it’s fog. Although dry ice is pure carbon dioxide, the fog itself is not carbon dioxide, as some people think. Carbon dioxide gas is invisible. The cloud of fog surrounding the dry ice is pure water. It has been condensed out of the air’s natural humidity by the […]
Scientists have estimated how much the sea level would rise, but the exact amount of land lost would require a very complicated worldwide coastal survey. Perhaps only the military knows. Melting the East Antarctic Ice Sheet would raise sea levels about 60 meters worldwide, or about 200 feet, while melting the West Antarctic Ice Sheet […]
How Do Penguins Prevent Their Feet From Freezing In the Winter and How Do Penguins Stay Warm In the Cold?
Penguins, like other birds that live in a cold climate, have adaptations to avoid losing too much heat in the winter and to preserve a central body temperature of about 40 °C. The feet pose particular problems since they cannot be covered with insulation in the form of feathers or blubber, yet have a big […]
Immunity is long-lasting because some of the many kinds of cells that make up the normal human immune system are naturally able to retain a “memory” of the defense efforts aroused by certain infections or vaccines. There are many kinds of immune cells, including T cells and different types of white cells. Their interaction with […]
Vidalias aren’t unique in their mildness. There are several brands of mild onions grown in other parts of the country, including the Maui, Walla Walla, Texas 1015, and OSO. Note that I have called them “mild,” not “sweet.” They don’t necessarily contain more sugar than other onions; they simply contain lesser amounts of both the […]
Why Does Stephen Hawking Believe There Is a Single Unified Theory That Explains Everything In the Universe?
Like Albert Einstein, Stephen Hawking hopes for “a complete, consistent, and unified theory of the physical interactions which would describe all possible observations”, a theory for everything. Sometimes there are contradictions in science’s greatest breakthroughs. For example, Newton’s theories explained gravity and motion, and Maxwell’s theories explained radiation, but the two could not agree on […]
The pat answer to the everyday puzzle of why things float invariably goes like this: “According to Archimedes’ principle, a body immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced. And that’s why things float.” Perfectly correct, of course, but just about as illuminating as a […]
Big waves can damage a coastal reef when they break, but 100 miles at sea, waves do not affect the sea floor. As a rough formula, if the wavelength, the distance between successive crests, is less than four times the depth of the ocean at that point, the waves do not affect the bottom. In […]
What Time Is It At the North Pole, Does the North Pole Have a Time Zone, and What Time Do You Want It To Be?
There are two answers to this question. The first is that the time for a person is the time determined by her or his circadian rhythm. Initially, this physiological time will be close to the time for the longitude where the individual lived before visiting the pole. Over a period of weeks at the pole, […]
Charles Darwin had formulated his theory of evolution by 1838. In 1858, he still had not written any papers or books on the theory. Darwin was very concerned about public reaction to a theory that disputed the biblical story of creation. He remembered clearly what had happened to Italian scientist Galileo under similar circumstances. He […]
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 […]
The gestures that birds make when they put dust on their feathers and then shake and preen it off look like the movements they make when bathing in water, but the purpose is not exactly the same. Birds take dust baths to rid themselves of all sorts of parasites that crawl in and between their […]
A molecule of any fat (a triglyceride) contains three fatty acid molecules attached to a glycerol (glycerin) base. The three fatty acids can be any combination of saturated, monounsaturated, or polyunsaturated. The health consequences of any given fat are purely those of the fatty acids (I’ll call them FA’s from here on) it contains. The […]
When Did Antoni van Leeuwenhoek Discover Bacteria With a Microscope and Where Do Beasties Come From?
In 1683, Antoni van Leeuwenhoek made his greatest discovery. He called them “beasties.” One day, he put a drop of stagnant rainwater under his microscope and saw “dozens of little animals, swimming and wriggling in that tiny drop of water, wretched beasties, a thousand times smaller than you can see with the naked eye.” Van […]
Not a diagnosis per se, but there is a name for the condition. It’s called an epigastric sensation.
Haven’t we become a bit of a paranoid society? Our drugstores and supermarkets cater to our fears (or do they encourage them?) by displaying dozens of antibacterial soaps, sprays, gels, lotions, hand washes, body washes, wipes, deodorants, and mouthwashes. Television commercials strike terror in our hearts by suggesting that there might be a germ or […]
The fog is exactly the same as any fog: a collection of tiny particles of liquid water that have been condensed out of the air by a cold temperature, but are too tiny to fall down like rain. They are kept suspended by being constantly bombarded by air molecules. They look white because they reflect […]
A pregnant woman can pass on some kinds of immunity to the baby, whether she has been immunized or not. These maternal antibodies are very powerful, and babies are protected for several months. That is why the measles vaccine is delayed until the age of nine to fifteen months. At earlier ages, the antibodies interfere […]
There are some rules of thumb for estimates for a limited area, but estimates for whole countries or the world are just guesstimates. Archaeologists tend to find and count all the formerly inhabited sites in a study area; make an educated guess about which ones were occupied at a certain period, usually based on pottery […]
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 […]
A spinning bullet flies farther and truer than it would without the spin. And if your favorite sport is football rather than shooting, just about everything I’m going to say about spinning bullets also goes for spiraling passes. The fact that a spinning bullet or football goes farther may sound strange, because you’d think that […]
No, Pluto and Neptune won’t collide. Their closest approach is not close at all about the distance between Uranus and the Sun. One reason they cannot pass any closer is that Neptune completes its orbit three times in the time that Pluto goes around twice. This exact relationship is called a resonance. Another such relationship, […]
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 […]
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 […]
Just take an old surfboard, punch lots of holes through it, and connect them to a water tank placed on top of the board. Water escaping through the holes will create the same effect that you can observe when spitting on a hot iron plate. The droplets dance on the plate for quite a long […]
Most people seem to think so that eating ice cream in hot weather cools you off. At the local Dairy Queen there is always a long line of people seeking cool after-dinner desserts in the summer, but starting the day after Labor Day, the place is virtually “desserted.” The answer to the question is in […]
It can be either very healthful or very noxious, or both. A study by scientists at the U.S. Department of Agriculture, done with money from the Peanut Institute, suggests that peanuts may contain enough resveratrol, the compound in red wine associated with a low rate of heart disease, to be helpful to human health. The […]