Science

Historians of science find the obvious explanation for the base-10 system at the fingertips of human beings, all ten of them. Not so coincidentally, the word digit comes from digital, the Latin word for finger or toe. Counting on the fingers (base 10) or the fingers and toes (base 20) is the apparent root of … Read more

The long pointed bottom of the typical amphora actually gave it an excellent shape for stacking against a ship’s hull, ensuring that the oil or wine within would be safe during transport. In the evolution of amphorae, they often began rounded and egg-shaped and shifted to pointed, because the long bottom of the brittle pottery … Read more

Not unless the victim that is, patient chanced to be suffering from a hypertension crisis or an abnormal buildup of iron in addition to whatever disease the doctor thought he was treating. For example, draining 10 to 12 ounces of blood, for a start, and up to 80 ounces in all, was routinely prescribed during … Read more

There is no scientific evidence that any person ever spontaneously combusted, and no scientifically known means by which it could happen. In a typical case where there has been a report of a body burning unusually, a simple or at least plausible explanation is available when the case is examined in detail. A statistically typical … Read more

Historians agree Greek fire existed, but debate its nature. Some credit Callinicus of Heliopolis with building fire-spouting ships that defended Constantinople from the Arabs in 673. Greek fire was described as a liquid that burned even on the sea surface, with smoke and whooshing sounds. Candidates for ingredients include petroleum, resin, and quicklime, plus an … Read more

The building does move, but the motion is a very slight bending, only about a quarter of an inch, in winds of more than 75 miles an hour. The illusion of a larger motion probably has to do with wind-whipped clouds; an observer on the ground can see a tall building appear to “fall” if … Read more

Historically speaking, New York City is less prone to thunderstorms than many areas of the country, but the island of Manhattan is not immune to lightning. For example, the Empire State Building is struck by lightning on average about two dozen times a year. The good news for Manhattanites is that modern high-rise buildings have … Read more

Just about any organic material will explode if it is fine enough, dry enough, in suspension in air, and confined. All it takes is the fuel, oxygen, and a spark. Sugar, coal dust, wood dust, walnut hulls, the ingredients of children’s modeling dough, and some medications have also been involved in recent dust explosions. Organic … Read more

They work somewhat the way an old-fashioned stereopticon viewer (holding two slightly different photos) works. Each eye focuses on a separate image, but the brain combines them into one image that gives the illusion of depth (the third dimension) in addition to width and height. It does this by matching up the similarities and adding … Read more

Several kinds of technology have been used for touch screens. If the screen responds without actually being touched, it probably uses a system that has tiny infrared light emitters and detectors along the edge of the screen. When a finger interrupts the grid of beams, a computer can tell its exact position. Some screens sensitive … Read more

The paper is oxidizing, one of several destructive processes that affect paper. Newsprint is high in lignin, one of the main structural components of wood. When lignin is in contact with oxygen, a highly reactive chemical, the reaction changes the way the fibers reflect light, discoloring the paper. Oxidation also produces more acid, a major … Read more

Antifogging agents are chemicals that force the tiny droplets of water that make up fog to merge into a transparent sheet. An agent is sprayed as liquid on the lens, and when it dries, it forms a clear film. Normally, water beads up, but with the film, the beads run together. The water is still … Read more

There are two reasons why cookware may heat up excessively in a microwave oven. The first is the same effect that occurs in cooking: friction. Microwaves are rapidly fluctuating electromagnetic fields, which push on electric charges and twist naturally polarized particles like water molecules back and forth. In liquid water, this twisting leads to molecular … Read more

The “steam” you see is what steam engine enthusiasts call wet steam, because it contains unevaporated water as a mist within the actual water vapor, which is a colorless, odorless gas. Dry steam does not contain any unevaporated water. Steam vapor forms at temperatures above the boiling point, normally 212 degrees Fahrenheit. Visible steam is … Read more

Conditions that are very like an allergy to winter are not only possible but common. Your friend’s problem could be an asthmatic reaction to exercising in the cold, or it could be an allergy to something she is exposed to in winter even more than in the traditional allergy season. It could even be that … Read more

Probably not, but more research is needed to know the degree of danger presented by the fumes emitted from diesel vehicles. Cars, trucks, and buses, especially diesel buses, emit large amounts of tiny particles that remain airborne for long periods. Because they linger, holding the breath until the bus passes is ineffective in keeping them … Read more

There are many theories about the high AIDS rates, especially in sub-Saharan Africa, and answers almost certainly lie in combined economic, sociological, political, and medical factors. For example, the rate of HIV infection in Botswana, the highest in the world at 35.8 percent of adults, has been linked to Botswana’s location and excellent road system, … Read more

Scientists don’t know for sure, but the most likely explanation is that rats probably would not survive an encounter with an infected carnivore, and so would not be around to transmit the disease to people. It is also possible that rats may lack a means of transmitting the virus within the species, because of mouth … Read more

Conservation biologists use population viability analysis (PVA), a relatively new method, to predict the viability of a species in a particular habitat. Computer modeling generates PYAs using life history data, genetic variability, and a population’s response to environmental conditions-especially disturbances-to predict viability of a species. A typical species becomes extinct within 10 million years of … Read more

Since it is usually impossible, and often impractical, to count all individuals in a population, researchers use a variety of sampling techniques to estimate population densities. One method is to count the individuals in a certain area. The larger the number and size of sample plots, the more accurate the estimates. Population densities may also … Read more