Science

Recent studies show that birds like Robins find worms in the ground visually, not by hearing or smell. When robins run along the lawn, cocking their heads, it looks like listening, but actually it is just looking. What the robin usually sees is the castings or pellets of mud at the entrance to the worm … Read more

Animals’ sensitivity to taste varies widely by species, but animals do have food preferences and many have taste buds. Animals also seek out food based on consistency, color and smell. Certain snakes that have poor eyesight have powerful receptors for the heat of their prey and make their choices based on that, and some animals … Read more

For most animals the idea of an expected life span is meaningless, since so many die shortly after birth and so few die of old age, except in captivity. However, reliable longevity records for individual animals have been kept. The animal with the longest recorded life span is the Marion’s tortoise of the Seychelles Islands … Read more

In some cases, different species of animals can understand each other. In research on the complex signals gulls send to each other within the same species, scientists found that birds in mixed flocks can respond to each other’s alarm calls, and that this could be a matter of learned behavior or an inborn instinct. It … Read more

Baby teeth are more scientifically called deciduous teeth, because they are shed like leaves. They are also called milk teeth, which is a clue to the answer. Mammals, with a few exceptions, have two sets of teeth. The key to mammalian success is specialized teeth for many different foods, and two sets, often with different … Read more

Yes, some animals do snore, according to anecdotal reports and personal observations. Just a few snorers that zookeepers and pet owners have observed are dogs, gorillas and bears. The mechanism of snoring in these mammals probably resembles what happens in people. In human beings, snoring is noisy breathing through the open mouth produced by vibration … Read more

Luckily for deep-diving whales, they have an entirely different system from that of humans for handling the air they breathe before diving and their oxygen needs while diving. When pressure is released on gases dissolved in the blood, the bends result. Whales are taking in air breathed at the surface and carrying it to the … Read more

Squirrels do indeed have a homing instinct. It is not well understood by science, but they will often return several miles. For example, an informal experiment was conducted at the Brooklyn Center for the Urban Environment in Prospect Park, which conducts extensive environmental education programs for school children and adults. Some years ago, a classroom … Read more

Dinosaurs probably did sleep, though it’s all speculation, because scientists don’t know enough about their physiology. The speculations are based on their structures and diets and on the habits of the presumably most similar living species, like crocodiles and birds, which do sleep. Carnivorous dinosaurs like Tyrannosaurus rex and Deinonychus would probably have slept a … Read more

Some marine mammals sleep out of the water, and some may not sleep at all. The furred or hairy aquatic mammals in the pinniped suborder, seals, etc. have a variety of interesting adaptations that permit them to spend a comparatively long time underwater, sometimes at considerable depths. However, they rise frequently to breathe and emerge … Read more

Relax and enjoy the bat’s company might be the best advice, if a bat ever flies into your house or apartment. A one-ounce brown bat, the kind most likely to show up in a North American house, is capable of eating five hundred mosquito-sized insects an hour all night, but is virtually incapable of doing … Read more

Sharks can definitely smell blood from quite a distance. Sharks have an extremely sensitive sense of smell for food in the water. A few molecules can be enough to draw a shark. A shark has nostrils, called nares, connected to olfactory bulbs that go back to the brain. Just by studying the brain, scientists concluded … Read more

Fish do have blood, and it is red. Other cold-blooded animals, like amphibians and reptiles, also have red blood. Fish have a circulatory system with blood and a heart as the pump just like that of humans, and just like that of humans, fish blood is red because it contains hemoglobin, the iron compound that … Read more

All fish have internal pressures that are equal to the pressures outside their bodies at their normal depths. This is true of both tissues and the gas-filled bladders in the abdominal cavity that many fish have. They would only be in trouble if they changed depth greatly. If they come up a great deal, they … Read more

There are nearly three hundred species in the squirrel family, and some of them, called tree squirrels, are expert tree nest builders. Some other species dig burrows and build nests there. Tree squirrels belong to the genus Sciurus. Their nests are called dreys. The common gray squirrel, Sciurus carolinensis, is a tree squirrel. Its natural … Read more

Marine mammals depend primarily on the water content of the food they eat, rather than on drinking sea water. Whales, for example, eat mostly shrimp-like krill and fish. A high percentage of the body tissue of fish is water. Toothed whales eat larger fish or squid, while the baleen whales, which are larger, take big … Read more

The cause of death when a Cormorant swallows its prey alive is, in all probability, suffocation. If not, the acid in the stomach compartments in the cormorant would interfere with oxygen transport in the gills. Pythons, boas and other constrictors kill their prey before they feed on it, by constricting and suffocating it before they … Read more

A few species of slugs are pests of agriculture and can destroy foliage faster than plants can grow. Most garden slugs, however, eat dead leaves, fungus, and decaying plant material. Some slugs are predators and eat earthworms, snails, and even other slugs. It may surprise someone whose vegetable garden has been munched by voracious shell-impaired … Read more

The true dolphin is a mammal, any one of about thirty-three species of cetacean mammals in the family Delphinidae, characterized by a pronounced beak-shaped mouth. The dolphin on restaurant menus, Coryphaena hippurus, is a fish with gills, iridescent colors and firm flesh. It is called mahi-mahi in Hawaii and dorado in South America. The dolphin … Read more

Shaving cream is basically made of soap and water. It is put into the can along with compressed butane gas. Without the gas, all you have is soapy liquid. When the valve is pressed, some of the gas mixes with the soap and water, escapes and expands to make foam. The filling process is just … Read more

A fabric softener sheet put in the dryer works much the way a liquid fabric softener does. But it includes agents that disperse very small amounts of softening and antistatic components throughout the warm air that permeates the damp fabrics. Fabric softening agents are surfactants, chemicals that reduce the tension at the surface where two … Read more

In an adult giraffe, the systolic blood pressure, the pressure when the heart contracts to pump blood through the body, is about 200 millimeters of mercury at the level of the heart, about twice that of an adult human being. During exercise, the blood pressure at the level of the giraffe’s feet might be double … Read more

Many of the specific techniques machines use to detect counterfeit money are closely guarded secrets, since once counterfeiters know how the machines work, they try to foil them. But two common means of identifying paper money are magnetic sensing and optical sensing. Inks used to print notes have certain magnetic properties, which can be sensed … Read more

French dye-works owner Jean Baptiste Jolly discovered dry cleaning with petroleum-based solvents in the mid-19th century. Dry cleaning is dry in the sense that the solvents used have no water. Although they are liquid, they have the ability to remove soil without affecting fabric as water would. They also evaporate quickly and leave dry clothes … Read more

At room temperature and pressure, carbon dioxide, or CO2, is a common gas, about 0.05 percent of the air at sea level by weight. It is also a product of combustion and the respiration of all animals. When chilled below minus 109 degrees Fahrenheit, it becomes a solid, called dry ice. Dry ice was first … Read more

Clothes shrink because of the chemical and physical properties of fibers from natural sources, especially cotton, wool and linen. The individual fibers in yarns are made of long polymer chains, or strands of giant molecules. In their natural state, the chains are scrolled up or crinkled. In preparing them for spinning and weaving, the first … Read more

The first time-release medication was probably just a sugarcoated pill. The coating did not dissolve and release the bitter medicine until it was safely past the mouth. Many time-release medications, like Contac, introduced in 1961, are based on that fairly simple idea: small amounts of the medication are coated with varying thicknesses of soluble material. … Read more

There is no data to support the belief that freezing nylon hose makes them more durable. Nylon is a fiber made from petroleum derivatives. Properties such as strength and resistance to fatigue, or stress from flexing, and abrasion do not differ depending on temperature, particularly by the time nylon is in a finished article. By … Read more

The central processing unit, the microprocessor that actually performs the calculations, is what takes the most power when the calculator is running. The more calculations the machine is asked to perform, the more power it would draw. Just being turned on would take only enough of the calculator’s battery power to light up the display. … Read more

Aluminum foil is produced by rolling sheet ingots cast from molten aluminum, then re-rolling on sheet rolling mills to the desired thickness. Beta radiation is passed through the foil to a sensor the other side to help maintain a constant thickness in aluminum foil production. The shiny and dull surfaces result from the final rolling … Read more

The non-soluble gum base of chewing gum is not digested, but neither are parts of many foods, like popcorn or lettuce, experts in the food industry say. Gum typically contains five ingredients: sugar, corn syrup, softeners, flavors and a non-soluble gum base. The first four ingredients are soluble and are extracted as the gum is … Read more

The dial tone on a telephone isn’t really a pure A, but a composite of two frequencies: 350 hertz, or cycles per second, and 440 hertz. Most symphony orchestras tune to an A of about 440 hertz. The tone was apparently not intentionally selected to make life simpler for musicians with no tuning fork, but … Read more

Alcohol is the safest solvent for drugs that do not mix well with water, as pharmacists have known since ancient times. Safe, that is, for the general population. For an alcoholic or anyone else who does not want to ingest spirits, a pharmacist will recommend a tablet or lozenge, or for a severe cough, a … Read more

Hot water is more effective for cleaning dirty dishes for two reasons. First, hot water melts fats and softens other food particles, making it easier for detergent to penetrate them. The active ingredients in dishwashing detergent, known as surfactants, are chemicals that bind fat and water together so they can be removed from the dish. … Read more

The scale of relative hardness, developed by Stanley F. Rockwell around 1920, runs from C20 to C80. Each point on the Rockwell scale represents 80 millionths of an inch of depth when the steel is tested with a sharp point and a standardized weight. The higher the number, however, the harder the steel. In general, … Read more

A rearview mirror with a night position is actually two reflective surfaces. One is a shiny mirror that is about 90 percent reflective. Over it is a wedge of glass that is only about 4 percent reflective. The wedge is very thin and angled only a few degrees. In the daytime, the mirror is angled … Read more

Using a battery-operated device continuously for four hours would run down a battery faster than using it for an hour on, then an hour off, for four cycles. The reason is that batteries have a tendency to recover a little bit if not used for a time. A battery’s current comes from electrons that are … Read more

Newer magnets are made of materials that are far less likely to lose their magnetism over time than the old horseshoe magnets. Magnets are composed of many little magnetic regions called domains. The magnetic field of the whole magnet runs opposite to the direction of the domains that cause the field. That tends to make … Read more

The necklaces and other temporary chemical lights work by imitating the chemical reaction called bioluminescence that allows fireflies to light up. The reaction in the plastic tube is oxidation, as in burning, but the chemicals involved, called luciferins, produce more light than heat. When the proper chemical is mixed with diluted hydrogen peroxide from a … Read more

The simplest way, and one that is still in use with the aid of satellites, is just an elaboration of how scouts are taught to measure the height of trees, by constructing a triangle with some known values and then filling in the blanks. In the surveying method called triangulation, a baseline of a known … Read more

Sea level, actually mean sea level, is calculated as the average height of the sea surface taking into account all stages of ocean tides. It is measured at various locations by a network of tide gauges over a nineteen-year period. Scientists have long recognized the inaccuracy of these tide measurements, and satellites are offering more … Read more

A hollow tube called a pitot tube is mounted on the surface of the nose of an aircraft. As they board, passengers may be able to see this tube on the nose toward the bottom of the plane. The tube is parallel to the air that comes over the plane, and measures what is called … Read more

For many years, the international standard for defining all units of length was the meter as defined by the distance between two scratches on a platinum-iridium bar. The bar is stored in a vault at the International Bureau of Weights and Measures at Sevres, near Paris. In 1960, the basis of the standard was changed … Read more

Not a great deal is known about Roman mathematics because they were not terribly interested in it. Doing arithmetic probably played a much smaller role in the everyday lives of Romans than it does in ours. The Romans had signs for 1, 10 and 100, etc., but they did not have a place value system, … Read more

Objects weigh less the further they go below the earth’s surface. If you assume that the earth is a perfect sphere with a uniform mass throughout, and you went below the surface of the sphere, only the mass within your radius would contribute to your effective weight. The radius of the earth is 6,371 kilometers. … Read more

Theoretically, it would go all the way through and then back, oscillating back and forth forever. The brick would be exactly like a mass on a spring pulling it toward the center of the earth. Momentum keeps it going through the center, but after that the spring is slowing it down. The object goes all … Read more

Daniel Gabriel Fahrenheit, who devised the scale, wanted natural reference points, but he did not choose wisely. Fahrenheit, an instrument maker born in Danzig in 1686, developed three different temperature scales as his knowledge of natural phenomena increased. He chose points like the freezing temperature of water and the underarm temperature of a healthy adult … Read more

Standing near and touching the radio probably represent two different phenomena. In addition to traveling from one point to another, radio waves are being reflected and absorbed by objects in a room, and the pattern of reflection can cause interference as the spurious signal interferes with the original signal. Standing in the path of the … Read more

Daytime visibility is defined as the greatest distance at which it is possible to see and identify, with the naked eye, a prominent dark object against the sky at the horizon. Daytime visibility reports are estimates based on local landmarks and conditions. Nighttime visibility is the greatest distance at which it is possible to see … Read more

Yes, you can take your garden sundial to the same latitude in the southern hemisphere, but the numerals would have to be reversed in a mirror-image way. That is, for example, the displaced sundial would show 1 P.M. when it was 11 A.M. While the sun’s apparent path across the sky moves from east to … Read more

What we think of as weight is the gravitational pull of the earth itself on a person or object. Therefore, asking the earth’s weight is essentially meaningless, because it has weight only in relation to another object. However, the mass of the earth, the quantity of matter in it, can be estimated by calculating its … Read more

It is widely believed that planet earth is gaining mass. A large number of small meteorites strike the earth every year, while the amount of material thrown out into space is comparatively negligible. Most of what is launched returns to earth as man-made meteorites. Everything that is sent into orbit remains in the range of … Read more

There is no maximum temperature, because there is no limit to the amount of energy you can put into anything. Absolute zero, minus 273.15 degrees Centigrade, minus 459.67 on the Fahrenheit scale, is theoretically the temperature at which all molecular activity ceases. It represents an absence of energy. There is the concept of a lowest … Read more

The treeline or timberline, the line on mountains and in polar regions beyond which trees will not grow, is mostly determined by temperature. Trees need a long enough and warm enough summer to ripen seeds, produce new wood and form buds. However, temperature is not the only factor, and the altitude above sea level is … Read more

Not everyone does, but those who do, do so because of a phenomenon called binocular rivalry. If you look through a sight with the left eye, what you see is not identical with what you see with the right, and the two images compete, rather than blending, as they normally do when you look at … Read more

Degree days are used as an approximate measure of energy demand to let utilities and householders keep track of what energy use for heating or cooling ought to be from day to day or year to year. To calculate degree days for a given day, add the high and low temperatures, divide by two and … Read more

The term humiture was coined in 1937 by O. F. Hevener, a meteorologist, to refer to the discomfort felt in the upper temperature ranges when the humidity rises. The higher the humidity, the warmer it feels to the human body, because it cannot evaporate sweat as easily. Many indexes have been devised to quantify the … Read more

The curved surface of a clear measuring cup, either glass or plastic, acts as a simple convex lens, very much like the ones in eyeglasses. The light rays passing through the cup are bent in such a way as to magnify the image from inside the cup. The result is that looking down into the … Read more

The measurement of rainfall is fairly straightforward, but snowfall presents problems that make measurements somewhat arbitrary. For rain, the meteorology department at Pennsylvania State uses a simple cylindrical tube to catch it. The amount that falls in a given period is poured into a smaller cylindrical tube that is carefully gradated and measured with something … Read more

The transporter in Star Trek will probably never be invented, scientists suspect. In a sense, the human genome project would be the first step in such a project, because you would need the whole genetic blueprint of a person, present in each cell, to copy the cells. But even if you had all that information, … Read more

In effect, a person who died in the icy vacuum of space would be freeze-dried, space experts theorize. The water in the body would freeze and eventually dissipate into space. Ice can evaporate without going through the liquid phase. Because there is no oxygen, there would be no decomposition, and there is little evidence that … Read more

There are two federal agencies that offer very accurate time signals by telephone, and one of them offers shortwave radio broadcasts of the same information. Dialing the United States Naval Observatory Master Clock at (202) 762-1401 puts you in touch with a time signal in hours, minutes and seconds, on a twenty-four-hour clock in Eastern … Read more

The space suits worn by United States astronauts are made of several layers of super strong fibers and other materials that are tough enough not to rupture in the vacuum of space. The materials in the nine or ten protective layers include: 1. Orthofabric, which is Teflon with Kevlar ripstop protection. 2. A layer of … Read more

Since we can’t actually weigh astronauts in weightlessness, body mass measurements are used to determine any change in weight. Weight, in this case, is what the astronaut would weigh under the influence of earth gravity. Such measurements are made with a spring-like device and a highly accurate timer. By measuring the time, or periodicity, between … Read more

On space flights in the past, the components of breathable air, oxygen and nitrogen, were brought up in canisters. However, when the space station built, plans were announced to have it carry equipment to recover oxygen indirectly from the carbon dioxide crew members exhale. astronauts NASA’s Johnson Space Center tested means to recycle air and … Read more

There are more grains of sand on earth than stars in the universe. The recently published data from Hubble Space Telescope images help confirm scientists long-held suspicion that the universe has many galaxies invisible to ground-based telescopes, so an increase from ten billion galaxies to fifty billion was not unexpected. Some estimates have gone even … Read more

Latitude and longitude are also used on the moon by the astrogeology department of the United States Geological Survey in Flagstaff, Arizona, which maps extraterrestrial bodies. Like the earth, the moon has an axis of rotation and an equator, so latitude is indicated in degrees of latitude north or south of that equator, just as … Read more

According to NASA, astronauts do not use compasses in space, but near-earth orbit would not change the behavior of the magnetic needle significantly. If the compass were in the cockpit of an orbiter, it would probably behave much as it does on earth. The needle would follow the lines of the planet’s doughnut-shaped magnetic field … Read more

Many researchers think the phenomenon of the moon showing the same face, called gravitational phase locking, occurs because of the uneven distribution of matter in the bodies involved. Normally, when two bodies join in holy matrimony and decide to go around together forever, their spins would stay what they were beforehand. But because they may … Read more

Astronomical temperatures are usually estimated from spectroscopic measurements. The spectroscope was invented in 1859 by two German scientists, Robert Wilhelm Bunsen of Bunsen burner fame and Gustav Robert Kirchoff. It was first used to analyze the elements in a substance heated to incandescence, each element gave off characteristic wavelengths of visible light. Bunsen used the … Read more

What makes that question interesting is that it presumes there is some reason you couldn’t. The moon is just as much out in daytime as it is at night. In the daytime, the sun is so much brighter than everything else that the moon may not be noticeable even when it is visible. At night, … Read more

Yes, sometimes, but it is not a simple slowing because of friction with a stationary air mass. The effect of the atmosphere on the rotation came about because of the way the sun’s heat and the absence of it alternate to stir up the atmosphere. The resulting wind patterns sometimes speed up the earth and … Read more

Stars and to a lesser extent planets twinkle simply because we are seeing them through the many layers of the atmosphere of the earth. These layers of different densities move around, bending or scattering sortie of the light. The upshot is that all the rays of light that could reach your eyes from a star … Read more

Scientists believe the earth’s tilt results from the impact of another celestial body during the later stages of the formation of the solar system. The planets are believed to have formed when smaller bodies were drawn together by gravity, hitting each other at high speeds. One of the later, larger impacts may not have been … Read more

Planets and moons are not perfectly round, of course. They only seem spherical, or almost spherical. Earth, for example, is flattened at the poles, and Jupiter and Saturn, because their extremely dense atmospheres are all we can see, appear even flatter at the poles. The reason that stars, planets and so forth are even almost … Read more

It is a common belief that the direction of rotation of a bathtub or toilet vortex is determined by the hemisphere it occurs on. Theoretically, water draining from a bathtub is affected by the Coriolis force, the inertial force caused by the earth’s rotation. It would have a tendency to go straight down. North or … Read more

There are two main theories on the origins of the earth’s water. Some believe the water was here from the start, some think it came later, from comets. Years ago, people tended to assume that the water concentrated at the earth’s surface was locked up inside and slowly emerged over the 4.5 billion years of … Read more

Yes, but you won’t see our summer stars, but their summer stars. You see another set of constellations, including many we never see, summer or winter. As you travel south, the constellations near Polaris, our north star, get lower and lower in the sky. The Dig Dipper would disappear by the time you get to … Read more

The zodiacal signs originate in Babylonian astronomy during Neo-Babylonian times around 7th century BC. The real sky that the zodiac corresponds to is simply those constellations through which the sun appears to move during the course of the year as seen from the earth. People living anywhere on the surface of the earth would pretty … Read more

No, and in fact there are submarine volcanoes, called guyots or seamounts. Their molten rock spreads on the ocean floor and is eventually cooled by sea water, creating what is called pillow lava. At depths below 6,600 feet high pressure prevents the explosive formation of steam that results when water meets molten rock at higher … Read more

While scientists have calculated a mean sea level for the earth as a whole, it is only a mathematical average value taken from a series of observations around the world. In fact, there is no single “sea level,” and the large bodies of water in the world have different and constantly varying levels because of … Read more

We have all been taught that the tides are chiefly the result of the gravitational attraction of the moon on the waters of the earth’s oceans. But there are actually two rotational systems involved, and two bulges of water. First, the moon goes around the earth, or so it appears. Actually, both the earth and … Read more

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 … Read more

Ice floats because water molecules occupy more space in the solid state than in the liquid state, so that a given volume of ice is lighter than the same volume of water. The way molecules fit together in ice crystals is not as compact as in water. They don’t change size, it is just the … Read more

The big East Coast storm of December 1992 was called a northeaster when it came up from the south because the surface winds and the high-level winds of such a storm often go contrary to one another. The high-altitude winds moved the storm from south to north, but the surface winds spiraled from the northeast. … Read more

Rocks that erode on the continents contain salt, which is brought by the rivers to the ocean. In fact, fresh water rivers carry a certain amount of dissolved minerals. Most of it is common table salt, NaCI, or sodium chloride. Once the salt gets to the sea, it tends to stay there and accumulate. Sodium … Read more

Although archeologists tend to uncover things, that is not necessarily because ruins have sunk beneath the surface of the earth. Instead they are usually covered over with newer buildings or natural deposits of sand and debris. There are exceptions, for example, in Mexico City, the Aztecs built temples on a lake bed, where they did … Read more

Meteorologists joke about building trailer parks to attract tornadoes, and there is more than a grain of truth in the jest, because trailer parks tend to occupy the kind of terrain that allows tornadoes to develop. About 80 to 90 percent of the time, tornadoes are the offspring of a thunderstorm that is rotating, spinning … Read more