The beginnings of Michael Faraday’s ideas about magnetism started over 200 years before in a book titled Of Magnets by English scientist William Gilbert. It was published in 1600 and was probably the first great scientific work written in England. Gilbert was a remarkable scientist who was centuries ahead of his time in many fields. […]
Jell-O and similar desserts are about 87 percent sugar and 9 or 10 percent gelatin, plus flavoring and coloring. Kids love three things about the stuff: It is brightly colored, it is very sweet, and it jiggles. Mothers don’t mind, because gelatin is pure protein. The gelatin, which of course is the jiggler, really does […]
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 righton 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 eacha sun in a low […]
What Are the Four Humors of Hippocratic Medicine and How Were The Humors Related To the Four Elements?
Not all of Hippocrates’ ideas were accurate. Hippocrates believed that illness occurred when body fluids were out of balance. These fluids were called humors and included blood, phlegm, yellow bile, and black bile. The humors occurred when the four main elements of Greek thought: fire, air, earth, and water, mixed with dryness, dampness, heat, and […]
How Do Oceanographers Determine the Average Depth Of the Ocean When Waves and Tides Affect the Measurements?
The ocean floor is mapped using satellite measurements of gravity anomalies. The ocean floor is static, so the measurements can be averaged over a long period to give quite a high level of precision, though unfortunately not to the nearest inch. In any case, knowing the average depth of the ocean is not really important […]
It is a complex question, made even more complex by factors like the prior activity of each individual and how long each has been in the room. Assuming that both people have become acclimatized to the room and that neither is running a fever, there are two important factors. One is the percentage of body […]
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 […]
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 […]
Sheep can swim, but only in dire circumstances. The ability is basically instinctive, and a life-saving device. They don’t go swimming every day, but in case of flooding, or falling into a river, in essence they know how to swim. Sheep have never been known as big swimmers, and most of the habitat where they […]
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 […]
Fingernail growth averages out to about a tenth of a millimeter a day. Toenails are about a half to a third slower, and drugs or disease can change the growth rate. There are differences from finger to finger. The middle and fourth finger tend to grow a little faster than the fifth and the thumb. […]
It depends. The old phonograph records spun at a constant speed (for example, 33 or 45 revolutions per minute). That made it easy to make a turntable to handle them, but it meant that the music recorded near the outside of the record had better sound than the music recorded on the inner grooves. A […]
Two things makes chocolate dangerous to dogs. The first is the worst, a chemical called theobromine. The second is rather high levels of caffeine. A small amount of chocolate is unlikely to cause much harm, but in large amounts theobromine can be very dangerous. Eating an entire box of chocolates is more dangerous to a […]
How Do Bumblebees Fly With Such Tiny Wings and Why Does the Flight of a Bumblebee Defy the Laws of Physics?
The infamous case of the flightless bumblebee is a classic example of being careless with approximations. It stems from someone trying to apply a basic equation from aeronautics to the flight of the bee. The equation relates the thrust required for an object to fly to its mass and the surface area of its wings. […]
The arctic tern migrates the farthest in a year, by a long way. It migrates 22,000 miles each year, flying from the Arctic Circle to Antarctica and then, half a year later, flies back again. That’s quite the journey for a bird.
Well, what does “transparent” mean? It means that any light being reflected in our direction from an object outside a glass window, for example, can pass right through the glass unobstructed and come out the other side, where our eyes can deal with it. We therefore see the object through the window. That’s why people […]
Humidity is one of several atmospheric factors affecting the propagation of sound. Heavy, muggy air actually carries sound better. Bone-dry air greatly attenuates sound. But humidity is not as prominent a factor in affecting low-frequency sound as the bending of sound rays (or sound waves going in the same direction) by wind and the temperature […]
Yes, but it is not a good idea except under very special circumstances, because too high a concentration of oxygen or oxygen at too high a pressure can be toxic. For example, when a diver gets too much oxygen at high pressure, oxygen toxicity can cause lung damage and even convulsions. However, pure oxygen in […]
It’s a matter of how much oxygen is available to the burning fuel. Lots of oxygen makes blue flames, while a limited amount of oxygen makes yellow ones. Let’s look at the yellow flame first. A candle is really a very complex flame-producing machine. First, some of the wax must melt, then the liquid wax […]
Rigor mortis is gradual, usually noticeable about three to four hours after death, and the timing varies with several factors, including the person’s activity just before death and the temperature of the body’s surroundings. How long it takes the muscle stiffness to subside also varies, with rigidity usually reaching a peak after twelve hours and […]
Being stung by a nettle is painful because the sting contains an acid. Rubbing the sting with a dock leaf can relieve the pain because dock leaves contain an alkali that will neutralize the acid and therefore reduce the sting. Bees and ants also have acidic stings, so dock leaves should help, but other alkalis, […]
It has to do with the fact that atoms and molecules that are heated in flames can absorb some of the heat energy and then promptly spit it back out as light energy. Every substance has its own typical wavelengths or colors of light that it emits after being stimulated by the heat. (Techspeak: every […]
By capillary attraction, the wick leads melted wax up to where it can be vaporized and mix with oxygen in the air. A block of solid wax, or even a puddle of melted wax, won’t burn because the wax molecules can’t come in contact with enough oxygen molecules; only as vapors can they mix intimately, […]
Dogs’ hind legs move when they are scratched in certain spots for the same reason a person get shivers when someone touches his back or shudders when fingernails are scraped down a chalkboard. It’s a reflex. Some experts say it’s a method that dogs’ wild ancestors once used to scare away predatory animals looking for […]
The easiest way to understand the science involved is to float a metal bowl. While the metal itself is heavier than water and would normally sink like a stone, the shape spreads the weight over a large area. So, while the metal’s weight causes the bowl to sink somewhat, the bowl’s rim is high enough […]
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 […]
You don’t lose fat cells when you lose weight, the fat cells simply become smaller. In people who have an excess number of fat cells, the fat cells may be even smaller than normal when they get down to a normal weight. That may be one reason it is so easy to regain weight. The […]
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 […]
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 […]
Why Do Some Dead Bodies Get Preserved When They Are Buried and How Does Adipose Tissue Turn Into Adipocere?
Non-decay of a dead body is more common than most people think. Many saints have had their claim to sainthood upheld by the nifty trick of not going off after burial. More mortal examples include the wife of Dante Gabriel Rossetti, who troubled him somewhat by being revealed in all her undecayed glory when, short […]
The origins of Hurricane Sandy, one of the most costly superstorms ever, have been revealed by meteorologists. The storm caused over $20 billion (£12.5 billion) worth of damage and claimed more than 50 lives. Classified as a post-tropical cyclone, Sandy caused wide-scale destruction to buildings, left over 7.4 million properties without power and led to […]
I’ll assume that you’re in the dining room, concerned about soup on your necktie, although you may have noticed this phenomenon in other rooms under different circumstances. We see an object because light is coming from that object and entering our eyes. The more light coming from the object, the brighter it appears. And of […]
In addition to the hundreds of classic cheeses developed over more than a thousand years in various parts of the world, we are blessed today with many options for adding cheese flavor, be it natural or artificial, to our snacks and dishes. Dozens of cheesy (often in more ways than one) factory-produced concoctions beckon to […]
Some disease-causing organisms, or pathogens, can thrive and multiply for some time on an object like a phone receiver spattered by the saliva of an infected person. But most bacteria and viruses quickly die when moisture disappears, usually after one or two hours for the saliva spray. Different pathogens have different survival times, ranging from […]
It is not true to say that nature hasn’t invented the wheel. Bacteria have been using it to get around for millions of years. It is the basis of the bacterial flagellum, which looks a bit like a corkscrew and which rotates continuously to drive the organism along. About half of all known bacteria have […]
Sound travels faster in helium than in air because helium atoms, with atomic mass 4, are lighter than nitrogen and oxygen molecules, which are molecular mass 14 and 16 respectively. In the human voice, as in all wind instruments, the sound is produced as a standing wave in a column of gas, normally air. A […]