Plantains are tropical fruits closely related to bananas, both members of the genus Musa, but much starchier and containing much less sugar when ripe. They’re also known as cooking bananas, which is a clear tip-off that they’re not meant to be eaten raw. Plantains are a staple in Africa and especially in Latin America, where […]
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 […]
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 […]
A Depression flower garden is also called a coal garden or a crystal garden. It’s a homemade set of colorful crystals. They’re a lot of fun for kids and grown-ups, and are a hands-on way of learning about crystal formations. You begin by breaking up several charcoal briquettes and putting them into the bottom of […]
Multiply your weight by 2.4. That’s how much you weigh on Jupiter. For the sake of clarity, let’s say you weighed an even 100 pounds. On Jupiter, you’d weigh about 240. Multiply your same 100 pounds by .38 and discover that on Mercury you’d be about 38 pounds. On the moon (multiply by .17), about […]
Why Is Red Meat Red and White Meat White and What Is the Difference Between Red Meat and White Meat?
Red meat is red because the muscle fibers which make up the bulk of the meat contain a high content of myoglobin and mitochondria, which are colored red. Myoglobin, a protein similar to haemoglobin in red blood cells, acts as a store for oxygen within the muscle fibers. Mitochondria are organelles within cells which use […]
Why Are Traffic Lights Arranged Red Yellow Green From the Top and Why Are Railway Signal Colors Different?
The difference between road and rail signal color usage comes from the history of railways and the primacy of safety. The old mechanical railway signalling arms were designed so that failure, which would be in the “down” position, meant stop. The illuminated part of the signal consisted of two colored glass panels in the far […]
Sure, freezer burn is an oxymoron, but not a bad one at that. Take a good look at that ancient pork chop you’ve been keeping in the freezer for an emergency. Doesn’t its parched and shriveled surface look as if it had been seared? Believe it or not, “seared” doesn’t only refer to heat; it […]
The Peruvian coastal plain in South America is home to a wonder of archaeology. The ground is scarred by images, or geoglyphs, known as the Nazca lines, thought to have been constructed by the people of Nazca between 500 BCE and 500 CE. The ancient artworks, most easily viewed from the air, were created by […]
Male Emperor Penguins build up big fat reserves before nesting and slowly burn them off. At fifty or sixty pounds or more, emperors are the largest penguins, and their size means they can withstand cold better than smaller species and can “nest” the farthest south. They breed on the frozen Antarctic Sea, where temperatures may […]
The assumptions of the question are not totally true. It’s not just drinking, but where you drink and what kind of clothes you have on that determine whether the body ends up warmer or colder. What happens is that alcohol causes the blood vessels in the skin to dilate, so that more blood passes through, […]
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 […]
Why Does Ice Float On Water and Why Is Ice the Only Non-Metallic Substance To Expand When it Freezes?
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 […]
Sorry, but once the water has begun to boil, it’s as hot as it will ever get, even if you use a flamethrower. No matter how furiously you might get the water to boil, it won’t get any hotter than the boiling point of water: 212 degrees Fahrenheit (100 degrees Celsius), plus or minus. Let’s […]
Around 270 B.C., the Greek astronomer Aristarchus proposed that Earth and the other planets revolved around a stationary Sun. He was dismissed as a madman, until Copernicus. Copernicus studied the movements of the planets in the 1,400 years since Ptolemy and found that Ptolemy’s idea of epicycles, secondary orbits within the main orbit, could not […]
When the liquid carbon dioxide in the tank turns into gaseous carbon dioxide, it gets cold enough to freeze some of the carbon dioxide into “snow.” But why, indeed? All that’s happening is that the compressed carbon dioxide gas is expanding as we let it loose into the room. Do expanding gases automatically get cold? […]
Why Does a Kettle Whistle or Sing and What Causes the Note To Rise In Pitch, Then Fade and Fall In Frequency?
If you leave the lid off your electric kettle and switch on, you can see what is happening. The heating element quickly becomes covered with small silvery bubbles, each about 1 millimeter in diameter. These are air bubbles, forced out of solution by heat from the element. Rough parts of the element’s metal surface provide […]
Why Do Fish Jump Out of Their Tanks and What Is the Best Way To Prevent Fish From Jumping Out of the Tank?
Fish jumping out of tanks small or large is quite a common problem for enthusiasts, and is the reason why some owners choose to have a glass cover on the top of their aquarium. There are several theories as to why fish might jump from a small aquarium. It has been suggested that one reason […]
A global positioning system receiver is a pretty cool little gadget. It’s somewhat based on the navigational systems of old in which skilled sailors using compasses, astrolabes, and sextants could tell where they were (give or take a hundred miles) by combining the data of the stars, sun, and moon positions. Of course, there were […]
Why Do Dogs Howl and Bark When Emergency Sirens Pass By While Cats Do Not Seem To Care About the Noise?
The reason dogs yowl when emergency services go by may be that to the dogs, the siren sounds like other dogs howling and they respond by howling back. This goes back to the time when they hunted in packs and signaled to one another when searching for prey. Even if the screaming siren does not […]
Why Does Water From an Inverted Bottle Flow Faster At the End and What Causes the Different Flow Rates?
Water flowing from an inverted bottle has no free surface. So the water coming out has to be replaced by something else because liquids do not expand or contract very much when the pressure changes. In the case of a thin-walled plastic bottle, the volume can be replaced by the walls of the bottle being […]
Who Was Jane Goodall and How Is Goodall’s Work With Chimpanzees Important To Animal Conservation Efforts?
Jane Goodall was born in London, England, in 1934. As a child, she never liked school but she loved to read and, most of all, she loved animals. After graduating high school, she had a chance to visit Africa in 1960 and her life changed forever. On this trip, she met Louis Leakey. Even though […]
There’s a big difference between homeopathy and holistic medicine. Homeopathy comes from the belief that bringing on a small amount of the symptoms that all you will make you well, homeo means “similar” in Greek; pathos means “suffering.” Founded in the 1800s by a doctor named Samuel Hahnemann, the practice was born out of Hahnemann’s […]
Let’s start with the two basic principles that make modern refrigeration possible: The first rule you know already if you’ve ever inflated a tire using a hand pump and noticed that the pump was surprisingly hot afterward: Gases will heat up when you compress them. Conversely, gases cool down when you release pressure and allow […]
Yes, most beans make us gassy and fart. Blame it on the oligosaccharides, or, if you prefer, the dog. Oligosaccharides are a special sugar found in beans and other fibrous foods like soybeans, cabbage, peas, and cauliflower. These sugar molecules are very large and are not digested by the small intestines, so they pass on […]
Birds have a sort of thin extra eyelid called a nictitating membrane that protects their eyes and may do so in the rain. The membrane is not entirely transparent, so the birds may not see clearly, but they can probably see light and dark. As in cats, dogs and other animals, this membrane can flick […]
Only about 2.5 percent of a penny is copper. The layer is just thick enough to give the coin its distinctive copper color. Most of the penny is made with zinc, but that’s a relatively new development in the history of the coin. Before 1982, pennies were about 95 percent copper. So why the switch? […]
What Types of Tools Did Ptolemy and Other Ancient Astronomers Use To Calculate the Position of the Planets?
We know of at least three tools Ptolemy used in his calculation of the position of the Sun, the planets, and the stars. To measure the Sun’s position, he probably used a quadrant. A quarter of a circle was ruled on a square board and a special line was attached to make sure it was […]
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 […]
Microwaves aren’t radiation, they’re radio waves, so microwaved foods never become radioactive in the first place. The way microwaves work is that they have a strong effect on water, twisting its molecules back and forth rapidly. As the water molecules rub back and forth against other molecules, they heat up from the friction. Luckily nearly […]
Asians don’t actually have slanted eyes, that’s an optical illusion, as it were. Folks from Asia actually have an extra fold in their eyelids called the epicanthic fold. It’s at the top of the eyelid and is elongated, sometimes extending beyond the eyelashes. Caucasian or African eyes have a slight, shortened fold where the epicanthic […]
If we leave aside the possible presence of diseases like arthritis or diabetes, several mechanical factors could make standing still more tiring than walking. First, the action of the muscles in walking keeps the circulation of both blood and lymph going, preventing the pooling of fluids in feet and ankles. For another thing, when a […]
Scientists penguins would probably not survive if they were transported from their native environment in the Antarctic to the Arctic. For one thing, they would find none of the landmarks that they used to establish their ancestral breeding grounds. For another, they don’t defend themselves and their young well, they thrive so well in the […]
The air does keep getting colder, by an average of about 3.6 degrees Fahrenheit for every thousand feet (6.5 degrees Celsius per kilometer) , up to around 33,000 feet (10,000 meters) above sea level. That’s just a bit higher than the cruising altitude of large commercial jet aircraft. You may have heard the airliner’s captain […]
Bird droppings combine the whitish waste products processed by the liver and kidneys with the darker wastes that come from the digestive tract. In birds, the nitrogen-rich wastes are turned into a white-colored paste that is composed mostly of urates. The urates often form a separate white blob, as anyone who has worn a new […]
Why Do the Two Outer Panes of an Airliner Cabin Window Have a Piece of Cylindrical Metal Separating Them?
Airline windows typically comprise three or more layers of glass, or acrylic, to provide insulation from the very cold atmosphere at altitude. The tiny silvery cylinder is really the edge of a small hole drilled in the middle layer to allow the pressure to equalize between the layers while minimizing convection. The condensation around the […]