The stuff in the dryer sheet happens to be good at both jobs. You can obtain the static-elimination function all by itself as a liquid in a spray can, so you can de-static your clothing even while you’re wearing it without your having to, DO NOT TRY THIS AT HOME!, climb into the dryer. The […]
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 […]
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 […]
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 […]
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 […]
It is true that men don’t have as much of the hormone estrogen as women. But the male hormone androgen, which normal men have in considerable supply, appears to exert similar protective effects on the skeleton. Men who have an insufficient supply of androgen do get osteoporosis, the loss of bone mass that often occurs […]
How Is It Possible For Vegetarian Children To Get Enough Calcium From a Diet With No Eggs, Fish or Milk?
It might be difficult, but it is not impossible for the child of strict vegetarians to get enough calcium from a diet that does not include eggs, meat, fish or milk products. The recommended daily allowance of calcium for children is 600 to 1,000 milligrams, depending on age. Many fruits and vegetables contain significant and […]
What Is the Best Way To Whisk Egg Whites and Why Do Regular Eggs Whisk Better Than Organic Free Range Eggs?
The best way to whisk egg whites is with large continuous strokes and conviction in a clean copper bowl with a large whisk with very thin wires made of stainless steel. We regularly whisk organic free-range egg whites without any problem, and bearing in mind that in culinary history all eggs could once have been […]
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 […]
Alexander Graham Bell invented many things, including a man-carrying kite, a land-mine detector, the hydrofoil boat, takeoff and landing gear for the airplane, and the aileron, a part of an airplane wing that moves and helps control rolling. He was also a co-founder of the National Geographic Society.
Sun flares are massive explosions on the sun with enough force to burn through the upper layer of Earth’s protective atmosphere. The flares are magnetic, so Earth’s magnetic field is able to protect us from the huge amount of heat and energy. However, the flares can still manage to disrupt activity on Earth’s surface for […]
Astronomers use two impact hazard scales to describe the risks associated with Near Earth Objects (NEOs). The simpler Torino Scale runs from 0 to 10. Objects rated 0 are either highly unlikely to strike Earth, or too small to survive the passage into the atmosphere, while an object meriting a 10 would be a certain […]
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 […]
What Is Dark Matter and How Did Vera Cooper Rubin’s Work On Galaxies Lead To the Discovery of Dark Matter?
In the 1970s, Vera Cooper Rubin started what seemed like an innocent experiment with another American astronomer, Kent Ford. Rubin wanted to determine why spiral galaxies differ in structure. She decided to compare the movements of stars near the center of a galaxy with those in the outer reaches of the galaxy. Rubin chose the […]
In 1696, the Swiss mathematician Johann Bernoulli challenged the scientists of the world to solve a problem he proposed. It was a very difficult problem, so he allowed six months for the solution. At the end of the six months, there were no solutions. The German mathematician, Gottfried Wilhelm Leibniz, who is given credit along […]
Indian yellow was first introduced in the 1750s and quickly became a staple of every artist’s palette because of its rich yellow hue. To get the deep color, manufacturers fed mango leaves to cows, collected their urine, and made a concentrate from it. In 1908 officials decided that feeding large quantities of mangoes to cows […]
How Much Water Do Clouds Hold and How Does the Size and Color of a Cloud Affect How Much Water It Can Hold?
The amount of water inside a cloud is not different from the amount of water in the clear air around it. However, while the clear air contains water vapor, inside the cloud the air is saturated with water vapor and it has condensed out to produce the cloud. The difference between the two states is […]
Antarctica is Earth’s coldest, driest and windiest continent, but many resilient life forms have adapted to survive the harsh environment. Among them is Earth’s tallest penguin, the largest mammal and the Antarctic icefish – the only bony animal with transparent blood. The coldest temperature ever officially recorded was on a high snow plateau in Antarctica, […]
The young Englishman Charles Darwin came from a family of wealth. Both his grandfather and father were successful physicians. He was supposed to follow in their footsteps, but the first time he saw surgery being performed, he had to leave the room. At 22, he received a theological degree but soon announced he had no […]
ARDS, which stands for acute respiratory distress syndrome, or sometimes adult respiratory distress syndrome (to distinguish it from a lung problem in newborns), is not a disease itself, but a type of severe acute lung dysfunction that can result from disease or injury, according to the ARDS Support Center, a clearinghouse for information. The condition […]
How Was the HMS Challenger Warship Modified For Charles Wyville Thomson’s Scientific Expedition In 1872?
The British government provided Charles Wyville Thomson with the HMS Challenger warship for the Challenger expedition. It was a 200-foot sailing ship, but it was equipped with a 1,200-horsepower engine to power dredging experiments. All but two of the ship’s 18 guns were removed and replaced with scientific laboratories and storage space. The ship had […]
It isn’t. Satellites and space shuttles do indeed get cold up there, but it’s not because it’s cold up there. First of all, there’s really no such thing as cold, no matter what the penguins tell you. Cold is a linguistic concept, not a scientific one. Our caveperson ancestors needed a word for “not hot,” […]
The difference between simmering and boiling is more basic than just the vigor of the bubbling. A simmer aims to produce a slightly lower temperature than true boiling, because even a few degrees difference in cooking temperature can make a big difference in how things cook. In moist cooking, cooking with lots of water present, […]
“Water seeks its own level” is a catch phrase that was probably uttered by a Greek philosopher two thousand years ago, and people have been parroting it ever since. In plain language, it means that water will lie flat whenever it can. If a body of water, anywhere from a bucket to a bathtub to […]
It’s not true that an hour of sleep before midnight is worth two hours of sleep after midnight. Sleep needs are much more complicated than that. The hour of rising is probably much more important in keeping sleep cycles normal. Individuals go through a series of periods of rapid-eye-movement, or REM, sleep, and non-REM sleep, […]
Right on. When it is winter on the part of the Earth where you live (northern or southern hemisphere), your hemisphere is leaning away from the sun a bit. That is, the axis of the Earth wobbles, so that during winter in the northern hemisphere the North Pole is farther from the sun than the […]
The technology in a fax machine is pretty simple. A bright light reflects off the document as it passes along a strip containing hundreds of tiny photocells. If a white area of the page passes below, the photocells convert the light shining off the document into electricity. If the area is black, the photocell generates […]
Although it can be difficult to know with certainty, there are clues in the shape and size of bony landmarks on the skull. You usually can’t sex other bones reliably, except for the pelvis. With the skull, what scientists look for is the difference between what is called robust morphology, meaning typically heavier, larger shapes […]
Let’s look at how chocolate is made. Cacao beans, which are really seeds, are found inside melon-shaped seedpods attached directly to the trunk or thick branches of the tropical cacao tree. The beans are first separated from the pulpy mass inside the pod and allowed to ferment, usually by piling them up in heaps 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 […]
Why Does the Water Level Rise When a Lit Candle Standing in Water Is Covered By an Upturned Glass Jar?
The seemingly well-understood candle experiment demonstrates how young and inquisitive minds are able to demolish false explanations propagated through school physics over the decades. The consumption of oxygen may well contribute to the rising water level to a certain extent, because a given mole volume of oxygen will burn the wax’s carbon into roughly the […]
Compounds containing cyanide can be found in some fruit pit kernels and some other foods as well. Even cabbage, broccoli and cauliflower contain cyanide compounds, but not enough to make them unsafe. Too many fruit pits can add up to a real risk, however. Apricot pits, for example, contain a compound called amygdalin, the supposedly […]
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 […]
Some birds do hit branches when they fly, but most are very maneuverable. Birds also have excellent vision, and the flight pattern and style, musculature and aerodynamic characteristics, and even how fast they fly, are adapted to the environment in which they fly. Birds that live in the forest and fly through the canopy are […]
Over 1 million cars are scrapped every year, but this is not the end of their life. Cars contain a wide variety of valuable metals that can be recycled and reused. Powerful car crushers compact the scrap steel, making it much easier to transport for the recycling process. Modern car crushers tend to employ hydraulics […]
Good try, but you used the wrong sugar. Ordinary table sugar is “granulated,” meaning that it consists of individual granules or grains, each of which is a single crystal of pure sucrose. But when pulverized into a fine powder, sugar tends to pick up moisture from the air and cake. (Techspeak: sugar is hygroscopic.) To […]