Karen Hill

The answer to why beer goes flat when it gets warm lies in the behavior of gases, and their solubility in water. Most beers are dilute solutions of sugars, gases, organic acids, and other complex compounds, and, hopefully, alcohols. The gas which gives fizzy drinks their distinctive fizz is carbon dioxide. In the case of … Read more

Navigation requires that you know where you are relative to your destination, and how to negotiate the route. To do this in space, knowing your attitude is as crucial as knowing your position, so the first thing to do is find and track the sun and a known, conspicuous, distant star. Sirius is a good … Read more

The magnetic field of the Earth looks like a dipole, the shape formed by iron filings around a bar magnet, although the Earth’s is rotated about the field’s axis to form a three-dimensional shape. This extends to about 40,000 miles into space. On the ground we use a compass in two dimensions. In space you … Read more

If the moon suddenly disappeared, it would unleash a devastating chain of events that would ultimately spell the end for life on Earth. The most immediate difference would be the disappearance of the tides. Both the sun and moon influence the tides on Earth, but the moon is the dominant force. Remove the moon and … Read more

Old bottles of Madeira wine don’t have to be stored in an upright position, but unlike other wines, it won’t do them much harm. Once wines have been bottled, oxygen becomes the enemy. It oxidizes the wine, resulting in an unpleasant odor and taste. The purpose of the cork is to keep out all oxygen … Read more

The simple answer to why black tea changes color is that adding lemon juice alters the acidity of the tea and the color change is an indication of this. The color change is the same way that litmus paper changes color. A similar effect can be observed by substituting the tea with some cooked red … Read more

If you applied an absolute vacuum above a nonvolatile liquid, then the maximum height you could suck it up a vertical pipe would be reached when the hydrostatic head pressure of the column of liquid equals one atmosphere (101,325 pascals). This pressure is given by p x g x h, where p is the fluid … Read more

The earliest fabric softeners were developed during early 20th century and were based on a water emulsion of soap and olive oil, corn oil, or tallow oil. Static build-up in clothing is caused by fiber-to-fiber, fiber-to person and even fiber-to-air friction, and depends on the type of fiber from which the garment is made. The … Read more

Many folks have assured us that their bread doesn’t have time to go concave when spread with honey. However, for those folk who chomp their honeyed bread in a more leisurely fashion, there is a simple explanation. Bread is approximately 40 percent water while honey is a strong solution containing approximately 80 percent sugar. This … Read more

The graying of the inner surfaces of incandescent bulbs is the result of gradual evaporation of tungsten from the filament while the light is on. This evaporation eventually makes the filament so thin it burns out. Various methods have been developed to reduce graying. Filaments of the first incandescent lamps burnt in a vacuum, but … Read more

The way in which the unique Aero bubbles are added is a top-secret process closely guarded by Nestle Rowntree. We can tell you, however, that there are approximately 2,200 bubbles in one Aero chunky bar. Secret details may be absent but the broad answer is in Rowntree’s British patent GB 459583 from 1935. The chocolate … Read more

Tia Maria is a coffee liqueur made originally in Jamaica using Jamaican coffee beans. It is beautiful to watch patterns form on the layer of cream on a Tia Maria, and how different patterns form in layers of cream of different thickness. This is all caused by convection. Convection is the bulk movement of fluid, … Read more

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 … Read more

Unopened jars of honey that have remained clear for years can, over the space of a couple of weeks, change into solid sugar while the jar remains motionless on its shelf. Temperature does not seem to be a factor, the process can occur in winter or summer. Beekeepers argue about this, as honeys from different … Read more

Monosodium glutamate is a common flavor enhancer that is used particularly in Chinese and Japanese cooking. Monosodium glutamate, or MSG, is presumably most commonly used in oriental cooking for traditional reasons. For thousands of years the Japanese have incorporated a type of seaweed known as kombu in their cooking to make food taste better. It … Read more

Dyes used in toilet paper or paper towels are not very ecologically harmful or destructive. Chemically active groups on the dye molecules cling to the cellulose; that is why the colors don’t run and leave you fundamentally decorative after you apply them. The dyes are like a mousetrap that has caught a mouse: the trap, … Read more

Gnocchi is a variety of thick, Italian dumplings made from semolina, wheat flour, potato, or bread crumbs. Gnocchi is yummy when it is soft, airy, light, and “fluffy”. The word gnocchi means “lumps”, and is a traditional Italian pasta type introduced by the Roman Legions during the expansion of the empire into the European continent. … Read more

There is no known inventor of the pickle, because pickling has been around for a very long time. Pickling was a way to preserve food for out of season use and for long journeys, especially by sea. Pickles and chutneys were originally a means of preserving fruit and vegetables using a combination of heat processing … Read more

Natural rubber is made of polyisoprene chains that slip past each other when the material is stretched. When raw, the substance is too sticky and soft to be of much use, so it is toughened with the addition of chemicals such as sulphur that create cross-links between the chains, making the rubber stiffer and less … Read more

Here’s why some fruit and plant tissues go brown when cut. Plant cells have various compartments, including vacuoles and plastids, which are separated from each other by membranes. The vacuoles contain phenolic compounds, which are sometimes colored but usually colorless, while other compartments of the cell house enzymes called phenol oxidases. In a healthy plant … Read more

In the interest of science a Guinness was poured in a glass until the rising bubbles had formed a creamy head. Some of this was put in a dish and examined it through a low-powered microscope. Unlike bath foam, which has many semi-coalesced bubbles, Guinness foam is made mainly of uniformly sized, spherical bubbles of … Read more

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, … Read more

The lowly wasp certainly has its place in the food chain. Many animals feed, in one way or another, on this lowly and potentially dangerous insect. Here are a few creatures that do eat wasps, the first list being invertebrates. Several species of dragonflies (Odonata); robber and hoverflies (Diptera); wasps (Hymenoptera), usually the larger species … Read more

The United States Department of Agriculture states that a 180 g serving of boiled spinach contains 6.43 mg of iron. The reason you should you always use a stainless steel knife to cut your spinach is intriguing and is a major stumbling block to the fortification of food with iron. Remember that a lack of … Read more

When water vapor condenses on a dry mirror, it does so as separate droplets, a process known as dropwise condensation. The numerous drops effectively screen the mirror so that it appears opaque. When you draw on the surface with your finger, the droplets coalesce into a thin film of transparent water, so the mirror becomes … Read more

Shandy, also known as shandygaff, is beer flavored with carbonated lemonade or ginger ale. If you pour lemonade and beer into separate glasses you will notice that only the beer forms a head. That is because beer contains surfactants, proteins, and other long-chain molecules that help liquid films to form and stabilize bubbles. Lemonade bubbles, … Read more

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 … Read more

A study in 1987 examined injuries and mortality rates in cats that had been brought to their hospital following falls ranging from between two and 32 stories. Overall mortality rates were low, with 90 percent of the cats surviving, a fact that supports many ailurophobics. However, the study unexpectedly found that the incidence of injuries … Read more

Pineapples aren’t eaten in the state that we normally see them but are eaten after they have ripened much further and fallen to the forest floor. The pineapple, Ananas comosus, was originally found in south Brazil and Paraguay and indigenous peoples spread it throughout South and Central America and to the West Indies. The plant … Read more

Many elementary school boys have a great interest in all aspects of the decomposition side of the food chain. It is difficult to predict precisely how fast a guinea pig or any other animal will decompose. Farmers, especially those who raise livestock, bury a lot of small animals over the years. They also prepare many … Read more

When the lead bird completes a flap of its wings two vortices are shed, one from each wing tip. These vortices consist of a rolling tube of air, the upper portion of which is moving forward and the lower part rearward. Should a following bird complete a downward stroke into the top of a vortex, … Read more

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 … Read more

Snails both fertilize and carry their eggs internally. When snails are being prepared before being eaten, the snails are scooped out of their shells; usually mixed with butter, parsley, and garlic; then cooked. After cooking they are reinserted into their shells and served. The shells themselves are not cooked, so sometimes baby snails will later … Read more

Potatoes are a member of the Solanaceae family of plants, which includes tomatoes, peppers, eggplants, tobacco, and deadly nightshade. They are characterized by their ability to produce toxic alkaloids such as solanine in their leaves, roots, and fruit. Unfortunately, solanine does not dissolve, so it cannot be removed by soaking the potato and it is … Read more

The absence of trees in most chimneys shows that a very favorable site is required for growth. Damaged brickwork can provide a crevice for a seed to lodge in and send down a root, usually during a particularly wet year. The extra wetness permits the roots to go deep enough into the brickwork to survive … Read more

The depth and extent of the tunnel system of a mole, also known as Talpa europaea, will vary considerably depending on a number of factors such as the type of soil and the height of the local water table. Earthworms and other invertebrates that enter the tunnel system are the moles’ main source of food, … Read more

Giraffes and camels have long legs, relatively short bodies, and large feet. A common explanation for their unusual gaits is that the gait prevents fore and hind feet from getting in each other’s way. If you refer to feet by their initials, LF for left fore, RH for right hind, and so on, you can … Read more

Beheading hurts. How much it hurts depends on the executioner’s skill, or lack of it. When Mary, Queen of Scots, was executed at Fotheringay Castle in 1587, a clumsy headsman gave her three strokes without quite managing to sever her head. The headsman then had to saw though the skin and gristle with his sheath … Read more

The reason that we can’t see clearly underwater is the same reason a spoon looks bent when you immerse it in a glass of water. Light travels more slowly through water than it does through air. When light moves from one medium to another, it changes speed, and as a result the beam is bent, … Read more

The microorganisms that inhabit the body of a healthy human being are known as the normal microbial fauna and they come in two different types, those that are permanently resident and those that are transient. Of course, any number of fascinating and nasty parasites can join this microbial community and make the human body their … Read more

Millipedes and earthworms have similar lifestyles. Both burrow in soil, eating dead and decaying vegetation, but they have evolved very different methods for forcing their way through the soil. Worms use the strong muscles in their body walls to build up pressure in the body cavity, and so develop the forces needed to push forward … Read more

Some of us have birdbaths in our garden with a large plastic receptacle fashioned from a plant-pot saucer to hold the water. Many birds use it each day, but it is common to have algae build up very quickly on the surface covered by the water. This can happen even if the plastic receptacle was … Read more

Flies are often a nuisance while sitting on the hotel balcony when you’re on vacation. But when the winds pick up, the flies disappear. There is indeed a maximum wind speed above which they will not fly, but it also depends on temperature, humidity, and the sex and age of the fly, as well as … Read more

In the nineteenth century, bromide salts were used widely as sedatives to treat everything from epilepsy to sleeplessness. The bromide salts were said to “reduce the excitability of the brain.” The normal dose was between 5 and 30 grains and was taken several times a day, there are about 437 grains per ounce. In the … Read more

Miraculous claims of cellulite removal are characteristic of quackery, one of the biggest parasitic industries on the planet, ranking with politics, recreational drugs, and bad-faith litigation. The word “cellulite” was coined to exploit rich innocents. It has no clear definition, and that is why quacks say so little about what it is. Cellulite amounts to … Read more

Your butt does look smaller when you dress in black, at least if viewed from behind. The reason is that we can perceive shapes only if what we see appears in different shades or colors. If you wore white trousers the shape of your behind could be inferred from the slight shadows cast by its … Read more

There are many situations in which a wiping or rubbing action becomes converted to a high-frequency vibration, and the usual reason is the stick-slip nature of friction. When you start to push one surface over another, friction resists the movement. But if the pushing force is increased, it eventually reaches the threshold at which friction … Read more

Umbilical cords consist of three blood vessels and a surrounding medium called Wharton’s jelly, the whole lot enclosed by a sheath. This makes the cord too thick to be tied in a knot. Today, where medical supplies are readily available, a plastic clamp is used to compress the cord and cut off the blood supply. … Read more

One of the major functions of the colon is to absorb water and produce plasticine-like poop or feces which can be voided readily and at will. Feces consist of 75 percent water; bacteria make up half the dry weight; and the rest is unfermented fiber and excreted biliary compounds. The range of fecal weights produced … Read more

The scientific term for the yellowish crystalline substance sometimes found encrusted on eyelids when you wake up is “Rheum”, or gound. It is also commonly referred to as “sand” or “sleep”. Some amount of dry mucus forming in the corners of the eyes is common even among healthy individuals, especially children. The substance collects around … Read more

About 2,000 sebum-producing sebaceous glands and specialized sweat-like apocrine glands in the outer third of the ear canal produce mildly acidic secretions, called cerumen. Earwax is a mixture of cerumen, skin cells, and hair fragments from the ear canal, plus bacteria and other substances caught in this waxy matrix. Earwax normally moves out of the … Read more

Athlete’s foot, also known as ringworm of the foot, is a fungal infection of the skin that causes flaking, scaling, and sometimes severe itching of affected areas. The Infection is commonly transmitted in moist areas where people walk barefoot, such as showers or bathhouses. It can also be transmitted by sharing footwear and even towels … Read more

Measuring the weight of your head involves effectively isolating it from the rest of your body. Decapitation has the obvious disadvantage of your not being alive to see the results. However, there is a solution. Your neck vertebrae are responsible for holding your head’s weight. If you hang upside down from your feet the vertebrae … Read more

The equivalent of the true appendix in most animals is known as the cecum and is at the junction of the small and large intestines. In general, carnivorous mammals have a small cecum that serves the same purpose as it does in humans. However, in many herbivorous mammals the cecum is greatly enlarged to create … Read more

Snake venom is dangerous and should be treated with extreme caution and not ingested in any form. We have watched a Zambian snake expert, Major Alick Chanda, milk the venom from a live puff adder (Bitis arietans) into a wineglass and drink it, with no ill effects. Snake venom is a complex mixture of proteins, … Read more

Beer has had a reputation since antiquity as being a staple in the diet, often called “liquid bread.” In ancient Egypt, workers received beer as part of their salary, as did the ladies-in-waiting of Queen Elizabeth I of England. In 1492, one gallon of beer per day was the standard allocation for sailors in the … Read more

Some people have alopecia, so they don’t have eyebrows. In warm weather, sweat runs into their eyes and makes them sore; in wet weather they have to keep wiping the rain out of their eyes. Your eyebrows divert sweat droplets and raindrops from running directly into your eyes. You would be very uncomfortable without them. … Read more

The damage a bullet does to its target is measured in two ways: the depth of penetration and the amount of tissue damage per inch of penetration. These two figures are normally found by firing live rounds into blocks of a thick, viscous gel that is formulated to have the same physical properties, such as … Read more

A hard, mineralized exoskeleton and a marine lifestyle would have given you a better chance of being a fossil. But let’s start with what you have got: an internal skeleton and some soft outer bits. You can usually forget the soft bits. If you take up mountaineering or skiing and end up in a glacier … Read more

Running is a form of eccentric exercise, meaning that the muscle is forced to lengthen while trying to contract. Prolonged or unaccustomed eccentric exercise often leads to pain, tenderness, and stiffness in the muscles hours or even days later. This is known as delayed onset muscle soreness and is very common. The sensation of discomfort … Read more

As with all musical instruments, the quality of the human voice is largely determined by resonance. A great Italian tenor gave permission for his larynx to be studied after his death. Air blown through his isolated vocal cords produced the same noise, somewhere between blowing a raspberry and the sound of a whoopee cushion, as … Read more

A bruise occurs when small capillary blood vessels break under the skin. The hemoglobin in this leaked blood gives the bruise its classic red-purplish hue. The body then calls in white blood cells to repair the damage at the site of the injury, causing the red cells to break down. This causing produces the substances … Read more

A leaflet published by Health Scotland says the darker the color of the alcoholic drink, the worse the hangover would be. Most people consume alcoholic drinks for their ethanol content. However, many such drinks also contain amounts of other biologically active compounds known as congeners. Congeners include complex organic molecules such as polyphenols, other alcohols … Read more

Coincidence seems likely when there are more baby girls born than boys in any given family, and vice versa. Any fetus has approximately a 1-in-2 chance of being female; the chance of seven children all being girls is therefore 1 in 2 to the seventh power, or 1 in 128. These are not particularly long … Read more

Clear air turbulence, or CAT, is real and often quite scary. Pilots are unable to see CAT, and it can indeed cause an aircraft to crash, especially if encountered just after take-off or just before landing. Since 1981, there have been more than 350 reports of aircraft running into serious turbulence. It is also considered … Read more

An entry in the local school logbook for the village of Nash in north Buckinghamshire, dated November 9, 1917, states “Letter of thanks received from the Director of Propellant Supplies for chestnuts gathered for the making of munitions.” Chestnuts were used in the First World War for the production of acetone which, in turn, was … Read more

The story about an ornamental cactus releasing spiders is a popular myth. Such an event is particularly unlikely to involve tarantulas, which might possibly lay eggs or build webs on, but not in, a cactus plant. Tarantulas live in burrows in the ground, especially the female, which rarely moves around on the surface. Tarantulas take … Read more

There isn’t really a big difference between the ribs of men and women. The idea comes from the Old Testament account of the creation of Eve from Adam’s rib. However, the main sex difference is that women’s ribs are a little smaller on average. The bones forensic anthropologists really look at, the most reliable ones, … Read more

Whirlpools that swallow ships don’t occur in the ocean. However, eddies, or strong currents, can be one hundred miles across in certain parts of the ocean. They do not suck anything down or push anything up at a speed that you would notice, and while they could overturn a small boat, they could not swallow … Read more

A curve ball travels in a sideways arc, a very small segment of a very large circle, as Dr. Lyman J. Briggs found in a historic study in 1959. Then eighty-four, a retired head of the National Bureau of Standards, he settled the question and explained the mechanism, using an overhead camera to show the … Read more

Pinching the bridge of the nose and putting ice on the back of the neck to stop a nosebleed is an old wives’ tale. The pressure is a good idea, and in fact continuous direct pressure at the bleeding site is the only infallible remedy, but there is no use pinching the bridge of the … Read more

Dew is more likely to form if the sky is clear and in a similar folk rhyme: When the dew is on the grass, Rain will never come to pass; When grass is dry at morning light, Look for rain before the night. The effect is linked to the absence or presence of clouds. For … Read more

It is possible to make an egg stand on its end during the Equinox. But anyone who can stand an egg on end at that time can probably do it at any other time as well. The theory is that it is possible to stand an egg on its end during the vernal and autumnal … Read more

Modern medicine may have sent the death rattle the way of milk fever, the vapors, consumption and other layman’s terms for the ills of our ancestors. Many pulmonary diseases that can cause noisy labored breathing before death are not the major killers they were before antibiotics. And the kind of breathing distress that would cause … Read more

The moon is not actually larger when it is on the horizon, but seems larger because of an optical illusion. When the moon is on the horizon, it is seen next to buildings or trees, terrestrial items you are familiar with, and the juxtaposition of the two images changes depth cues. You know the building … Read more

No you can’t see stars in daylight from the bottom of a deep well, but you might be able to see some planets if you know where to look. One might think, using superficial common sense, that by excluding as much daylight as possible, one should be able to see stars in the daytime, but … Read more

There are no snakes in Ireland now, and no fossil records of snakes are known. This does not prove that there were never any snakes, because there is also no fossil record of the common lizard, which does occur in Ireland. But herpetologists presume that if there ever were any snakes, they were exterminated by … Read more

Blood doesn’t thicken in winter, even though it may sometimes feel like it. In fact, it might tend to be thicker in summer, when the body loses water through sweating and people need to drink more to remain hydrated. Temperature is not the chief regulator of the thickness of blood. It depends on the kidneys, … Read more

The Lion’s mane jellyfish, also known as Cyanea capillata, has long golden-yellow streamers of poison cells. The cold-water jellyfish might resemble a huge lion’s mane, just as Sir Arthur Conan Doyle described it in “The Adventure of the Lion’s Mane”. Its poison acts like a neurotoxin, and the effect is paralysis. The average swimmer need … Read more

There should be no difference if you play the same numbers each week or if you change the numbers every week. If you are flipping a coin or throwing dice, the outcome should be totally independent each time. This, of course, depends on the randomness of the numbers. There might be some oversight in the … Read more

There is very little information on the transmission of infectious diseases after death. But there is probably little or no danger that most disease organisms would survive even a few weeks in the inhospitable environment of the average grave. For survival, a certain organism needs a certain temperature, a certain level of acidity or lack … Read more

Depending on what kind of snow it is, we may be able to smell the wind that heralded it. One kind of snow results from warm, moist air gliding over cold air near the ground, and that kind is typically accompanied by southerly winds. Such storms are big snow producers, and depending on geography, these … Read more

The moon sometimes does turn red when it sets, and for the same reason the sun does. The light sent to earthly eyes, in the case of the moon, reflected sunlight, is seen filtered through a layer of polluted air, and the path through the dirty air is longest when the heavenly body is at … Read more

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, … Read more

There is some truth to the rhyme “Red sky at morning, sailors take warning, red sky at night, sailors’ delight”. The trick is to look at the part of the sky where the sun isn’t, not into the sunset but to the east. Both sunrise and sunset are reddish, as a rule, because of what … Read more

There is just a grain of truth in the idea, as green plants do absorb some oxygen for use in respiration, the mirror image of photosynthesis. Photosynthesis can occur only when there is light, so at night plants are absorbers of oxygen, on balance. However, true danger would result only from an extremely large body … Read more

Hair can’t turn gray overnight, but a head of hair can go gray very quickly when a person has a lot of gray already and loses all the dark hair. Hair is made of dead cells, and you can’t change the color in a dead structure unless you dye it. However, if a person is … Read more

Everyone has heard the rumor, but probably only dogs, or passing wolves, ever enjoyed a modern feast of preserved mammoth meat. Mammoth meat looks like horse meat but quickly rots when it thaws. Several mammoths were found in permafrost, preserved since the last glacial period. The most famous was found in 1901 near the banks … Read more

Modern science offers little support for the ancient belief in lunacy, or moon-engendered madness during a full moon. Despite anecdotal reports, epidemiological studies find no consistent correlation between any phase of the moon and any aberrant activity. Moreover, because of the distance of the moon, not to mention other heavenly bodies, and the infinitesimally small … Read more