One morning I decided that I wanted to learn a new thing every day. So I decided to share my experience with everyone.

Tuesday, July 31, 2007

Coffee against UVB

A moderate cafeine consumption and physical exercise would prevent the carcinogenic effects of the exposure to the ultraviolet radiations B of sun (UVB). Tests carried out on mice by researchers of Rutgers University show that this combination destroyed the cells whose ADN had been damaged by the UVB.

The study was carried out on mice particularly vulnerable to the rays of the sun. Four groups of rodents were created. The first group drank water containing cafeine (the equivalent of one or two coffee cups for the human). Another group made exercise, and third one combined both. A fourth reference group did not introduce cafeine and did not make a exercise. All the groups were exposed to UVB rays . The results show that the group that did both exercise & cafeine had a definitely higher capacity of destroying damaged cells than the other groups. The complete results are published in the review Proceedings for the National Academy of Sciences (PNAS).

Monday, July 30, 2007

Wind Chill & Heat Index

To understand wind chill, one must have some appreciation of the concept of a thermal boundary layer. If you dive into the ocean and come back out again, a thin layer of water will adhere to your skin. We live in an ocean of air, and air, like water, can be said to “wet” the skin or any other object that is immersed in it. Right at the surface of the skin, the adhering air is still. Because air has some internal stickiness (viscosity), there is drag between the adhering air and the air molecules farther away from the skin. As a result, near the skin or any surface there is a zone of relatively still air that may be several millimetres thick. This is the boundary layer.

The boundary layer insulates your skin from the environment. If you blow on your arm, it can feel cool even though your breath is relatively warm because you have blown away the warm boundary layer air that was insulating the skin. If you do the same experiment in a hot sauna, instead of feeling cool, the spot you blow on can feel painfully hot, because you have blown away the boundary layer of sauna air that had been cooled by the skin and allowed the heat of the sauna to reach the skin more easily.

The Heat index (or humidex) is an index that combines air temperature and relative humidity to determine an apparent temperature — how hot it actually feels. The human body normally cools itself by perspiration, or sweating, in which the water in the sweat evaporates and carries heat away from the body. However, when the relative humidity is high, the evaporation rate of water is reduced. This means heat is removed from the body at a lower rate, causing it to retain more heat than it would in dry air. Measurements have been taken based on subjective descriptions of how hot subjects feel for a given temperature and humidity, allowing an index to be made which corresponds a temperature and humidity combination to a higher temperature in dry air.

For example, at 80 °F (approximately 27 °C), the heat index will agree with the actual temperature if the relative humidity is 45%, but at 110 °F (roughly 43 °C), any relative-humidity reading above 17% will make the Heat Index higher than 110 °F. Humidity is deemed not to raise the apparent temperature at all if the actual temperature is below approximately 68 °F (20 °C)

Friday, July 27, 2007

Diary of a Killer Cat

Ok, I wasn’t going to talk about it, because this is not the kind of article I usually discuss in my blog, but since yesterday I saw this article at least half a dozen times and it even made the 6 o’clock news. And since it from the New England Journal of Medicine, I decided to talk about it, just to add my own explanation.

From the article on Yahoo!

“Oscar the cat seems to have an uncanny knack for predicting when nursing home patients are going to die, by curling up next to them during their final hours. His accuracy, observed in 25 cases, has led the staff to call family members once he has chosen someone. It usually means they have less than four hours to live.”

You can read the full article here: http://news.yahoo.com/s/ap/20070726/ap_on_fe_st/death_cat;_ylt=AmR5dcvU_SgPvsrcjCBhdt3q188F

I got ton of explanation for that:

Maybe it’s a psychological effect. The first time it happen it was a lucky shot and the rumor start off that this cat can predict death. Then once the cat was in your room, you were so sure that you gonna die, that you let yourself go.

Or even worst, maybe all theses people where actually allergic to cats and the cat simply kill them by staying by their side.

Thursday, July 26, 2007

Déjà Vu

Ever wonder how the strange déjà vu feeling happen? It’s had nothing to do with someone changing something in the matrix.

The term "déjà vu" (French for "already seen", also called paramnesia from the Greek word para for parallel and mnēmē for memory) describes the experience of feeling that one has witnessed or experienced a new situation previously. The term was coined by a French psychic researcher, Émile Boirac (1851–1917) in his book L'Avenir des sciences psychiques (The Future of Psychic Sciences), which expanded upon an essay he wrote while an undergraduate French concentrator at the University of Chicago. The experience of déjà vu is usually accompanied by a compelling sense of familiarity, and also a sense of "eeriness", "strangeness", or "weirdness". The "previous" experience is most frequently attributed to a dream, although in some cases there is a firm sense that the experience "genuinely happened" in the past. Déjà vu has been described as "remembering the future."

Basically, the brains receive many inputs (vision, smell, taste, etc). Under the normal process, all theses inputs are send in the conscious part of the brain. Then they are compared to what it is stored into your memory. Then the events (the collection of all the inputs at this moment) are stored into memory. This whole process only take a few milliseconds. This is who you can recognize your house or your lover. A déjà vu happen when the events (the inputs) would be stored into memory before the conscious part of the brain even receives the information and process it. This trigger the strange feeling of déjà vu because when the conscious part of the brain interrogate your memory for similar information, your memory will told you that an exact copy of this information is already stored … leading you to believe that this particular event have somehow already happened in the past.

Wednesday, July 25, 2007

Boom, Here comes the Boom.

Actually, there is not just a single boom; as long as an aircraft is moving faster than sound through the atmosphere, a sonic boom can be heard each time the surface of a cone-shaped shockwave intersects with a set of eardrums.

Many authorities suggest that what happens in three dimensions in the air can most easily be visualized by watching the waves produced in front of a boat in the water, with the boat moving through them. If the boat is traveling at a great speed, the water cannot get out of the way of the bow, and the compression of the waves in front of it increases, producing great turbulence that collects as a V-shaped wave spreading in the wake of the boat.

For an airplane, the waves are sound waves, alternating areas of compression and rarefaction of the air. The waves are pushed closer and closer together as the plane flies faster and faster, again creating great turbulence and buffeting.

If the plane reaches speeds faster than the speed of sound, the turbulent waves collect in a cone-shaped wake, with a boom audible along its surface. The sound owes its explosive quality to the sudden, rapid changes in air pressure along the surface of the cone.

Tuesday, July 24, 2007

Bite Me

Today, I was browsing random article on wikipedia. I usually don’t find anything really interesting using this method (and today’s no exception), but I was struck by the complexity of the article title: Gnathodynamometer. God, who comes up with theses names ?

A gnathodynamometer is apparently an instrument for measuring the force exerted in closing the jaws. Better yet, there’s an adjustable version called a bimeter gnathodynamometer (with an adjustable central-bearing point).

As per the inventor's (JN Snodgrass) design study, the instrument works well "in measuring maximal bite force and masticatory efficiency of incisor and molar teeth, respectively."

Experiments carried out with a Snodgrass gnathodynamometer at the Lerner Marine Laboratory in Bimini, Bahamas revealed that a 2m 6ft 6 ¾ in long dusky shark (Carcharhinus obscurus) could exert a force of 60 kg/132 lb between its jaws. This is the Strongest Bite Guinness World Record.

Now, this is what I call a crappy job … I don’t known how much the guy that is installing the gnathodynamometer into the shark mouth is being paid, but I sure that it’s ain’t enough.

Monday, July 23, 2007

Driving Direction

Why does people drive on the left in England? First let's put some fact on the table. England is not the only places where people drive at left. In fact most countries that was part of the British Empire also drive left. This include part of Africa, Australia, etc. About 34% of the world by population drive on the left, and 66% on the right. But this doesn’t answer why !!!

The first legal reference in Britain to an order for traffic to remain on the left occurred in 1756 with regard to London Bridge. The Highway Act 1773 contained a recommendation that horse traffic should remain on the left and this is enshrined in section 78 of the Highway Act 1835.

In the late 1700s, a shift from left to right took place in countries such as the United States, when teamsters started using large freight wagons pulled by several pairs of horses. The wagons had no driver’s seat, so the driver sat on the left rear horse and held his whip in his right hand. Seated on the left, the driver naturally preferred that other wagons overtake him on the left so that he could be sure to keep clear of the wheels of oncoming wagons. He did that by driving on the right side of the road.

The British, however, kept to the left. They had smaller wagons, and the driver sat on the wagon, usually on the right side of the front seat. From there he could use his long whip in his right hand without entangling it in the cargo behind him. In that position, on the right side of the wagon, the driver could judge the safety margin of overtaking traffic by keeping to the left side of the road. Countries that became part of the British Empire adopted the keep-left rule too, although there were some exceptions. Canada, for example, where the maritime provinces and Vancouver (later to become British Columbia) drove on the left, eventually changed to the right in order to make border crossings to and from the United States easier. Nova Scotia switched to driving on the right on 15 April 1923.

On most early motor vehicles, the driving seat was positioned centrally. Some car manufacturers later chose to place it near the centre of the road to help drivers see oncoming traffic, while others chose to put the driver's seat on the kerb side so that the drivers could avoid damage from walls, hedges, gutters and other obstacles. Eventually the former idea prevailed.

Friday, July 20, 2007

Nothing but blue sky ... and chemical

Every year, China launches thousands of rockets and artillery shells into the sky. They're not part of a set of war games or preparation for a battle with Taiwan, but rather a battle with the weather. Through its Weather Modification Program, the Chinese government hopes to control the fickle forces behind rain. Run by the Weather Modification Department, a division of the Chinese Academy of Meteorological Science, the program employs and trains 32,000 to 35,000 people across China, some of them farmers, who are paid $100 a month to handle anti-aircraft guns and rocket launchers.

The heavy weapons are used to launch pellets containing silver iodide into clouds. Silver iodide is thought to concentrate moisture and cause rain. The process is known as cloud seeding and China has invested heavily in it, using more than 12,000 anti-aircraft guns and rocket launchers in addition to about 30 planes

Chinese research into weather control began in 1958, when the practice was still in its early stages. With a population of more than 1.3 billion, China requires vast amounts of water. Cities like Beijing suffer from terrible smog, and rain can help clear away air pollution. The government is using cloud seeding to try to produce rain for farmers, stave off drought and fill water basins.

So how does it work? Even in areas with very low humidity, water is present in the sky and in clouds. A rainstorm happens after moisture collects around particles in the air, causing it to reach a level of saturation at which point it can no longer hold in that moisture. Cloud seeding essentially helps that process along, providing "nuclei" around which water condenses. These nuclei can be salts, calcium chloride, dry ice or silver iodide, which the Chinese use. Silver iodide is used because its form is similar to ice crystals. Calcium chloride is often used in warm or tropical areas.

The Chinese are not the first to use this technique.Noted atmospheric scientist Bernard Vonnegut (brother of novelist Kurt Vonnegut) is credited with discovering the potential of silver iodide for use in cloud seeding during 1946 while working for the General Electric Corporation in the state of New York. This property is related to a good match in lattice constant between the two types of crystal (the crystallography of ice later played a role in Kurt Vonnegut's novel Cat's Cradle). The first attempt at cloud seeding was in upstate New York during 1946. Vincent Schaefer, a General Electric chemist, caused snow to fall near Schenectady, NY after he dumped six pounds of dry ice into a cloud from a plane.

Silver iodide is mostly used for winter snowfall augmentation over mountains and hail suppression. While not a new technique hygroscopic seeding for enhancement of rainfall in warm clouds is enjoying a revival, based on some positive indications from research in South Africa, Mexico, and elsewhere. The hygroscopic material most commonly used is salt. It is postulated that hygroscopic seeding causes the droplet size spectrum in clouds to become more maritime (bigger drops) and less continental, stimulating rainfall through coalescence.

From March 1967 until July 1972, the US military Operation Popeye cloud seeded silver iodide to extend the monsoon season over North Vietnam, specifically the Ho Chi Minh Trail. The operation resulted in the targeted areas seeing an extension of the monsoon period an average of 30 to 45 days. The 54th Weather Reconnaissance Squadron carried out the operation to "make mud, not war."

One private organization which offered, during the 1970s, to conduct weather modification (cloud seeding from the ground using silver iodide flares) was Irving P. Crick and Associates of Palm Springs, California. They were contracted by the Oklahoma State University in 1972 to conduct such a seeding project to increase warm cloud rainfall in the Lake Carl Blackwell watershed. That lake was, at that time (1972-73), the primary water supply for Stillwater, Oklahoma and was dangerously low. The project did not operate for a long enough time to show statistically any change from natural variations. However, at the same time, seeding operations have been ongoing in California since 1948.

An attempt by the United States military to modify hurricanes in the Atlantic basin using cloud seeding in the 1960s was called Project Stormfury. Only a few hurricanes were tested with cloud seeding because of the strict rules that were set by the scientists of the project. It was unclear whether the project was successful; hurricanes appeared to change in structure slightly, but only temporarily. The fear that cloud seeding could potentially change the course or power of hurricanes and negatively affect people in the storm's path stopped the project.

Two Federal agencies have supported various weather modification research projects, which began in the early 1960s: The United States Bureau of Reclamation (Reclamation; Department of the Interior) and the National Oceanic and Atmospheric Administration (NOAA; Department of Commerce). Reclamation sponsored several cloud seeding research projects under the umbrella of Project Skywater from 1964-1988, and NOAA conducted the Atmospheric Modification Program from 1979-1993. The sponsored projects were carried out in several states and two countries (Thailand and Morocco), studying both winter and summer cloud seeding. More recently, Reclamation sponsored a small cooperative research program with six Western states called the Weather Damage Modification Program, from 2002-2006.

Funding for research has declined in the last two decades. A 2003 study by the United States National Academy of Sciences urges a national research program to clear up remaining questions about weather modification's efficacy and practice.

In Australia, CSIRO conducted major trials between 1947 and the early 1960s:

1947 – 1952: CSIRO scientists dropped dry ice into the tops of cumulus clouds. The method worked reliably with clouds that were very cold, producing rain that would not have otherwise fallen.
1953 – 1956: CSIRO carried out similar trials South Australia, Queensland and other States. Experiments used both ground-based and airborne silver iodide generators.
Late 1950s and early 1960s: Cloud seeding in the Snowy Mountains, on the Cape York Peninsula in Queensland, in the New England district of New South Wales, and in the Warragamba catchment area west of Sydney.
Only the trial conducted in the Snowy Mountains produced statistically significant rainfall increases over the entire experiment.

Thursday, July 19, 2007

The Secret Origin of Mr. Potato Head

Mr. Potato Head was the invention of George Lerner in the late 1940s. The idea was originally to have it be a prize in breakfast cereal so that the separate parts could be distributed as cereal package premiums. But later Lerner showed the idea to the textile manufacturers Henry and Merrill Hassenfeld, who did business as the Hassenfeld Brothers (later shortened to Hasbro). and they loved it,so they bought back the rights.


When the toy was first manufactured, it came with 30 accessories.
When it was first sold to the public in 1952 it became the first toy to be sold through national television advertising and netted Hasbro over USD$4 million in Mr. Potato Head sales in its first year of production. In 1953, Mrs. Potato Head was added, and soon after Brother Spud and Sister Yam completed the Potato Head family. Although originally produced as separate plastic parts to be stuck into a real potato or other vegetable, a plastic body was added to the kit in the late 1950's.

In 1973 the main potato part of the toy doubled in size and the size of its accessories were similarly increased. This was done mainly due to new toy child safety regulations that were introduced by the U.S. government. Hasbro also replaced the holes with flat slats, which made it impossible for users to put the face pieces and other body parts the wrong way around. In the 1980s Hasbro reduced their range of accessories for Mr. Potato Head to one set of parts. They did however reintroduce round holes in the main potato body, and once again parts were able to go onto the toy the wrong way around

I admit, this one was for me. I accidentally stumble upon this picture and I just had to show it to the world … just plain funny ;)

Wednesday, July 18, 2007

Fear of the Dark

The firefly use of bioluminescence to attract mates or prey. It's capable of producing a "cold light" containing no ultraviolet rays, with a wavelength from 510 to 670 nanometers, pale yellowish or reddish green in color, with a lighting efficiency of 96%.

Bioluminescence is a very efficient process. 90 per cent of the firefly's energy is converted into light. By comparison, an incandescent electric bulb can convert only 10 percent of total energy into light, and the remainder is emitted as heat.

Light production in fireflies is due to a chemical reaction that occurs in specialized light-emitting organs, usually on the lower abdomen. The enzyme luciferase acts on luciferin in this organ to stimulate light emission. This reaction is of scientific interest. Genes coding for these substances have been inserted into many different organisms (Mice, silkworms, and potatoes). Luciferase is also used in forensics, and the enzyme has medical uses.

Tropical fireflies, particularly in Southeast Asia (Thailand and Malaysia), routinely synchronize their flashes among large groups, a startling example of spontaneous biological order. This phenomenon occurs through the night along river banks in the Malaysian jungles every day of the year. Current hypotheses about the causes of this behavior involve diet, social interaction, and altitude. In the United States, one of the most famous sightings of fireflies blinking in unison occurs near Elkmont, Tennessee in the Great Smoky Mountains during the second week of June.

Tuesday, July 17, 2007

Easy as a, b, c

Can your name really affect your life? As contrived - or cruel - as the names Brooklyn, Romeo and Cruz might be, the happiness of the Beckham boys could be salvaged by their surname. Not, as you might think, because it's a famous name; if their father had been called David Wickham things could have been quite different.


A study revealed that people whose surnames began with letters at the beginning of the alphabet did indeed rate themselves as significantly more successful overall than those with surnames starting with lowly, end-of-the-alphabet initials.


The surname effect was especially pronounced when it came to career, suggesting that alphabetical discrimination was alive and well in the workplace. Interestingly, the effect was also more visible in men than in women. This may, of course, reflect the fact that many women change their surname when they marry. Perhaps women who are considering whether to adopt their husband's surname should take into account the alphabetical implications - or choose a real Alpha-male in the first place.What might account for this seemingly strange effect? One pattern in the data provided an important clue.


The surname effect became more pronounced in older age groups, suggesting that it was not due to childhood experiences, but rather that it built up gradually during our lives. It seems that constant exposure to being at the top or bottom of the alphabet league - the A-list or the Z-list - slowly makes an impact on the way in which people see themselves.
Again, as I reported before my surname investigation, past studies suggest that this is a real possibility.


In 1999, Nicholas Christenfeld and his colleagues from the University of California, San Diego, uncovered evidence suggesting that a person's initials might affect perhaps the most important aspect of their life - the moment of their death. Using a large, computerised database of death certificates, they identified people whose initials formed a positive-sounding word (such as A.C.E., H.U.G. and J.O.Y.), and those that had very negative connotations, like P.I.G., B.U.M. and D.I.E. Using factors such as race, year of death and socio-economic status as controls, the researchers discovered that men with positive initials lived approximately four and a half years longer than average, whereas those with negative initials died about three years early.
Women with positive initials lived an extra three years, although there was no detrimental effect for those with negative initials. Further analysis suggested that those with negative initials were especially likely to die from psychological causes, such as suicides and self-inflicted accidents.So should these results give those whose surname initial falls towards the end of the alphabet cause for concern? Well, as a Wiseman, and therefore someone with a lifetime's experience of coming towards the bottom of alphabetical lists, I take some comfort from the fact that the effect is very small. Then again, when you look at some of the best-known people around today - Blair, Brown, Bush, Cameron, Branson - it does make me wonder.

Monday, July 16, 2007

The Winepire Strike Back

A few days ago, we talked about how wine can be good for your teeth and breathe. I then wonder … is it the end of the Mouthwash or is it a sweet revenge of the wine industry?

You way wonder why I talk about “sweet revenge”. I’ll explain this in a bit, but let’s start with a bit of history. Anthony van Leeuwenhoek, the famous 17th century microscopist, discovered living organisms (living, because they were motile) in deposits on the teeth (what we now call dental plaque). He also found organisms in water from the canal next to his home in Delft. He experimented with samples by adding vinegar or brandy and found that this resulted in the immediate immobilization or killing of the organisms suspended in water. Next he tried rinsing the mouth of himself and somebody else with a rather foul mouth with vinegar or brandy and found that living organisms remained in the dental plaque. He concluded - correctly - that the mouthwash either did not reach, or was not present long enough, to kill the plaque organisms.

That remained the state of affairs until the late 1960s when Harald Loe (at the time a professor at the Royal Dental College in Aarhus, Denmark) demonstrated that a chlorhexidine compound could prevent the build-up of dental plaque. The reason for chlorhexidine effectiveness is that it strongly adheres to surfaces in the mouth and thus remains present in effective concentrations for many hours. Rinses in this category include Listerine and Scope.

Active ingredients in commercial brands of mouthwash can include thymol, eucalyptol, hexetidine, methyl salicylate, menthol, chlorhexidine gluconate, benzalkonium chloride, cetylpyridinium chloride, methylparaben, hydrogen peroxide, domiphen bromide and sometimes fluoride, enzymes and calcium. Ingredients also include water, sweeteners such as sorbitol and sodium saccharine, and a significant amount of alcohol (around 20%).

Now, I think that you can see where I’m going. Hobo’s have been known to drink mouthwash as a cheap alcohol replacement (I’m not sure that’s very healthy though). In a sense, mouthwash took away a part of the wine market. Now, it’s wine turn!!! In fact, because of the alcohol content, it is possible to fail a breathalyzer test after rinsing with mouthwash; in addition, alcohol is a drying agent and may worsen chronic bad breath.

Go Wine!!!!

Friday, July 13, 2007

Dancing in the Rain

Today's, I learned a new term: Rain Shadow. The principle is nothigh spectacular, but still, I learned something new.

A rain shadow is a dry region on the surface of the Earth that is leeward or behind of a mountain with respect to the prevailing wind direction. A rain shadow area is dry because, as moist air masses rise to the top of a mountain range or large mountain, the air cools and the maximum moisture content decreases until it reaches the dew point, where the water vapor condenses as rain or snow and falls on the windward side or top of the mountain. This process is called orographic precipitation. The effect of the process is the creation, on the leeward side, of an area of descending dry and warming air (see Foehn wind), and a region that is quite arid.

Thursday, July 12, 2007

May the force be with you

A couple of days ago, I was watching a movie when I start wondering why is there opening credits? My friend argued that it was an obligation by the Directors Guild of America (for American film or course). I then said ... what about Star wars ... and then it the silence came.

So I felt compelled to find the answer. In recent years, many major American motion pictures have done away with opening credits, with many films, such as Van Helsing, Batman Begins, and The Mummy Returns not even displaying the film title until the closing credits begin. George Lucas is credited (or blamed) with popularizing this with his Star Wars films which display only the film's title at the start. His decision to omit opening credits in his films Star Wars Episode IV: A New Hope (1977) and Star Wars Episode V: The Empire Strikes Back led him to resign from the Directors Guild of America. However, Hollywood had been releasing films without opening credits for many years before Lucas came along, most notably Citizen Kane and The Godfather. However, it was with the release of Lethal Weapon 2 in 1989 that the "title only" opening became an established form for summer blockbusters. Clint Eastwood has done away with opening credits (except for the title) in every film that he has directed since approximately 1982.

Wednesday, July 11, 2007

Coffee Facts

A cup of drip brewed coffee has about 115 milligrams of caffeine, an espresso (and percolated coffee) about 80mg, while instant coffee has about 65mg of caffeine. Decaffeinated coffee is not totally caffeine free, containing about 3mg of caffeine. A can of Coca-Cola has about 23mg of caffeine, Pepsi Cola 25mg, Mountain Dew 37mg, and TAB 31mg. Tea has about 40mg of caffeine, while an ounce of chocolate contains about 20mg.

The first Espresso machine was introduced in 1822 by the French, but it was the Italians who later perfected and distributed it.

Coffee is the world's most popular stimulant: 4 out of 5 Americans drink it, consuming more than 400 million cups a day. Consumption in Scandinavian countries is more than 12kg (26lb) per capita. With more than 25 million people employed in the industry, coffee is second only to oil in world trade.

The word "tip" is also related to coffee. It comes from old London coffeehouses where the waiters' brass boxes were etched with the inscription, "To Insure Promptness." In fact, it was in one such coffeehouses which belonged to a Mr Lloyd that a few cargo insurers got together to start the Lloyd's insurance company.

Tuesday, July 10, 2007

How to walk on water

Do you ever wonder why water drops have a spherical shape? Because a sphere has the smallest possible surface area to volume ratio. An which force required such ratio ? Surface Tension.


Surface tension is caused by the attraction between the molecules of the liquid by various intermolecular forces. In the bulk of the liquid each molecule is pulled equally in all directions by neighboring liquid molecules, resulting in a net force of zero. At the surface of the liquid, the molecules are pulled inwards by other molecules deeper inside the liquid but they are not attracted as intensely by the molecules in the neighbouring medium (be it vacuum, air or another liquid). Therefore all of the molecules at the surface are subject to an inward force of molecular attraction which can be balanced only by the resistance of the liquid to compression. Thus the liquid squeezes itself together until it has the locally lowest surface area possible.





The photograph shows water striders standing on the surface of a pond. It is clearly visible that its feet cause indentations in the water's surface. And it is intuitively evident that the surface with indentations has more surface area than a flat surface. If surface tension tends to minimize surface area, how is it that the water striders are increasing the surface area?
Recall that what nature really tries to minimize is potential energy. By increasing the surface area of the water, the water striders have increased the potential energy of that surface. But note also that the water striders' center of mass is lower than it would be if they were standing on a flat surface. So their potential energy is decreased. Indeed when you combine the two effects, the net potential energy is minimized. If the water striders depressed the surface any more, the increased surface energy would more than cancel the decreased energy of lowering the insects' center of mass. If they depressed the surface any less, their higher center of mass would more than cancel the reduction in surface energy.

Monday, July 9, 2007

Water Slide

I was looking for an article on surface tension when I felt onto theses facts:
Water is a common chemical substance that is essential to all known forms of life. In typical usage water refers only to its liquid form or state, but the substance also has the solid state, ice, and gaseous state, water vapor. About 1,460 teratonnes (Tt) of water cover 71% of Earth's surface, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds, and precipitation.[2] Saltwater oceans hold 97% of surface water, glaciers and polar ice caps 2.4%; and other land surface water such as rivers and lakes 0.025%. Now, you have to be impressed by theses numbers.

Tomorrow: Why can water stride walk on water?

Friday, July 6, 2007

My Two Cents

I’m sorry for yesterday’s absence, but I’m in some kind of rush at work. So today’s gonna be a quick one: Can a penny dropped from the top of a tall building kill a pedestrian?

A penny isn't the most aerodynamic of weapons. A combination of its shape and wind friction means that, tossed even from the 1,250-foot Empire State Building, it would travel fast enough merely to sting an unlucky pedestrian.

Wednesday, July 4, 2007

Brain Teasers

Today’s fact is about a popular misconception that human uses only 10% of our brain. This misconception arose from a misunderstanding of neurological research in the late 1800s or early 1900s when researchers either discovered that only about 10% of the neurons in the brain are firing at any given time. Another possible origin of the misconception is that only 10% of the cells in the brain are neurons; the rest are glial cells that, despite being involved in learning, do not function in the same way that neurons do. If all of a person's neurons began firing at once, that person would not become smarter, but would instead suffer a seizure. In fact, studies have shown that the brains of more intelligent people are less active than the brains of less intelligent people when working on the same problem (which does not in any way mean that epileptics are less intelligent).

Tuesday, July 3, 2007

Fly Me to the Moon


When low on the horizon, the Moon can appear to be larger than when it's higher in the sky. It's all an illusion, scientists say, and it does not involve any enlarging effects of the atmosphere. Rather, it's all in your mind.

Here's how it works: Our brains think things on the horizon are farther away than stuff overhead, because we're used to seeing overhead clouds that are close compared to those on the horizon. In the mind's eye, the sky is a flattened dome. With this dome as a reference, we expect something on the horizon (such as the moon) to be father, and because it is actually no farther than when overhead, our brains goof and imagine that it is larger.

Now, that what I call an all natural enlargement process ;)


Most of the articles on these pages are taken from different site. Since I tend to strip the article to only keep the essential, I don’t use quote because it would (to keep it simple). Link to the used resources are kept in the link section. If you want to know the sources for any particular article, just ask the question in the comment form.