Tag: science

Posted in Science & Nature

Turing Test

Posted on by Jinavie

Alan Turing was a brilliant British mathematician who was pivotal in cracking the German Enigma cipher using a complex computing machine. He was highly influential in the founding of computing science. One of his greatest areas of interest was artificial intelligence. Like other computer scientists of the time, Turing predicted that machine intelligence was possible in the future with rapid development of computers. On this topic, he proposed the following question: at what point is a machine truly “intelligent”?

Intelligence is too complicated to define neatly in a single line. Therefore, here is a simpler question: can a machine do what we can do? For this, he proposed a thought experiment based on a party game known as the imitation game. In the imitation game, a man and a woman go into separate rooms. Guests then try to tell who is a man and who is a woman by writing a series of questions, slipping it under the door, then receiving a typewritten answer. If the guests cannot tell the two apart, the two win the game.

Turing modified this game into what is now known as the Turing test. He proposed replacing one person with a machine. A person and a computer are placed in separate rooms and are asked the same question by a judge. They then give a typed response. If the judge cannot confidently tell who is human and who is not, then the machine passes the Turing test.

Of course, the Turing test was not designed as a formal assessment and is merely a thought experiment. It has plenty of weaknesses, such as the fact that it only tests whether the machine is acting “like a human” rather than “intelligently”. For example, some computers have passed the Turing test by intentionally making typos to mimic human behaviour. Some have argued that machines that pass the Turing test do not truly exhibit intelligence, as it is impossible to tell if they fully understand the language or whether they are just running algorithms on symbols that the machine does not understand.

Regardless, the Turing test opens the door on the exciting yet frightening world of artificial intelligence and what the future holds for humanity.

Turing Test

(Image source: http://xkcd.com/329/)

Posted in Science & Nature

Dust Explosion

Posted on by Jinavie

When we hear explosives, we commonly think of chemicals such as nitroglycerin or gunpowder. But an explosion is essentially just a rapid release of energy and expansion of gases due to combustion. This means that if something is combustible – that is, it can burn – it has the ability to explode. However, certain conditions have to be met so that the combustion can be sudden and rapid.

Because of this principle, it is possible to explode dust or other powdered substances. If the dust is combustible (such as flour or coal), suspended in the air at enough concentration in a confined space, with sufficient oxygen and an ignition source, a dust explosion can occur. For example, coal dust explosions are a common threat to miners and there have been countless incidents where mills and factories have exploded with great fury due to a dust cloud forming from grain, flour, powdered milk and sawdust etcetera.

The reason why dust will explode in such a condition but not when it a pile of dust is lit with fire is that in a dust cloud, every dust particle is in contact with air. This massively increases the surface area of the dust relative to its mass, meaning there more reactions can occur. In this case, the reaction is oxidisation of the substance, leading to combustion. This is why the finer the dust or powder, the greater the risk of an explosion. Even substances such as wood or aluminium can create an explosion when finely powdered enough.

The greatest casualty due to a dust explosion was in 1942 when a coal dust explosion in a Chinese mine killed 1549 miners. Another famous case was in 1878 when the Washburn “A” Mill in Minneapolis exploded, leading to the destruction of the world’s largest grain mill and five other mills. This reduced the city’s grain production to almost one-half.

Posted in Science & Nature

Voyager

Posted on by Jinavie

In 1977, NASA launched into space two unmanned probes named Voyager 1 and 2 respectively. These probes were designed to study Jupiter and Saturn and were not expected to function past this point. The original Voyager mission officially ended in 1989 when Voyager 2 did a close flyby of Neptune. However, as of 2014, both Voyagers are still travelling ever onward into interstellar space, sending back crucial data about our solar system and what is inside it, along with beautiful photographs of the planets.

The two Voyager probes greatly outlived their expected lifespan and exceeded what they were expected to do. Thanks to the Voyager program, we now have a far better understanding of our own Solar System, such as the fact that it is asymmetrical, or that Neptune had three rings. Voyager 1 is now the most distant man-made object from Earth – with its closest neighbour, Voyager 2, being billions of kilometres away from it. Yet it continues to strive onwards into the unknown, exploring the depths of space all alone.

The Voyagers also carry a golden record on which scientists recorded pictures, sounds and music (such as Bach and Mozart) that represented scenery found on Earth. It also includes various languages, mathematic formulas, a representation of our Solar System and our DNA, anatomy and reproduction. It is meant to be a time capsule of Earth, for our future descendants or whatever else may be out there.

Posted in Science & Nature

Silver

Posted on by Jinavie

Historically, silver has been associated with cleansing, healing, the moon and warding off evil. For example, it is said that some monsters such as werewolves would only die if it is shot by a silver bullet. The Greek goddess of hunting and the moon, Artemis, carries a silver bow. Although it is always seconded to gold when it comes to precious metals, silver is a fascinating metal.

It is the most reflective metal on Earth and has the highest conductivity for heat and electricity. It is ductile and malleable, making it a good choice of metal for making coins, jewellery and silverware (hence the name). Because of how reflective it is, it is also used in solar panels and special mirrors, such as those in telescopes.

Another useful characteristic of silver is its chemical reactivity. Thanks to this property, silver forms many different compounds with varying applications. Silver halides are photosensitive and turn dark when they are exposed to light. This is the basis of film photography, where the light shone on a film coated with silver halides leaves a photographic imprint. Silver oxides are sometimes used in batteries and silver/mercury alloys are used for dental fillings.

Silver also plays a role in medicine. Silver ions have been shown to inactivate bacteria such as E. coli, making silver nanoparticles a useful antiseptic that can be impregnated into different materials such as wound dressings. Silver nitrate sticks are used in emergency departments as applying it to a bleeding vessel in the nose will release nitric acid, which cauterises (burns off) the vessel to stop a nosebleed. In medieval Korea, silver spoons were used to test if a food has been poisoned with arsenic, as arsenic reacts with silver to form a black tarnish. If a person has too much silver build-up in their body, they can develop argyria (silver poisoning), which turns the skin an eerie bluish-grey colour.

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Posted in Science & Nature

Head Bobbing

Posted on by Jinavie

If you take the time to look at how most birds walk, such as a chicken or a pigeon, you will notice that they bob their heads. This seems extremely impractical as if we bobbed our heads like that, we would likely become dizzy and vomit quite soon. So why do birds do it and why does it not make them dizzy?

A major difference between birds and human beings is the way our vision works. In humans, our eyes are constantly moving at a rapid rate (saccade) to collate information and stabilise images. Even when we are walking and our head is moving around, our eyes use various sensory information and reflexes to fix our vision at one point, giving us a clear picture. This is such a powerful reflex that one test to check a person’s brainstem function (for example, when they are in a coma) is to move the head and see if the eyes stay fixed on a point or if they follow the head (doll’s eye test). If the brainstem is intact, the eyes will keep looking at a fixed point despite head movement.

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Birds on the other hand, cannot fix their vision this way. Instead what they do is they keep their head absolutely still in three-dimensional space when their body is moving. If you hold a chicken in the air and move the body around, you will find that the head stays stationary. This means that when they are walking, the bird’s head will stay still while the body takes a step forwards, then it will move to catch up to the body. From a third person’s point of view, this makes it look like they are bobbing their head, although they are just keeping it very still. In 1978, Dr Barrie J. Frost did an experiment where he put pigeons on a treadmill surrounded by a still backdrop and found that the pigeons did not bob their heads because there was nothing to see.

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Posted in Science & Nature

Mandrake

Posted on by Jinavie

The plant Mandragora officinarum, more commonly known as mandrake, is a plant that has interested people in various fields throughout history. Firstly, the root is split into two at the end, giving the uprooted plant the appearance of a human being. Secondly, it belongs to the nightshade family, containing plants such as the infamous deadly nightshade (belladonna), tobacco, Datura, petunia, tomatoes and potatoes. Like its relatives the belladonna and Datura, mandrakes contain alkaloids such as atropine, scopolamine and hyoscyamine. These substances are potent (and toxic) hallucinogenics and sedatives, which is why they have had various uses ranging from witchcraft to anaesthesia to murder through poisonings.

The shape of the mandrake and its hallucinogenic effects have given it notoriety. Legend goes that when a mandrake root is dug up, it shrieks with such terror that anyone who hears it will die – possibly referring to the toxicity of the alkaloids. Historical texts give detailed instructions on digging up mandrakes by tying a hungry dog to the root and making it pull the plant out of the ground when the owner is out of earshot and he lures the dog with food.

Other folklore suggest that mandrake only grow when the ground is inseminated by semen dripping from a hanged man. This folklore is likely fuelled by the mandrake’s human-like appearance. Ancient and medieval literature associates mandrake being used to make fertility agents and love potions(again, likely related to the hallucinatory, sedative effects). Mandrake is a common ingredient in magic rituals of various kinds, such as in Wiccan rituals.

Alkaloids extracted from mandrake have been used in medicine since the Middle Ages, where extracts were used to anaesthetise patients before surgery, as it has a sedating, hypnotic effect. Eye drops made from mandrake extract were used for hallucinations and mandrake syrups were used to aide sleep. In modern medicine, scopolamine is used in motion sickness patches and atropine is used to speed up the heart rate when it slows too much.

The extensive list of supposed and actual properties of mandrake has made it a popular plant in fiction as well and it can be found in countless works throughout time, such as works of Shakespeare, Sir Arthur Conan Doyle and J.K. Rowling.

Posted in Psychology & Medicine

Masculinity

Posted on by Jinavie

In the womb, a fetus with XY chromosomes is exposed to testosterone and other androgens that help it develop into a male. Research has shown that people exhibit features that give away how much testosterone we were exposed to before birth. The digit ratio is the ratio between the length of the second and fourth fingers. If both fingers are the same length, the ratio is 1. The lower the digit ratio (ring finger longer than index finger), the more testosterone the fetus was likely exposed to.

It is not clear why testosterone affects the length of your fingers, but there is significant evidence to support the theory. Men with a lower digit ratio tend to be described as more aggressive, dominant and overall “masculine”. Men with a higher digit ratio, closer to 1, are typically described to have more feminine traits such as higher emotional quotient, sensitivity and interestingly, excelling in mathematics and science. The effect is more pronounced in men but also affects women. Women with a low digit ratio are more likely to be assertive. It has also been shown that lesbian women have a lower digit ratio than heterosexual women.

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Posted in Science & Nature

Milk Tea

Posted on by Jinavie

In many cultures, it is normal to drink black tea with milk (and sugar, depending on preference). The milk neutralises the acidity of tea and softens the bitterness of tannins, making the tea more palatable and easier on the stomach. This is especially for strong teas such as Assam tea. However, the downside is that there is some evidence that adding milk to tea reduces the beneficial effects from drinking tea, such as relaxing blood vessels and reducing risk of heart disease.

One of the timeless debates is whether to pour the tea or milk first when mixing the two. It is such a bitter topic that there are even recordings in literature of people using the phrase “rather milk in first” as an insult to another person.

George Orwell once published an article on making a perfect cup of tea and he claimed that adding milk to tea allowed you to regulate the amount of milk as you stir. Tea-first advocates also insist that pouring the tea first allows for more brewing time and increases the flavour of the tea.

The reason for milk-first is more scientific. In the early days of tea-drinking, most households did not own high-quality porcelain teacups. Cheap porcelain teacups were too thin to withstand the hot temperature of fresh tea and would crack. Pouring milk first cooled the tea and stopped this from happening. Therefore, pouring tea first was seen as a show of social status as you could afford high-quality teacups. The other main rationale for adding milk first is that the hot tea denatures proteins in milk, which can reduce the flavour and creamy texture of the milk.

To settle this old argument, British chemist Dr Andrew Stapley of the Royal Society of Chemistry undertook experiments to determine which is better from a scientific point of view. He concluded that it is indeed better to pour milk first then add tea. The reasoning is that when you add milk to tea, individual drops contact the tea and increases the surface area exposed to hot tea, denaturing more proteins. Ergo, adding tea to milk reduces this process and provides for a richer, creamier flavour.

At the end of the day, it really is just a cup of tea and you should drink it in whatever way you desire.

Posted in Science & Nature

Space Pen

Posted on by Jinavie

According to a popular legend, it is said that during the height of the Space Race, NASA was hard at work trying to develop a pen that could be used in space. The standard ball-point pen relies on gravity to pull the ink to towards the ball, allowing it to write. Obviously, this design does not work in space. NASA reportedly spent $1.5 million (some sources say $12 billion) and finally developed a space pen. This pen could write upside-down or in zero-gravity, on almost any surface and would work even at temperatures below freezing or over 300°C.
The Russians were faced with the same dilemma – they used a pencil.

As entertaining the story of overthinking Americans is, it is a complete urban myth. Both US and Russian astronauts used pencils in the early stages of the Space Race, but there were many flaws with pencils. Firstly, it was deemed unsafe to write important official documents using an erasable writing tool. Secondly, wood is combustible and fire is potentially disastrous on a space mission. Lastly and most importantly, pencil lead is made of graphite and broken tips and graphite dust are commonly released when using a pencil. Graphite is an extremely conductive material and if the dust were to go into an electrical circuit, it could easily cause a short-circuit and spark a fire.

To solve this solution, Paul C. Fisher – founder of Fisher Pen Co. – invested his own funds (not the US government’s) to create a pen that used pressure-loaded ink cartridges, making it perfect for zero-gravity use. NASA approved of the pen’s effectiveness and not long after, even Russia imported about a hundred of these space pens for their own use.

Posted in History & Literature

Sweat Like A Pig

Posted on by Jinavie

The English idiom to describe profuse sweating is sweating like a pig. However, pigs lack the ability to sweat properly due to ineffective sweat glands, which is why they roll in mud to cool their bodies. The idiom is not wrong though, as it is not referring to the animal, but pig iron.

When refining iron, the iron ore is smelted in a furnace until it is liquid. As the liquid metal is extremely hot, it is poured into a mould where it can cool. The iron was set in a branching mould that apparently resemble many piglets suckling from a mother sow – hence the name: pig iron.

Back in the old days when technology was not as advanced, it was difficult to tell when the pig iron was cool enough to transport safely. This is where science came in handy. As the metal cools, the surrounding air reaches a dew point, causing droplets of water to form on the pig iron as condensation. The condensation made it look like the pig iron was “sweating”, hence the idiom. When the pig iron sweats, it is a sign that is cool enough to be moved safely without spilling and burning everything around it.