Science & Nature – Page 9 – Jineral Knowledge

Tea

Posted on 27/11/201209/03/2019 by Jinavie

Among the many hot beverages the world enjoys, tea is probably the number one. No matter how many people drink coffee, no beverage has a history like tea. From the tea ceremony cultures of the East to the Boston Tea Party of the West, the history of tea is long and full of stories. As everyone knows, tea is a drink made by boiling down the leaves of a plant. There are many types of tea: black, oolong, green, yellow and white being the most common. Teas made from more aromatic plants such as jasmine and chamomile are typically put in a separate category known as herbal teas. One surprising fact about tea is that most of them are derived from the same plant.

The plant Camellia sinensis is the source of all teas, with the aforementioned black, oolong, green, yellow and white teas all coming from the leaves of this one plant. However, what makes each tea unique is the way the leaves are processed. For example, if you steam freshly picked leaves of the Camellia sinensis plant then dry them out, you make green tea. If you wither the leaves then lightly crush and bruise them to promote oxidisation, you make black tea. The different ways of processing tea leaves gives each type of tea a unique flavour due to a variety in the ratio of various chemicals. For example, black tea is rich in tannin because of oxidisation, whereas green and oolong teas are milder as they have higher levels of catechins than tannin (the oxidised product of catechin). As catechins act as antioxidants in the human body, green tea is effective in slowing the aging process.

Although the source of the leaves are the same, the different ways of processing makes each tea unique in their ways of preparation. The milder white, yellow and green teas are best prepared by steeping them in water heated to (or cooled from boiling) 70~80°C for 1~2 minutes, while oolong and black tea should be steeped for 2~3 minutes in near-boiling water (80~99°C) for the best taste.

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Banana Equivalent Dose

Posted on 27/10/201209/03/2019 by Jinavie

No form of energy has been more feared or creatively explored in science fiction (e.g. Godzilla) as radiation, yet the layman tends to know little about the actual properties and effects of radiation. The word “radiation” is commonly associated with things like Chernobyl, mutation and cancer. However, most people only know that radiation is “bad” while not knowing exactly how and why it is dangerous. Radiation is essentially high-frequency light which can deliver a large dose of energy (just like how microwaves cook food and sunlight can burn paper when focussed through a magnifying glass). When this high-dose of energy passes through living organisms, it damages the DNA in cells, potentially causing irreparable damage. This can lead to mutation and disruption of cell division (which can lead to cancer) or cell death (which is why radiation is ironically used to kill cancer cells).

The more technical question is “how much” radiation is harmful. For example, how much more dangerous was the Chernobyl incident compared to an x-ray? Like many other things in science, radiation is measured using an internationally universal unit called the Sievert (Sv). The radiation received from standing next to the Chernobyl reactor core after meltdown was 50Sv, while a chest x-ray is 20μSv (1000μSv = 1mSv, 1000mSv = 1Sv). Therefore, the Chernobyl incident could be considered to be as strong as 2.5 million chest x-rays. Although there is great variation, it is considered that a dose of 400mSv can cause symptoms of radiation poisoning, while 4~8Sv of radiation will lead to certain death.

Fascinatingly, radiation is not an uncommon thing. Radiation is all around us, with an average person receiving about 10μSv of background radiation per day just by living on Earth. Ergo, two days of walking around gives you the same amount of radiation as a single chest x-ray. A CT scan gives out a significantly greater dose of radiation at about 7mSv (approximately 350 x-rays or a year’s worth of background radiation).

However, the Sievert is a unit that is difficult to understand. Thus, some scientists devised a clever, humorous equivalent unit called the banana equivalent dose (BED). Bananas contain a certain amount of radioactive isotopes (radioactive potassium), making them technically radioactive. A banana contains 0.1μSv of radiation. Ergo, a chest x-ray is the equivalent to eating 200 bananas, a CT scan is 70000 bananas, while the Chernobyl incident gave people nearby a dose of roughly 500 million bananas.

The banana equivalent dose is a rather useful (and hilarious) way of comparing the danger of radiation from different sources. The next time you go to hospital for an x-ray, just picture 200 bananas being shot through your chest.

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Pi

Posted on 21/10/201209/03/2019 by Jinavie

Pi (π) a mathematical constant that is defined as the ratio of a circle’s circumference to its diameter. It is approximately equal to 3.14159, but since it is an irrational number (cannot be expressed as a ratio), the decimal places go on and on with no repeating segments. The history of pi extends back to almost 5000 years ago, as it plays such a crucial role in geometry, such as finding the area of a circle (A = π ²). It is not an understatement to say that pi is among the top five most important numbers discovered in history (0, 1, i and e being the others).

The interesting thing about pi is that it is an irrational number. As mentioned above, this means that pi has an infinite number of non-repeating decimal places, with numbers appearing in random sequence. For example, pi to a 30 decimal places is 3.141592653589793238462643383279… Because of this feature, pi contains all possible sequences and combinations of numbers at a certain point. The corollary to this fact is, if pi is converted into binary code (a number system of only 0 and 1, used by computers to encode information), somewhere in that infinite string of digits is every combination of digits, letters and symbols imaginable. The name of every person you will ever love. The date, time and manner of your death. Answers to all the great questions of the universe. All of this is encoded in one letter: π.

That, is the power of infinity.

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Units

Posted on 21/09/201209/03/2019 by Jinavie

In September of 1999, NASA ambitiously launched a Mars weather satellite. But the satellite did not even reach its destination, instead exploding in the atmosphere soon after launch. Why was this? The reason was so stupidly simple. The failure was because of units.

The satellite that was designed by Lockheed Martin was designed using the imperial system (pounds, feet and yards), whereas NASA’s systems used the internationally-used metric system. Because of this simple error, the pride of the USA space program fell to the ground and an astronomical amount of money was burnt to ashes in the air.

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Mathematical Beauty

Posted on 15/09/201209/03/2019 by Jinavie

What is the most “beautiful” mathematical equation? For millenia, many mathematical formulas and concepts have been described as beautiful (and some defining beauty, as the golden ratio does). In the mathematical world, the adjective “beautiful” is used in the sense that certain mathematical concepts, despite the fact they are rational and objective, are so pure, simple and elegant that they can only be described as art.

One such formula is Euler’s identity:

Renowned physicist Richard Feynman described it as “the most remarkable formula in mathematics”. What makes this array of symbols and numbers so beautiful? Firstly, it contains the three basic arithmetic operations exactly once each: addition, multiplication and exponentiation. It also connects five fundamental mathematical constants with nothing other than themselves and the arithmetic operations.

0 is the additive identity, as adding it to another number results in the original number. 1 is the multiplicative identity for the same reason as 0. Pi(π) is one of the most important mathematical constants in the history of mathematics that is ubiquitous in Euclidean geometry and trigonometry. Euler’s number(e) is the base of natural logarithms and is used widely in mathematical and scientific analysis. i(√-1) is the imaginary unit of complex numbers, a field of imaginary numbers that are not “real”, allowing for the calculation of all roots of polynomials. Euler’s identity neatly sums up the relation between these five numbers that are so crucial in the field of mathematics. It is also interesting to note that these five numbers were discovered at different points in history spanning over 3000 years.

Some people describe mathematics as a distinct language in itself. Not only that, but mathematics is considered the universal language as it is both universal and ubiquitous. If that is the case, than Euler’s identity can be considered an extremely pithy literary masterpiece.

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Wave

Posted on 08/09/201209/03/2019 by Jinavie

One of the joys of going to a beach is listening to the breaking of waves. Waves are typically associated with the ocean, but can also form on lakes, rivers, canals or any body of water with a free surface.

Waves are caused by wind blowing over the water surface, dragging it in a certain direction. As the wind only affects the surface, the water below rises to fill the space, causing a circular movement. This appears as a wave on the surface. The faster the wind blows, the more the surface is shifted and the bigger the waves become. Other factors that determine the wave size are: water depth, distance of water that the wind blows over (fetch), the width of the area of the fetch and the duration the wind blows over the area. Because of these factors, some lakes may be as wavy as the sea while others are completely tepid.

The waves formed by the wind merge to form bigger waves in the ocean. The resulting wave is known as a swell. When the swell reaches the shore, the depth of the water reduces, causing the wave to rise in height and become steeper. If the wave is high enough, the base becomes unstable and the wave collapses, which is what causes waves to break.

Although it sounds like a simple process, the consequences can be deadly. Wind waves can reach heights above 30m given that the conditions are right (usually during extremely serious storms). Such a wave can flip a cruise ship with ease like a rubber toy.

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Dihydrogen Monoxide

Posted on 01/09/201209/03/2019 by Jinavie

Many people know about the dangers of chemicals such as lead and dioxin, but there is lack of awareness of an even bigger killed chemical: dihydrogen monoxide. It is a colourless, odourless, tasteless chemical that is responsible for the death of hundreds of thousands of people around the world.

Most deaths caused by dihydrogen monoxide (DHMO) are by accidental inhalation, causing cerebral hypoxia. However, the dangers of DHMO do not end there. Its solid form can cause severe tissue damage after prolonged exposure, and both its gas and liquid forms can cause severe burns. It is possible to overdose on DHMO, with symptoms ranging from excessive diaphoresis and micturition, bloating, nausea, vomiting and body electrolyte imbalance such as hyponatraemia. For those who are dependent on it, withdrawal means certain death. DHMO has also been found in various types of tumours biopsied from terminal cancer patients.

Not only does DHMO have consequences on human health, it is also damaging for the environment. DHMO is the leading cause of the greenhouse effect (surpassing carbon dioxide), a key component of acid rain, accelerated corrosion and rusting of many metals and contributes to the erosion of natural landscapes. DHMO contamination is a real, global issue, with DHMO being detected in lakes, streams and reservoirs across the globe. DHMO has caused trillions of dollars of property damage in almost every country, especially in developing nations.

Despite the danger, DHMO is commonly found in the household, in the form of additives in food and drinks, cleaning products and even styrofoam. There are no regulation laws for DHMO and multi-national companies continue to dump waste DHMO into rivers and the ocean. It is astounding to see such a deadly chemical go unregulated.

If you have not caught on by now, dihydrogen monoxide’s chemical formula is H2O – also known as water. Technically speaking, there are no false statements in the above description. But even children know that water is not only (relatively) safe, but necessary for life. The report on “dihydrogen monoxide” originates from a 1997 science fair project by Nathan Zohner, who was 14 years old at the time. His project was titled “How Gullible Are We?” and involved presenting his report about “the dangers of DHMO” to fifty school students to see what their reaction would be. 43 students favoured banning it, 6 were undecided and only one recognised that DHMO was actually water. Even more surprising is that there are cases (such as in California in 2004), where city officials came close to banning the substance, falling for the hoax. This goes to show how gullible people can be in the face of what they do not know.

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Vision

Posted on 14/08/201209/03/2019 by Jinavie

Consider this: if you see something that is not there, or not see something correctly, is that due to a problem in your eyes or your brain? An interesting anatomical fact is that the eyes are part of the brain. They originally evolved from the brain and drifted further and further forwards, connected to the brain by the optic nerves. If you lift a brain out from the skull, the eyes would be pulled backwards too. But technically speaking, eyes are distinct organs by themselves that have merely originated from a portion of the brain. It does not think or make decisions by itself. Just like a camera, an eye records things as it sees it and transmits it to the brain via the optic nerve via electrical signals. The brain then processes the signals in the occipital lobe, located at the back of the head (this is why you “see stars” when you bang the back of your head).

This means that vision can be altered anywhere along the pathway. If you have cataracts, where the lens of the eye becomes clouded, you lose portions of your visual field. If you have a large pituitary gland tumour, it presses on the optic nerve and causes double vision (diplopia) or vision loss. If you have a stroke in the occipital lobe, you can lose your vision. The brain’s role in producing vision can easily be demonstrated in the form of optical illusions. The eye merely records and transmits what it sees, but the brain becomes confused by what information it receives and tries to make sense of it. In the process, we experience bizarre illusions such as static images moving by themselves.

Because of this intricate pathway, some pathologies present with fascinating symptoms. A condition called Anton’s blindness (or Anton-Babinski syndrome) causes a patient to “see” despite being blind. Patients with Anton’s blindness are adamant that they can see perfectly clearly, and will even describe what they are seeing. However, what they “see” is completely different to what the object actually looks like. For example, if the patient looked at a blonde woman wearing a yellow blouse and a red skirt, they may describe her as a brunette woman wearing a blue shirt and black jeans.

The reason for their blindness is that their occipital lobe was damaged (usually by a stroke), leading to an inability to process the information from the eyes. Although the eyes are pristine and record what they see in perfect detail, the brain is incapable of interpreting the signals. The brain then goes on to confabulate, where the brain fills the gap by conjuring up false information. This makes Anton’s blindness quite hard to pick up on as the patient will not complain of it. It is only found when someone pays close attention to the patient and notices subtle cues like the patient bumping into furniture or talking in the direction where they think a person is at (even after they move). Ergo, the patient adamantly believes that they can see as their brain thinks it is seeing things (even though it is not receiving the information from the eyes properly).

Seeing is not believing. You see what you believe.

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Virgin Birth

Posted on 08/08/201209/03/2019 by Jinavie

Although the concept of virgin birth (i.e. conception without intercourse) is common in many religions, there is no conclusive evidence of actual human virgin birth in recorded history. Except in one medical article written in 1874 by a Dr Capers.

In this article, Dr Capers describes a case study of a miraculous conception during the Battle of Raymond during the US Civil War. A soldier was shot in the testicles and the musket ball carried the non-musket ball (read: testicle) into the uterus of a girl working in a nearby field. The doctor attended to the girl who was shot and treated the wound in her abdomen. The bullet was not found.

Over the following nine months, the doctor realised the girl was pregnant, although she claimed to be a virgin. After nine months, a healthy boy was born. Stranger yet, the doctor realised the boy’s scrotum was unusually swollen and upon examination, found that he was carrying the musket ball that impregnated the girl in the first place. He thus concluded that the testicle that was carried by the musket ball was lodged inside her uterus and sperm leaked out. The soldier was eventually found and was told about this bizarre story and the two were married.

This case study has become a famous story told by doctors around the world. Unfortunately, it is completely false and the doctor who wrote the article admitted to faking it to amuse himself. Ergo, there are still no recorded cases of a virgin birth in humans.

The closest to a virgin birth that was recorded is a case study of a young woman who was performing oral sex on a man. She was found by her boyfriend during the act and the boyfriend stabbed her and her lover with a knife. The knife injured her oesophagus, causing the sperm in it to track down the abdomen and down to her reproductive organs. By a stroke of luck, an egg was misplaced during ovulation, causing it to drift into the abdomen instead of the fallopian tube (ectopic pregnancy), and met with the sperm. The egg was then fertilised and the girl presented to the hospital three months later with excruciating abdominal pain. The ectopic fetus was removed.

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Honeybee Dance

Posted on 22/07/201209/03/2019 by Jinavie

How do honeybees share the location of a food source, such as a flower, to other bees of their colony? An Austrian biologist named Karl Von Frisch devised an experiment to learn how the honeybees communicated with each other. He set up two different food sources and tagged every bee that came to pot A green and bees that came to pot B red. He then studied the behaviour of these bees back at the hive. What he discovered was fascinating.

For millennia, beekeepers have noticed that some honeybees have a tendency of moving in a peculiar yet methodical way once they returned to their hive after foraging for flowers. The bees would move in a straight line while waggling their bottom (moving side-to-side), then walk in a semicircle back to where they started. They would then waggle in the same direction, then move in a semicircle on the opposite side, completing a figure-eight path. This is called a waggle dance.

Frisch noticed that bees with green spots and the bees with red spots both did the waggle dance once they returned to the hive, but in different directions. All bees with green spots danced so that the straight line pointed a certain direction, while the bees with red spots danced the same dance except pointing another direction. Amazingly, the angle between these two directions was exactly the same as the angle separating pot A and B (with the hive as a point of origin). Frisch deduced that the waggle dance was the language of honeybees.

Through further experimentation, Frisch was able to tease out the details of this “language”.

Honeybees’ eyes can see ultraviolet and polarised light, which allows them to see where the sun is in the sky at all times. This is because sunlight polarises so that it points towards the sun and honeybees can see this direction. Therefore, the bee’s eyes act as a solar compass that tracks the exact location of the sun in real-time.
Bees have a finely-tuned internal clock that allows them to predict exactly where the sun should be depending on time, season and latitude, as the sun moves through the sky.
Another point of reference that is used in the bees’ language is gravity. Gravity is a constant that does not change, meaning all bees know which direction is “up” and which is “down”. This also means they can use a vertical, perpendicular line as a standard zero-point.

By pairing the two global constants, gravity and the location of the sun, the bees can accurately signal to other bees the direction they should fly in to find the food source. If a bee does a waggle dance that points 60° right from the vertical “up” direction (as defined by gravity), it signals that the bees should fly 60° right from the direction of the sun. If the angle is 0°, the bees should fly directly towards the sun, and if the angle is 180°, the bees should fly directly away from the sun. The bees use their internal clock to calibrate the direction depending on the time of the day.

The straight line “waggle” part of the dance gives the information of distance. The longer the duration of the straight line, the further away the flower is. As a general rule of thumb, the duration of the straight line increases by 1 second for every 1 kilometre. When the food is within about 60m of the hive, the 8-shape waggle dance turns into an O-shape round dance. The bee deduces the distance by the energy required to fly to the location.

By encoding the two variables “direction” and “distance”, a bee can effectively use the waggle dance to accurately pinpoint the location of a food source. It is amazing to see that animals that we consider “primitive” such as bees have such an intricate method of communication.