Science & Nature – Page 17 – Jineral Knowledge

Caffeine

Posted on 15/06/201112/02/2019 by Jinavie

Coffee is a magical drink that can make a busy person’s morning. Coffee’s stimulant effect is due to the substance called caffeine. Caffeine can make the mind more alert and drives away sleepiness for about 3~4 hours. This is why students studying for an exam or people working late love to drink coffee.
There are many students who say they do not like coffee and drink energy drinks instead. These drinks tend to advertise that the substances guarana and taurine give energy, but an interesting fact is that guarana is just a plant where caffeine is extracted from. Taurine has many beneficial actions in the body, but has no effect as a stimulant. Therefore, an energy drink is simply made of caffeine and sugar and holds no advantage over coffee.

Although caffeine is beneficial in moderate amounts, excessive consumption leads to adverse effects. A normal adult can handle up to about 400mg of caffeine. Any more and they could suffer from anxiety, insomnia, headaches, dehydration, increased urination, fever, rising heart rate, stomach pain, nausea and many other symptoms. As everyone’s rate of caffeine metabolism is different, only they know how much caffeine they can consume. Furthermore, the more coffee or tea you drink, you build a tolerance towards caffeine and can consume much more without adverse effects.

The following is a list of the caffeine content in common drinks and foods:

Drip coffee(200ml): 150mg
Espresso(50ml): 100mg (this is because the cups are small, the concentration is about 3 times that of drip coffee)
Caffeine tablet: 100mg
Energy drink(250ml): 80mg
Coca-cola(600ml): 60mg
Chocolate(250g): 60mg
Black tea(170ml): 50mg
Green tea(170ml): 30mg
Decaffeinated coffee(200ml): 10mg

However, the best method to drive away sleepiness is by sleeping. If you are tired, the only way to recover is by taking a 30 minute to 2 hour nap, especially if you will be driving or have a night shift.

Science & Nature

Titanic

Posted on 12/06/201114/10/2020 by Jinavie

Titanic is a film telling the story of the sinking of the eponymous ship, the RMS Titanic, directed by James Cameron in 1997. Most people are entranced by Leonardo DiCaprio and Kate Winslet’s excellent acting, the cutting-edge special effects and the waves of emotions that it projects to the audience, but there is another component that is just as amazing.
Most films and television shows tend to sacrifice science in the name of drama. Thus, science fiction movies are ironically quite inaccurate in even the most basic scientific facts. However, Titanic is strangely true to science despite being a drama film.

To start with, we can take the scene where Rose, embraced by Jack from behind, spreads her arms wide open like wings while on top of the stern of the Titanic. Here, Rose is seen standing so high that she is above the rails from the thighs up. In this position, even a slight push would cause her to lose balance and make her fall, causing the movie to end prematurely. But on closer inspection, it can be seen how Jack has his arms wrapping under the cables. To be so attentive to detail even in the moment of heated passion – Jack is surely a calm, cool-headed man.
In the scene where the Titanic is sailing, it takes 25 seconds for the ship to completely pass a point. Considering that the ship was 269m in length, this comes to a cruising speed of 38km per hour. This is 21 knots when converted – almost identical to the actual cruising speed of the Titanic which was 22 knots.

The movie is accurate in even finer details. Let us study the climactic scene of the sinking. When the ship is tilting at its highest point, a person took 4.3 seconds to fall and hit the water. This equates to a height of 91m, which can be achieved by a 269m ship tilting at about 40 degrees.
When Jack is bound by handcuffs, Rose bravely cuts the chain with an axe. But can a fair 18-year old girl summon such strength? If the chain is the thickness of two 5mm diameter metal rings, then the blade requires 49 Joules of energy to cut the chain. To achieve this, a 3kg axe must be swung at the speed of 20km/h, which is the same as dropping the axe from a height of 1.6m. Ergo, Rose can create enough energy simply by adding a little more strength to the axe as she swings it down from above her head.
Lastly, in the tragic scene where Jack sinks away, he disappears in 6.4 seconds. If by a rough estimate he sank about 2m, then it suggests that he descended at about 1/100 strength of free falling. This means Jack’s body density is about 1% greater than sea water. As the density of sea water is 1.04g per 1cm3, this is perfectly reasonable assuming that Jack is big-boned.

A film focussing on such fine scientific detail can certainly be called a masterpiece of the century. If only Rose’s voice did not echo in the final scene…

Science & Nature

Forecast

Posted on 02/06/201129/07/2024 by Jinavie

When the weather forecast says today will be sunny, it always seems to rain (and vice versa). In fact, according to a US study, forecasts are sometimes less accurate than flipping a coin. If not even professionals can accurately predict the weather, can ordinary people like you and I do it?
The key to this is observation. By carefully studying your surroundings, you can look in to the future.

There are many signs before rain comes. For example, if the sunset is unusually clear or if a mountain far away looks smaller or hazy then it is very likely that it will rain the next day. If you see a rainbow in the morning it suggests rain is coming from the west. On hot days without any wind, it is likely there will be a heavy shower.
Animals are also adept at telling the weather. Frogs crying, worms coming out and swallows flying low are all signs that the air is humid and rain is coming. Swallows are especially accurate, as they fly low to catch insects that cannot fly high due to the humidity weighing them down.
If you are at the beach and there is a swarm of jellyfish, avoid going out to sea. Jellyfish near the coastline is a premonition for a storm.

If a more accurate weather prediction is required, the most precise method is cloud observation. If you study them carefully they comprise three tiers, with some clouds rising vertically.

Clouds in the highest level

Cirrus: Very fine, white feathery clouds that almost look combed over. If these clouds are curvy and organised the weather will be fine, but if they appear banded or spread chaotically they can gather and form rainclouds and start a shower.
Cirrostratus: Looks like a veil of cotton curtaining the sky. They cause halos around the sun and moon, which is a sign of imminent rain.
Cirrocumulus: Looks like a spread of seashells on a beach. If you find these clouds over a beach in winter, it will rain soon.

Clouds in the middle level

Altocumulus: Either appears as an ordered stream of rounded clouds, or looks like a herd of sheep. If these clouds shrink in size, the weather gets better (and vice versa).
Altostratus: Shaped like streaks of veil across the sky. They are often light grey or very dark. If they become thicker or sink to a lower level, it is a sign that the weather will be cloudy with a chance of rain.
Nimbostratus: The common “raincloud”, bringing rain and snow.

Clouds in the lowest level

Stratocumulus: Clumps of clouds that appear in layers without clear boundaries. You can see clear sky through gaps between them. If you can see clouds that were cumulus in the afternoon changing to stratocumulus by sunset, the weather will be great the next day.
Stratus: Looks like fog covering a low sky. If they come in the morning and disappear by night, that day will be clear. However, if they lie between altostratus and a canyon, it will rain.

Clouds that rise vertically

Cumulus: Fluffy clouds that you can see on a clear sky. If they disappear by evening the next day is clear, but if they can be seen late at night or float north-westerly, it is a sign that it will rain.
Cumulonimbus: Massive cloud pillars that rise to the level of cirrus. It always brings heavy rain and sometimes a thunderstorm.

If you know how to observe and analyse cloud patterns, you can predict the weather even when stranded on a desert island.

Science & Nature

Sparrow

Posted on 26/05/201112/02/2019 by Jinavie

When asked “name a bird you see often”, most city-dwellers would name a pigeon or a sparrow. These two birds are the most famous urban birds that are closely associated to humans. The sparrow, being very opportunistic and adaptable, have easily taken over environments around the globe, especially those where European settlements were made. Nowadays, they are regarded as a pest due to their foraging of agricultural crop and the spread of disease. However, citizens still view them in a positive light, especially in parks or gardens where the sparrows appear to be a “symbol of nature” (ironically, they are likely an invading species driving away native birds).

One interesting fact regarding sparrows that most people do not seem to know is how to differentiate a male and female sparrow.
A female sparrow has very soft, brown feathers, with no marked features.
A male sparrow has areas of dark brown or black feathers, especially on the head and eyes. Its beak is also darker than the female.
If one observes carefully at sparrows, they can notice that the two behave slightly differently as well.

Science & Nature

Taste Of Water

Posted on 24/05/201112/02/2019 by Jinavie

It is a common chemical fact that water is flavourless and odourless. However, most people will know that water “tastes” subtly different each time.
Taste is composed of information from taste buds on the tongue, combined with the sense of smell from your nose. Although water itself has no flavour or smell, it has many things dissolved in it such as gases and minerals that can be tasted.
This is why tap water can taste bad due to the chlorine used to treat it, or metals such as copper that have come off the pipes.

It is also well known that temperature affects the taste of water. The ideal temperature is between 10~17°C, where oxygen saturation is sufficient, giving the water a “refreshing” taste. Any hotter and the oxygen escapes, giving the water a flat taste, just like distilled water. Warm water also causes the brain to think it is saliva or mucus, sometimes producing an uncomfortable sensation. Any colder, the tongue is numbed and it loses its ability to taste.

When making tea, the ideal temperature is 70~80°C. A simple way to achieve this is by leaving a cup of boiled water for a minute or two before putting the teabag in. This is the temperature when the dissolving of the various chemicals in tea leaves is optimal. If it is too hot, bitter-tasting tannins and catechins are released in excess, whereas if it is too cool, not enough dissolving occurs.

Science & Nature

How To Make Fire

Posted on 23/05/201112/02/2019 by Jinavie

Fire has been the single most useful tool in the history of mankind – something that truly separates us from other animals. Yet, when stranded in the wild, most people are incapable of making fire as the comfort of technology has robbed us of the skill.

Obviously the easiest method is a lighter or matches.
The next easiest method is striking a flint with a knife, piece of steel or another flint. However, flints are not easy to recognise in nature unless you have experience. The following methods use minimum equipments that can often be found in the wild.
Note that you must have dry tinder to catch the spark and kindling to start the fire. Tinder is any easily combustible material that is light and fluffy, so that it quickly burns up after catching the spark.

There are two main methods: sunlight and friction.

Sunlight can be focused to create a spot of intense heat. This is a phenomenon even children use to burn things (such as insects). Instead of a magnifying glass, you can disassemble a camera to take the lens out, or use a plastic bag filled with water to make a crude convex lens.

The other method involves rubbing two pieces of wood rapidly. There are many ways to do this, with some methods being easier and faster.
The most crude method is the hand drill, often the first thing people associate to firemaking. This is when you simply rub a wooden stick in a notch in a fire board (larger piece of wood). Do this by spinning the shaft between your two palms in a fast motion. The tinder is put where it is being rubbed so that it starts burning when enough heat builds.
This is actually surprisingly tiring and hard to make fire with, so an improved method called the bow drill is used more often. This uses the same methods, but instead of your hands, you make a bow and wrap the bowstring around the shaft. This lets you spin the shaft with long forward-and-backward motions, lessening the burden. Putting a piece of wood or rock on top of the stick also prevents hurting the supporting hand.

Lastly, the fire plough method can be used. Here a groove is cut into a fire board, and a long stick is rubbed along it in a ploughing motion. The hot charcoal made is transferred to the tinder.

Once the tinder is smouldering, blow into it or swing the tinder to aerate it, fuelling the fire. This will cause the tinder to light up, which can be put in the kindling to start a fire. Slowly feed the fire with firewood (too much and you will smother it) while giving it plenty of air.
Now, you have warmth, light and hot food.

Science & Nature

Shrew

Posted on 19/05/201112/02/2019 by Jinavie

A shrew is a small rodent, similar in size to a rat, that has many fascinating characteristics.

Funnily enough, this animal has a notorious name in history. Ancient Egyptians considered shrews the spirits of darkness and the English believed that if a shrew ran over a lying animal, the animal would suffer great pain. The name shrew comes from the Middle Age English word shrewe, which meant “evil” or “scolding person”.
This is probably attributable to the putrid smell a shrew makes when threatened, and its poisonous bite.

Despite its tiny figure, the shrew has the greatest surface-area-to-weight ratio out of any mammal on the face of the Earth. Because of this, they also have a high heat expenditure, meaning they have to eat constantly to replenish the energy. This means that they sometimes die from starvation during prolonged naps.
Also, they have an extremely high heart rate, averaging about 700 beats per minute. When they are frightened, the heart rate can spike leading to cardiac arrest. For example, shrews are known to die from being frightened by the sound of thunder.

An animal that dies if it naps too much or when thunder strikes – the shrew is a very sad animal.

Science & Nature

Soul

Posted on 16/05/201112/02/2019 by Jinavie

In 1907, a physician called Duncan MacDougall tried to scientifically prove the existence of the human soul. He weighed patients dying from tuberculosis at the time of death and studied the change in body mass. After observing the death of six patients, he noted that the body mass lightens at the time of death, which he attributed to the soul leaving the dead body. He published the official average mass of the soul as 21 grams.

Unfortunately, this experiment was complete nonsense. MacDougall failed to use the scientific method. The tiny sample size of six patients, the broad range of weight loss (21 was an arbitrary number he chose and was not even the proper mean mass) and the lack of control in the study environment are some of the major flaws of the experiment procedure. In fact, it is more likely the change in body mass was due to the many changes that occur post-mortem. For example, the lungs recoil and breathe out air, moisture escapes the body and as the sphincters relax, excrements are expelled.

Many people still believe the urban myth that the soul has an objective weight of 21 grams (possibly augmented by the movie 21 grams). Another interesting fact is that MacDougall also experimented on dogs (except instead of using dying dogs, he killed them himself). He found that dogs lose no weight when dying and thus claimed that dogs have no soul.

(Source: http://ericana.deviantart.com/art/Soul-Meets-Body-80831167?q=boost%3Apopular%20soul%20%20body%20-eater&qo=5)

Science & Nature

Mentos Coke Experiment

Posted on 14/05/201112/02/2019 by Jinavie

There is an extremely entertaining experiment that can be done with two simple ingredients found in the local supermarket: Mentos mints and Diet Coke (it is more effective than original Coke). The experiment procedure is as following:

After opening the bottle, quickly drop the Mentos in to the Diet Coke. Run.

As soon as the Mentos falls in, the Coke spurts foam explosively, which shoots up to great heights. Depending on the temperature of the Coke (the warmer the better) and the number of Mentos mints (it is more effective to thread them and drop them all at once), the pillar of foam can rise to a few metres.

This fascinating phenomenon is not caused purely by a chemical reaction, but has more to do with physics. Mentos mints are coated with menthol, which has numerous microscopic dents. When it enters the Coke, the dissolved carbon dioxide forms bubbles that collect in these pits. As they collect, the bubbles expand until the pressure builds past a certain level, causing an explosion.

The most important point is that if this experiment is not performed outside, one could end up cleaning a sticky room for days.

Science & Nature

From Cell To Birth: Childbirth

Posted on 02/05/201112/02/2019 by Jinavie

The onset of labour signals that the birth of the child is imminent. Strong contractions of the uterus under the influence of oxytocin cause intense pain for the mother. This escalates as oxytocin creates a vicious cycle for more and more powerful contractions. Other signs include a bloody show, where blood and mucus leaks out, and the water breaking, where amniotic fluid bursts out as the membranes rupture.
When the cervix has fully dilated to 10cm wide, the baby is ready to come out, and this is the end of the first stage. It may take over 24 hours for this stage to be over – all the while the mother is in extreme pain as her body transforms for the process.

The second stage concerns the delivery of the baby, and follows a precise series of steps.

The baby, oriented head-down, facing either right or left, leans against the pelvis.
The baby begins to descend, passing through the pelvis.
It flexes its head as it comes through the cervix, turning towards the mother’s back as it does so.
As the head crowns, the baby turns back to its side-facing position so the shoulders can come out.
The rest of the body comes out with the shoulder. Forceps may be used to help.

The passage of such a large head and body is only possible through the massive dilation of the cervix, the stretch of the vagina, and the soft, malleable skull of the baby (a newborn’s head often looks conical and alien-shaped). Quite often, the opening of the vagina is not wide enough, and the opening may be cut open more to ensure it does not rip.

After the baby is safely delivered, the umbilical cord and the placenta are also delivered, thus ending the third stage (afterbirth). The cord is clamped and cut, and the baby is then thoroughly checked to ensure it is healthy and has no developmental issues.

Although in the past childbirth was extremely risky and often led to the death of the mother and/or baby in the process, nowadays protocols and health professionals ensure that both survive the procedure, thus ending the incredible 40-week journey until the birth of a new life. Only after understanding the arduous steps and the risks a mother takes to give birth to her child can one truly appreciate the value of life.