Tag: physics

Posted in Science & Nature

Mentos Coke Experiment

Posted on 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.

Posted in History & Literature

War Of The Currents

Posted on by Jinavie

In the late 1880s, a war raged on in the United States – one that is not commonly known by the public. It was a war between two wizards: Nikola “The Wizard of the West” Tesla and Thomas “The Wizard of Menlo Park” Edison.
This war involved no guns or explosives, but centred on something so commonplace that people take it for granted nowadays – electricity. The two scientists/wizards fought to determine whose form of electricity transmission was better.

There are two types of electric currents used for transmission.
Direct current (DC) was used by Thomas Edison, a pioneer of electricity distribution. Before him, electricity was more of a scientific curiosity and was not widely available to the public. DC is a unidirectional flow of electric charge.
Alternating current (AC) was later developed by Nikola Tesla, also a pioneer in the field of electricity. AC is the alternating movement of electric charge as it periodically reverses direction from + to -.

When electricity first became public, the industry standard was DC, as Edison started his company, General Electric. This was incredibly profitable for Edison, whose inventions relied on the usage of DC. For example, his incandescent light bulb was the principal electrical device during the time. Edison further advanced DC technology and heavily advocated it.
Tesla claimed that AC was a much more efficient mode of electricity transmission and tried to convince Edison while working for him. However, Edison ignored him and stated that it was an insane, useless idea. Edison was more an inventor than a mathematician, so he did not understand the theoretical benefits of AC over DC.

AC has the advantage of being able to use a transformer to gain much higher voltage than DC, while losing less power when transmitted. It also allowed easy conversion from low-voltage use, such as lamps, to high-voltage use, such as motors.
Despite this, Edison refused to accept the system and continued to lobby against it. The most famous case is his drastic attempt to defame AC by showing the public how “dangerous” it is.

In 1890, Edison and his company developed the electric chair, which used AC to demonstrate the safety hazards of Tesla’s invention. He did this by arranging the first capital punishment by electrocution. Unfortunately, due to calculation errors, the first shock was insufficient to kill the convict, William Kemmler. The procedure was repeated for 8 minutes, during which the convict was screaming in agony, seizing due to electrocution, and at one point, caught fire. This horrible image is portrayed quite accurately in the film The Green Mile.

Despite this unpleasant event, AC became the standard over time and DC is now only used in labs on certain special applications. Also, the electric chair was adopted as an official method of execution.

Posted in Philosophy

Formula Of Love

Posted on by Jinavie

Einstein, considered to be the greatest genius in history, once faced this situation while giving a guest lecture at a university.
A student asked Einstein, who had just finished giving a physics lecture, the following:
“Professor, you have discovered the theory of relativity and managed to formularise it. Could you express love as an algebraic formula?”

Einstein thought for a while, then smiled as he wrote this equation on the board:

LOVE = 2△ + 2□ + 2~ + 4/

The students were confused and asked him to explain it further. He then solved it as shown below:

“The sorrow of having to take a path you must take, yet not being able to resist looking back over and over! The frustration of wanting to follow a path you cannot take! That is love.”

(Source: http://xkcd.com/55/)

Posted in Life & Happiness

Feynman Problem Solving Algorithm

Posted on by Jinavie

Richard Feynman is a world-renowned genius physicist, famous for his ability of solving some of the most difficult problems in physics. He said that his intelligence was all thanks to his unique yet “normal” problem solving method, which he used to solve most of his problems. Here is the algorithm:

    1.  Write down the problem.
    2.  Think very deeply.
    3.  Write down the answer.

If that does not yield the answer:

    4.  Sleep.
    5.  Wake up, then think deeply again.
    6.  Write down the answer.

Nothing is impossible.

Posted in Science & Nature

Star Wars

Posted on by Jinavie

Star Wars is packed to the brim with epic scenes of starship dogfights. The many “pewpews” of laser cannons and massive explosions characterise this classic science fiction film series. However, this is an example of a classic “unscientific fiction”.

The great explosions of ships would never generate a loud sound as in space, there is no air or any medium to carry the sound waves. As the tagline for the movie Alien states: nobody can hear you scream in space.
In this regard, 2001: A Space Odyssey is most accurate in its portrayal of space. Not only does it have absolute silence during its scenes outside in space, but it also has accurate portrayals of space-science such as magnetic boots and rotating toilets to generate gravity.

Posted in Science & Nature

Echo

Posted on by Jinavie

Because sound is a wave, it is reflected by a surface. An echo is when this reflection is sufficiently loud and is quite common in everyday life. It is heard especially in places such as a mountain top or in a canyon because the surface needs to be quite far for our ears to detect the echo. If it is too close, as in within 340m – the distance covered by sound within one second – the echo overlaps with the original sound and cannot be heard. However, if a room is lined by a smooth surface, such as a bathroom or opera house, an echo may be heard. In these cases the delay between the sound and its echo is so close that it merely sounds as if the sound is amplified, thus explaining why singing sounds better when in a bath.

An echo can be very powerful, an example being St Paul’s Cathedral in London, England. This building is built with a giant, hemispherical roof that can amplify a whisper from one corner and replay it audibly at a corner on the opposite side of the room.
It is also very useful as it is used in technologies such as sonar and ultrasound machines to see through objects.

The word “echo” originates from a nymph named Echo from Greek mythology. Echo was instructed by Zeus to distract Hera from noticing him having an affair by chatting to her constantly. Hera caught on to this and cursed Echo to only be able to repeat what others say. After that, Echo could not even say “I love you” to the man she loved, and eventually lived in the mountains where she repeated whatever travellers said in an attempt to speak.

An interesting fact about echoes is the common myth that a duck’s quack does not echo. This is incorrect in that it does in fact echo, but since a quack is soft and fades quickly, the echo is usually too faint to be audible.

Posted in Science & Nature

Schroedinger’s Cat

Posted on by Jinavie

In 1935, Erwin Schrödinger, a famous quantum physicist, devised a thought experiment in an attempt to explain the Copenhagen interpretation of quantum physics (which posits that the state of every particle can be described by a wave function, and that the process of calculating its position determines it). It goes as follows:

A cat is placed in a box with a sealed vial of poison that is set to release when a radioactive material has decayed. As the time taken for the decay varies (roughly 50:50 chance), it is unknown whether the vial has broken after an hour if the box is closed. This also means that it is unknown whether the cat is alive or dead. To solidify this variable reality, one must open the box, whence the cat is determined as either alive or dead. 

This experiment may be hard to understand for a non-physicist, but it is still a fascinating thought experiment. This is because there are many times in life where one cannot know the outcome of something unless action is taken. Ergo, if you want a state of uncertainty, do nothing; if you want a set answer, take action. This is a particularly useful answer to someone questioning whether they should start a relationship with someone and are unsure of the outcome.

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