Tag: physics

Posted in Science & Nature

Verneshot

Posted on by Jinavie

If there is one thing we learn about dinosaurs, it is that they were wiped off the face of the Earth by an asteroid impact. Another feasible theory is that a supervolcano eruption completely destroyed the ecosystem, wiping out all life on Earth by either directly destroying them via a massive shockwave (if they were within range), or by slowly starving them as the resultant plumes of smoke would have blotted out the sun for years. But interestingly, scientists looking back over some extinction-level events of the past, discovered signs of both an asteroid strike and a volcanic eruption. This sounds to be extremely implausible, as the odds of both happening in the same era are near impossible (unless there is some extremely vengeful deity that hated the dinosaurs).

One theory that tries to explain all of this is the verneshot theory. To better understand the concept of a verneshot, imagine a cartoon character such as Yosemite Sam (the beloved red-bearded, gunslinging cowboy character on Looney Toons) shooting his gun wildly into the sky. Cartoon logic dictates that his bullets will eventually fall back on some unwary bystander. Now imagine if the Earth did the same thing, but instead of a bullet it shoots a giant piece of rock capable of causing mass extinction into the sky.

A verneshot occurs in a similar way a supervolcano erupts, where there is an incredible build-up of super hot molten rock. A supervolcano would be when this molten rock erupts as lava. In the case of a verneshot, massive amounts of carbon dioxide build up instead, leading to a pressure build-up under the crust. When the pressure becomes too much, the crust explodes, with the piece (of indeterminate size) being rocketed into space. However, the giant rock does not end up in space. Instead, it is only launched to a sub-orbital altitude, meaning it will come crashing back down to Earth due to gravity. Thus, a verneshot is when a volcanic eruption acts as a giant cannon to launch a piece of the Earth into the sky, which falls back to Earth as an asteroid-like object.

Posted in Science & Nature

Three Little Pigs

Posted on by Jinavie

The story of the Three Little Pigs is a timeless tale of how important good planning and doing things right is. Also, it serves to remind us that good architecture and engineering is key to one’s survival. A key aspect of the story is how the wolf “huffs and puffs” to blow the straw house and the stick house away. However, he cannot blow the brick house away as it is too well-built. Out of scientific curiosity, how hard does the wolf have to blow to destroy the Little Pigs’ three houses?

An experiment was performed to scientifically test this tale. The researchers built a house out of straw, a house out of sticks and a house out of bricks, then set up a fan to test at what wind speed the house was destroyed. The straw house blew away when the wind speed was 11m/s. The stick house lasted a little longer, up to a wind speed of 21m/s. Then what about the brick house? The brick house withstood winds of 35m/s, whereupon the researchers had to stop as the strong wind nearly blew the people away.

Posted in Science & Nature

Bird Strike

Posted on by Jinavie

An airplane flying across the sky faces many dangers. But a very common yet not well-known type of accident is the bird strike. Just as the name suggests, a bird strike is when a plane collides with a flying bird. This may not sound so dangerous, but considering a plane typically flies at 800~900km/h, the energy from the collision is quite significant. If a plane flying at 800km/h collides with a 5kg bird, the energy generated is 92 tonnes. This is not only enough to instantly kill the bird, but also enough to damage the plane.

The most common type of bird strikes is when a bird collides head-on with the windshield or gets sucked into the engine. The latter can cause severe damage to the engine and even cause it to fail. For example, in 1960 a plane flying above Boston collided with a flock of starlings, leading to all four of its engines failing and causing it to crash, killing 62 passengers. Since birds typically fly below an altitude of 9000m, bird strikes most often occur during take-off and landing. However, there are case reports of much higher altitude crashes, with the record being held at 11300m.

According to statistics, the most common type of bird involved are waterfowls and gulls, with 15% of bird strikes being severe. Bird strikes cause $1.2 billion worth of damage annually worldwide and has cost 200 lives since 1988. The first bird strike occurred with the invention of the airplane, as recorded by the Wright brothers (inventors of the modern airplane). As bird strikes cause so much damage, airports place many countermeasures to prevent them. The most frequently used methods are driving away birds from runways by using scarecrows and other methods, or modifying the plane and engines to be more bird-resistant.

Posted in Science & Nature

Pitch Drop Experiment

Posted on by Jinavie

When you refine crude oil, you get a black by-product called pitch, which looks like a sticky solid. However, two scientists of University of Queensland, Professors Thomas Parnell and John Mainstone, designed an experiment to prove that pitch is actually a liquid. They simply poured pitch into a funnel and placed a beaker under it to see if it will drip. Eight years after the experiment started, the first drop fell and it was found that pitch is a (extremely viscous) liquid. For the second drop to fall, another nine years had to pass, and by the time the third drop fell another nine years later, Professor Thomas Parnell had already passed away. This experiment began in 1927 and is still ongoing (the longest experiment in history) and so far eight drops of tar have fallen. The experiment is now recorded via a webcam for better observation, but in 2000, the eighth drop was never recorded due to a very untimely camera malfunction.

Posted in Science & Nature

Giant Monster

Posted on by Jinavie

A gigantic dinosaur monster of 50m height and 20000t weight appears in the centre of Tokyo! The invasion of giant spiders! These are common scenarios in science fiction films. Mankind has always been fascinated by giant creatures. Whether it be a child or an adult, no one passes by the skeleton of a Tyrannosaurus rex without being awestruck. Thus, it is very easy to use such creatures in movies. But the key point of every monster movie is the “stats”. A height taller than a high-rise building and a weight nearing one of a battleship excites people before the movie even starts. The problem is that this is very unscientific (considering it is a “science fiction”).

Let us look at the dinosaur monster first. The moment the monster steps on to land, it will be crushed like tofu. Every structure in its body will collapse and the skeleton will give way, causing 20000t of meat to crash to the ground. Simply put, the monster is just too heavy. Let us hypothesise that the monster is the shape of a gigantic T-rex. Tyrannosaurus rex was 15m tall and weighed 7t. If a 15m dinosaur is stretched to the height of 50m, the height becomes 3.3 times the original. But as the width and depth need to be expanded by 3.3 times as well, the weight becomes 37 times the original. The question is whether the monster can support its own weight. Just as the volume increased by a factor of 37, the cross-sectional area of every part of the body increases by a factor of 3.3 x 3.3 = 11. As muscle strength is directly proportional to the cross-sectional area, the strength only increases by 11 times. Thus, the load on a creature’s body is the same as the factor of expansion (e.g. there is 3.3 times the load on the monster’s muscles). But this is only when the T-rex was simply stretched. According to the stats, the monster weighs 20000t – 2800 times the weight of a T-rex. To support 2800 times the weight with 11 times the muscle, the load on the bones and muscle is 250 times. This is equivalent to having 249 people the same weight as you on your back. Of course, the monster cannot support this and its bones will become crushed and its internal organs will all burst, causing instant death.

Similarly, a giant insect monster also receives the same load as its expansion. But unlike an animal, insects have an exoskeleton instead of a skeletal system. This structure cannot support the load caused by the expansion (also, if you stretch an ant that is not even 1cm to just 10m, the load becomes over a thousand times). Ergo, the monster will collapse instantly. A giant monster is an unscientific creature that can only exist in our imagination.

Posted in History & Literature

Elements: Four Elements Of The West

Posted on by Jinavie

Human beings have believed that all matter can be divided into basic elements for a very long time. Although we now know that the basic building block of the universe is atoms, what did ancient people believe matter was made of?

In ancient Greece, the seat of Western culture, it was believed that everything was made from the four elements: earth, fire, water and air. According to Aristotle, every element has a primary and secondary characteristic, with the four characteristics being hot, cold, dry and wet. Air is primarily wet and secondarily hot, fire is primarily hot and secondarily dry, earth is primarily dry and secondarily cold and water is primarily cold and secondarily wet. He also spoke of a fifth element (quintessence) beyond the four elements. The name of the fifth element is aether and it is a pure and heavenly element that cannot be corrupted like the earthly four elements. Furthermore, it was thought that aether was the element of the sky and stars were composed of it as they were heavenly, not earthly.

The four classic elements of ancient Greece had an impact not only on physics and chemistry, but also on philosophy and culture (the concept of the four elements is popular in modern games too). The most interesting example of these is a theory by Hippocrates, the father of Western medicine, that states that the human body is composed of four bodily fluids (humours) and an imbalance between the humours caused diseases. The four humours are yellow bile (fire), black bile (earth), blood (air) and phlegm (water). Furthermore, he believed that the four humours affected personalities too. For example, an excess of black bile (“melan chole” in Greek) would cause a person to become introspective and think negatively, leading to depression or “melancholy”. This is quite possibly the first medical records on clinical depression.

The four classic elements of ancient Greece can also be found in ancient Egypt and many other ancient civilisations. It also had a significant influence on alchemy in the Middle Ages.

(Image source: http://y3rk0.deviantart.com/art/The-Four-Elements-87598175)

Posted in Science & Nature

Chalkboard

Posted on by Jinavie

The sound of fingernails scratching a chalkboard is one of the most difficult sounds to listen to. This “screech” sound gives the sensation of your soul being ripped to shreds and invokes great discomfort. Why is this?

Professor Randolph Blake of Vanderbilt Center, USA, observed that this sound is very similar to the scream chimpanzees and macaque monkeys make when they see a predator. According to other researches on this phenomenon, many species of monkeys also hate this sound greatly. Blake used these facts to hypothesise that as our primitive ancestors used this sound to alert an enemy approaching, it has been programmed into our primitive brain to trigger a negative response. Also, physically this sound amplifies in our ears at a certain frequency to cause intense pain. The pain and our basic instincts combine to generate such an unpleasant feeling.

Posted in Science & Nature

Resonance

Posted on by Jinavie

The power of vibration is incredible. Vibration allows a microwave to heat food and causes cities to be destroyed by earthquakes. The most interesting feature of vibrations is resonance, where a vibration of certain frequency greatly amplifies the vibration of another object. Every object has a natural oscillating frequency and when another wave of the same frequency hits the object, the oscillation suddenly amplifies and resonance occurs.

The best example for resonance is a swing. If you push a person on a swing at the same frequency as the swing’s natural frequency, you can achieve a much greater height than from pushing at any other frequency. Resonance can also be used to shatter a glass with only sound, by singing a sustained note at the same frequency as the glass’ natural frequency.

Resonance is how two things combine to create an even greater force.

1 + 1 = 3

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Posted in Science & Nature

Microwave

Posted on by Jinavie

The following are some strange things that happen when certain objects are placed in a microwave (and then turned on).

  • Never put metallic objects in a microwave. Metals act as an antenna, collecting the microwave and creating an electric current. This causes the metal to heat up, burning the food or melting plastic containers. Also, if the metal is pointy, it may cause an electric arc (sparks) which can be very dangerous. 
  • Ice alone does not melt in a microwave. This is because microwaves cause vibrations of particles to generate heat, but in ice the water molecules are tightly bonded and so vibration does not occur. 
  • Microwaves can cause something called superheating of liquids. This means that the liquid is heated to beyond its boiling temperature without boiling. A superheated liquid can spontaneously begin to boil in an explosive manner when disturbed. This is dangerous as it can mean that a cup of boiling hot water may suddenly explode in your face.
  • Certain foods are known to generate sparks in a microwave. For example, when two oblique slices of chilli pepper are placed near each other point-to-point, a flame sparks between the two points from the arcing electricity. Grapes do the same thing.
  • Some foods such as grapes and eggs explode in a microwave. This is because of the pressure building up within it from all the steam being released all at once. This is amplified with something like an ostrich egg where the shell is strong enough to contain an immense pressure. But when a certain pressure is reached, the egg will literally explode and send shrapnels of microwave pieces flying out like a bombshell.
  • A piece of garlic will spin rapidly in a microwave as garlic has a thin tube running on one side. As water evaporates, the vapours rush towards both ends causing the garlic to spin. Also, if you cut the bottom of a clove of garlic then microwave it for about 15 seconds, the pieces of garlic will pop out easily.
  • As explained above, metal conducts microwaves and generates a current. This is most obvious when a CD is placed in a microwave, where sparks dance on the surface (assuming the reflective surface is facing up). Similarly, a fluorescent tube will light up in a microwave from the electricity generated.
  • Placing an open flame, such as a lit candle, inside a microwave produces a very strange phenomenon. The naked flame will become ionised plasma and shoot up to the ceiling of the microwave. This is observed as a ball of light floating around. Note that this is extremely dangerous and most likely will destroy the microwave.

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Posted in Science & Nature

Grandfather Paradox

Posted on by Jinavie

Is time travel possible? In 1943, a science fiction writer called René Barjavel posited the following paradox.

A man travels back to the past and kills his biological grandfather before he meets his grandmother. Thus, his grandparents would not have sired a son (the man’s father) or daughter (mother), which then suggests the man could not have been conceived. If so, who killed the grandfather? As there was no one to kill the grandfather, he would have had a child and the man would ultimately be born, travelling back to the past and killing his grandfather. This paradox suggests that time travel is impossible.

Some people use the parallel universe theory to argue against the paradox. They suggest that as soon as the man travels to the past to kill his grandfather, an alternate universe is created where the grandmother meets a different man and the course of time is changed. This is a valid theory but the grandfather paradox still holds strong in disproving time travel. However, the grandfather paradox only states that travelling back in time is impossible; it says nothing about time travelling to the future.