Tag: explosion

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 Psychology & Medicine

Phineas Gage

Posted on by Jinavie

On September 13, 1848, a 25-year-old foreman named Phineas P. Gage was working on a railroad with his work team. In an unfortunate turn of events, as he was using a tamping iron (large iron rod with a pointed end, measuring 3 feet 7 inches in length and 1.25 inches in diameter) to pack gunpowder into a hole, the powder detonated. The forceful explosion drove the metal pole skyward through Gage’s left cheek, ripped into his brain and exited through his skull, landing dozens of metres away. His workmates rushed to Gage’s assistance (who they presumed to be dead at the time of the accident), and to their surprise, found that he was still alive.

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In fact, Phineas Gage spoke within a few minutes of the incident, walked without assistance and returned to his lodging in town without much difficulty – albeit with two gaping holes in his head, oozing blood and brain everywhere. He was immediately seen by a physician who remarked at his survival. In fact, it is reported that he was well enough to say: “Here is business enough for you” to the doctor. Another physician named Dr John Harlow took over the case, tended to the wound, fixed up the hole and recorded that he had no immediate neurological, cognitive or life-threatening symptoms.

By November, he was stable and strong enough to return to his home, along with the rod that nearly killed him. His family and friends welcomed him back and did not notice anything other than the scar left by the rod and the fact that his left eye was closed. But this was when things started to get interesting.

Over the following few months, Gage’s friends found him “no longer Gage”, stating that he was behaving very differently to the man who he was before the accident. Dr Harlow wrote that the balance between his “intellectual faculties and animal propensities” had seemingly been destroyed. Gage became more aggressive, inattentive, unable to keep a job, verbally abusive and sexually disinhibited. He would frequently swear using the most offensive profanities and would be as sexually suggestive as a March hare. How did the iron rod cause such a dramatic change in Gage’s personality?

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Phineas Gage would go on to be one of the most famous patient case histories in the history of modern medicine. His case was the first to suggest some sort of link between the brain and personalities. Neurologists noted that the trauma and subsequent infection destroyed much of Gage’s left frontal lobe – the part of the brain that we now attribute to a person’s logical thinking, personality and executive functions. It is in essence the “seat of the mind”. Ergo, Gage’s loss of one of his frontal lobes meant that his control of bodily functions, movement and other important brain functions like memory were undisturbed, while his “higher thinking” was essentially destroyed (he was essentially lobotomised). This explains Dr Harlow’s observation of his “animal propensities”.

Thanks to this case, a great discussion was sparked and the idea that different parts of the brain govern different aspects of the mind was conceived. We are now able to localise almost exactly where the language area is, what part controls movement and how a certain piece of the brain converts short-term memory into long-term memory.

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Posted in Science & Nature

Units

Posted on 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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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 History & Literature

Mary Celeste

Posted on by Jinavie

In 1872, a ship by the name of Mary Celeste was spotted off the Azores in the Atlantic Ocean – completely intact and undisturbed aside from its missing crew. Not a single person, alive or dead, could be found, despite everyone’s personal belongings still sitting undisturbed where they had been left. Even little things such as valuables and piano music were right where they should have been. It was as if its crew had simply evaporated. There were no signs of a struggle and no cargo was missing. To this day, the case of the disappearing crew of the merchant ship Mary Celeste is one of the most famous maritime mysteries in history.

So what happened to the ship’s crew? Historians have been trying to figure out their fate for decades, but the question was finally solved by scientists. One fact that is known about the Mary Celeste is that of its cargo of 1701 barrels of alcohol, 9 were empty. Although an obvious answer is that the sailors went overboard with a party, the truth is even more spectacular. In 2006, Dr. Andrea Sella, a professor of chemistry at University College London, created a replica of the Mary Celeste’s hold to find out how to create an explosion without leaving a trace of fire. He simulated a leak of the ship’s nine barrels of alcohol and found that once the vapour was ignited, say by a pipe or a spark, it created a pressure-wave type of explosion. There was a spectacular wave of flame but, behind it was relatively cool air. No soot was left behind and there was no burning or scorching.

Ergo, the mystery of the Mary Celeste is most likely as follows: there was a leak of the alcohol, the vapour of which fuelled a massive ghost explosion that swept through the ship. The sailors, completely unscathed but utterly horrified, would have piled into the ship’s lifeboat without any useful things like food or water, eventually sinking or dying of thirst and exposure. The Mary Celeste would have still looked perfectly fine as it drifted the vast ocean, all by itself.

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

Nuclear Explosion

Posted on by Jinavie

Nuclear weapons are quite possibly the most dangerous weapons mankind has ever developed. Through the use of nuclear fission, atoms are split to release the massive amounts of energy contained within, causing a gargantuan explosion. When a typical nuclear bomb detonates, energy is released in various forms: blast energy (40~50%), heat (30~50%), radiation (5%) and fallout (5~10%). The distribution of the energy varies according to the type of bomb (e.g. neutron bombs produce significantly more radiation than heat and blast energy).

The initial damage that follows a nuclear explosion is from the blast energy, much like a conventional weapon. The sheer amount of kinetic energy creates a shockwave that pulverises everything in its path, travelling at speeds over 1000km/h. In addition, the heat from the explosion, over ten million degrees celsius at one point, causes vaporisation of all matter within a certain radius, causing a massive release of gases, fuelling the shockwave from the expansion. In the case of the bomb that destroyed Hiroshima, all structures within 1.6km were vaporised and those within a 3.2km radius suffered moderate to severe damage. A modern nuclear weapon is at least tens of times more destructive and will affect a significantly larger area.

At the same time, thermal radiation spreads out in all directions much like sunlight. Thermal radiation travels far further than shockwaves and can cause severe burns and eye injuries (flash blindness) to people in the vicinity (if they are close enough, they will spontaneously combust or melt). Near ground zero (point of explosion), a firestorm may erupt from the sheer amount of heat energy, as observed as a fireball. 

Next comes the indirect effects.
Ionising radiation is produced when atoms are split and these have detrimental effects on living organisms. Not only are they responsible for mutations in the genome, leading to deformed offspring, sterility and cancer, but if there is sufficient radiation, a person will immediately die from acute radiation poisoning.
The same radiation, especially gamma rays, creates what is called an electromagnetic pulse (EMP). EMP is caught by metal objects and induces a high voltage surge, destroying unshielded electronic devices. Sometimes, nuclear bombs are detonated at very high altitudes so that only the EMP affects the ground, damaging enemy communications and destroying entire power grids.
Lastly, radioactive material rains from the sky for long periods of time, also known as fallout. Fallout causes continuous radiation damage in affected areas.

A nuclear bomb is truly a weapon of mass destruction as it utilises various forms of destruction to devastate all life forms within an area spanning several kilometres, even killing over the course of time in the form of radiation.

Posted in Science & Nature

Fire

Posted on by Jinavie

Every creature on earth knows the fearful power of fire. Learning how to utilise it is possibly one of man’s greatest achievements, as it allowed science and technology to kickstart in every way. However, we still lose control over it sometimes and suffer the consequences. Fire can develop from a tiny ember to a full-blown firestorm that incinerates everything in its path. The following are the four stages of fire development:

  • Stage 1 – Incipient stage: No visible smoke and very little heat. Small fire.
  • Stage 2 – Build-up stage: More heat causes pyrolysis (decomposition of material due to heat), releasing combustible gases. May cause a flashover (every combustible surface in the room ignites all at once).
  • Stage 3 – Fully-developed stage: Visible flame, massive amounts of heat, smoke and toxic gases. Everything is burning.
  • Stage 4 – Decay stage: Fire is either contained or extinguished. If not, may spread to other areas (e.g. the next room).

After sufficient heat has built up, fire spreads almost explosively (sometimes literally) causing extensive damage. Thus, the most important part is preventing the fire in the first place or extinguishing a small fire still at the incipient stage. As powerful a tool it may be, it can also destroy everything you hold precious within a matter of hours.

An interesting phenomenon related to fire is backdrafts. This is similar to flashovers (described above) except it is triggered by oxygen rather than a build-up of heat. Both cause a sudden transition from a small fire to a full-scale inferno.
A backdraft occurs when a burning room is filled with pyrolysed, combustible gases but lack the oxygen needed to continue burning as it was used up while the fire was building up. When a firefighter or a broken window causes air to rush into the room, the pressure in the room spikes and every combustible material suddenly bursts into flames, exploding out in a ball of fire. Backdrafts are one of the most dangerous fire phenomena that claim the lives of countless firefighters.

Posted in Science & Nature

Badass Weapons Of Nature: Bombardier Beetle

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The bombardier beetle, or Brachymus creptians, has a “machine gun”. When attacked, it makes an explosive sound and spouts smoke.
This beetle combines chemicals from two separate glands to make the smoke. 
The first gland produces a solution of 25% hydrogen peroxide and 10% hydroquinone, while the second gland produces peroxidase, an enzyme that catalyses the reaction. When these solutions are combined and heated to 100°C, smoke and nitric acid vapour is produced and explosively released.

If you put your hand close to a bombardier beetle, it will rapidly release a scalding, noxious, red vapour. This nitric acid will cause blisters on afflicted skin.
Bombardier beetles also know how to aim the tip of its abdomen to target an enemy. Via this method, it can hit a target a few centimetres away. Even if it misses, the explosive sound will scare away any predator. 
Normally, bombardier beetles store enough chemicals for three or four shots. However, some entomologists have found that some species can fire up to 24 times in rapid succession if provoked.

As these beetles are a bright orange and silver-blue colour, they are very noticeable. They act as if they do not care if they are seen, as they are equipped with an effective cannon. Generally, beetles with a colourful coat have a unique, ingenious defensive mechanism to ward off curious animals and insects.
Despite this, rats that know that the beetle loves to use this “ingenious defensive mechanism” quickly grab the beetle and plant its abdomen in the ground. After attacking it continuously while in the ground to exhaust the beetle’s rounds, the rat bites off the head first.

(from the Encyclopaedia of Relative and Absolute Knowledge by Bernard Werber)

Posted in Science & Nature

Badass Weapons Of Nature: Carpenter Ant

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There is an extreme number of ant species, each with a unique characteristic. In the case of carpenter ants, they are famous for their strange defence mechanism.

Some species of carpenter ants, such as the Camponotus saundersi, have warrior ants with very large mandibular glands (many times greater than normal ants). When in a battle it judges that it has no chance of winning, the ant rapidly contracts its abdominal muscles to build pressure. When sufficient pressure is reached within the mandibular glands, it explodes violently, shattering the ant in the process. The glands are filled with a sticky, toxic fluid, which is spread all around where the ant used to be, ensnaring the foes. The inflicted enemies are killed by the poison. 
This is the reason why they are sometimes referred to as exploding ants.

It is a bold, yet fearsome sacrifice for the greater good.