Tag: electricity

Posted in Science & Nature

Thuder And Lightning

Posted on by Jinavie

The best or worst part (depending on your preference) about a dark and stormy night are the majestic flashes of lightning and booming thunder. Most people confuse the two terms, typically using “thunder” to describe both, but technically thunder is the sound produced by lightning, which is the flash of light. Lightning occurs when dense clouds become electrically charged due to the collision of water molecules. As charge builds up, the cloud becomes negatively charged. The negative charge becomes so intense that it begins to push electrons towards the surface of the Earth, creating a positive charge. Electricity always flows from a negative charge to a positive charge through a medium. The intensity of charges causes the air to become ionized (plasma), making it suddenly conductive and allowing the electricity to flow from the cloud to the ground. This is seen as a flash of intense light. As the electricity travels through this channel of air, it superheats the air and causes a massive expansion of air, much like an explosion. This creates an intense shockwave burst, producing a sound that we call thunder.

Lightning is a deadly force of nature. It clocks a peak voltage of somewhere between 30 million to billions of volts – far exceeding the electricity that can be generated by humans. When a lightning bolt strikes a human, it has a mortality rate of between 10~30%. The two effects of lightning on the human body is electrical shock and heat. As lightning flashes over the skin to reach the ground, it leaves a striking pattern known as Lichtenberg figures (see below), showing the path of the electrical breakdown. The intense electrical burst can cause loss of consciousness, arrhythmia or sudden cardiac arrest. The heat generated by the electricity can cause severe burns both externally and internally. It can literally fry internal organs causing permanent damage to the heart, lungs and brain. Neurological symptoms such as amnesia, confusion, sleep disturbance and chronic pain have also been reported. Strangely, there are also reported cases of lightning curing ailments such as blindness, deafness and baldness.

image

Because lightning is light and thunder is sound, one can calculate how far away lightning struck using the time between the lightning flash and the sound of thunder. Sound travels at 340m/s, so by multiplying the number of seconds between the lightning and thunder by 340, you can deduce the distance in metres. For example, if you see a lightning strike and then hear thunder after 7 seconds, the lightning must have struck 340m x 7s = 2380m = 2.38km away.

image

Posted in Psychology & Medicine

Viscera: Heart

Posted on by Jinavie

(Learn more about the organs of the human bodies in other posts in the Viscera series here: https://jineralknowledge.com/tag/viscera/?order=asc)

Out of the numerous organs found in the human body, the heart is perhaps the most well-known. This is probably because since the dawn of time, man has put his hand on his chest and felt the rhythmic pounding of his heart – a reminder that he is alive. The function of the heart is to pump oxygenated blood from the lungs to the rest of the body via the circuit of blood vessels (vascular system).

The heart relies on electricity to pump blood in a rhythmic, autonomous way. Because of this property, a heart will beat on its own even if you took it out of the human body. Every muscle in the human body requires an electrical impulse for it to contract. This is also the case in the heart, but unlike the skeletal muscle in other parts of the body which receive their impulses from the brain and spinal cord, the heart has its own source of electricity.

The heart has a small group of pacemaker cells in the right atrium called the sinoatrial node, which always fires electrical impulses at a set rate and rhythm (sinus rhythm). The SA node will do this without any instruction from the brain. The impulse from the SA node spreads throughout the atria of the heart, causing the atrial muscles to contract simultaneously to squeeze blood into the ventricles. The impulses then reach the atrioventricular node, which filters the signals and sends a stream of electricity through a wiring system known as the Purkinje fibres. These fibres act like a high-speed internet cables running down the centre of the heart, sending rapid signals through out the ventricles to induce a strong, cooridnated contraction in both ventricles. This causes blood to be forcefully squeezed out through the two outlet vessels of the heart: the pulmonary artery (to the lungs) and the aorta (to the rest of the body).

image

Although the SA node is completely autonomous, it can be controlled using hormones, nerve signals and medications. For example, adrenaline will speed up the rate the heart beats at while massaging the carotid arteries in the neck will slow the heart down.

One thing people wonder about is what the doctors listen to when they put a stethoscope to a patient’s chest. Everyone knows the heart makes a rhythmic “lub dub” sound as it beats away, but what information could that give away? A doctor can gain much information about the heart from a cardiac examination by taking the pulse and blood pressure, but listening to the heart (auscultation) may reveal a medical sign known as a murmur. A murmur is any added sound other than the normal “lub dub” sound of the heart. For example, a heart with aortic stenosis may give the sound “shhhhhhh” as if it was giving off static. This sound is produced when blood flow in the heart is turbulent and not smooth. This may be for a number of reasons but the most common reason is because the valves of the heart are not functioning properly. For example, the valve between the left atrium and left ventricle may be leaky (mitral regurgitation) or the valve at the start of the aorta may be stiff and narrowed (aortic stenosis).

By carefully listening to the sound the heart makes, an experienced doctor may pick up on such structural abnormalities even without the use of fancy medical imaging technologies.

Posted in History & Literature

Torture

Posted on by Jinavie

Travelling is fun. But strangely, the etymology of the word travel is the Latin word tripalium, which means “torture instrument”. This is most likely because in the old days before airplanes and trains were invented, travelling was often long, arduous and painful. Travelling is probably the least terrifying form of torture. Let us explore the various methods of torture used throughout human history. There are many types of tortures, but they can be largely divided into physical and psychological torture. The main goal of torture is to induce maximum pain to extract information from, punish or to execute a person.

Physical torture is very simple: inflict as much pain as you can. For example, you can simply tie the person to a chair and beat them senselessly, or apply pressure to a wound to cause intense pain. A useful tip for beating someone is to place a phonebook on their stomach or hand and hitting the book, which transfers pains while not leaving a bruise or any marks. A simple way to cause extreme pain is the use of fingers. Finger tips are extremely sensitive and contain many nerve endings, meaning sticking needles under the nail bed or ripping the fingernails off causes extreme pain. Like this, medical knowledge has often been used to develop new ways to torture people. For instance, heating the sole of the feet with fire causes severe pain, electricity used in the right amount can keep the person alive while causing pain and seizures, and if you lie a person flat and on a slight decline (so the head is lower than the body), put a cloth over their face and pour over it, you can induce a sensation of drowning (this is called waterboarding and is used by the CIA). Another simple, effective torture method is the joori-teulgi(주리 틀기) from Korea, where a person is tied to a chair with the feet bound, with two long sticks inserted between the thighs, crossed, then pulled down to streth the thighs apart. This causes extreme pain and suffering.

As mentioned above, torture can be used to kill a person too. The famous hanged, drawn and quartered torture was used in the Middle Ages to punish treasonists. The convict was drawn behind a horse for a while and then hanged until just before death, when they were disembowelled, beheaded and quartered. Another strange, complicated method of torture can be found in China, where slow slicing was used. Slow slicing involves tying a convict to a post and cutting slices of flesh off him until he dies. Executioners often had an art of slicing in such a way to prolong the suffering for as long as possible without killing the person. Another execution method found in both Western and Eastern history is dismemberment by horses, where the person’s four limbs and head are tied to individual horses (or cows), which are then made to run in different directions to violently rip the person up.

Animals were used in various forms of torture throughout history around the world. Tying the prisoner to an elephant’s feet to crush them to death, putting a rat on the person’s stomach then putting a pot over it and heating it with fire to make the rat burrow into the person’s guts, feeding them to lions or vicious dogs, coating them in honey and leaving them in the path of fire ants to make them get slowly eaten… Out of all of these, the most bizarre method is the goat torture used in ancient Rome. This torture involved tying the prisoner to a chair and securing their feet, which were coated with salt water. Next, goats were released around the prisoner. The goats would lick the sole of the feet to cause tickling, which over a prolonged period is interpreted as pain by the body. This eventually drives the person insane from pain.

Unlike physical torture, psychological torture induces shame and fear rather than pain. Threatening, solitary confinement, sleep deprivation, rape and sexual torture, sensory deprivation, exploitation of phobias, loud noises (such as banging on a door constantly), blindfolding the person and rubbing a balloon on their cheeks, placing foreign objects or snakes in the anus or vagina, leaving them in a container full of insects… Psychological torture has just as much a variety as physical torture and can have longer lasting effects on the person. Furthermore, as it leaves no external marks, it is still frequently used in the modern day.

No matter what the method, inducing extreme pain to control people, extract information and cause suffering is an inhumane act that cannot be tolerated. If mankind had focussed their creativity and effort into more constructive and altruistic things rather than discovering various ways to cause pain, we would probably be living in a much better world.

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.

image

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 History & Literature

Electrical Appliances

Posted on by Jinavie

The following are the first five domestic appliances to be electrified:

  1. Sewing machine
  2. Fan
  3. Kettle
  4. Toaster
  5. Vibrator

The vibrator was electrified a decade before the vacuum cleaner or the iron.

Posted in Psychology & Medicine

Flatline

Posted on by Jinavie

When people think of the word “flatline”, they immediately visualise a medical crisis where a patient is lying unconscious, with doctors and nurses shouting out medical terminology while administering drugs, all to the suspenseful music and apathetic monotone and single horizontal line on the ECG machine. The doctor then shouts “Clear!” and proceeds to shock the patient with two paddles. This is repeated until some structures appear on the ECG, symbolising that the crisis has been resolved.

Of course this is a scene from a typical medical drama. Television shows, especially medical ones, are notorious for sacrificing medical accuracy for the sake of drama and tension. The “flatline” is the most cliché, repeated mistake made by almost every medical television show ever made.

The proper terminology for a flatline (a colloquial term), is asystole. This means that there is no systole, or contraction of the heart. An ECG (electrocardiogram) measures electrical signals in the heart, and in asystole there is insignificant amounts of electric activity, and the classic QRS complex is not seen. In this state, the heart is not pumping any blood and is electrically silent, meaning that the patient is clinically dead.

When asked how to treat this condition, the majority of people (even medical students) will shout “Shock!” or “Defibrillate!”. Defibrillation is the administering of an electrical shock to try “reboot” the heart, and correct the fibrillation – the chaotic electrical signal interfering with the normal, rhythmic electrical activity. Unfortunately, this is completely wrong yet so often depicted on television and films.
As asystole is a state of no electrical activity, there is no fibrillation to remove, nor is there anything to reset. Defibrillation in this state may even cause harm, causing tissue damage and lowering the chance of survival.

The correct treatment is injecting adrenaline (epinephrine in the U.S.A, atropine may be administered also) and CPR. Unfortunately, asystole is a condition that cannot be reversed, unless the heart somehow restores its own electrical activity. CPR merely keeps the patient’s perfusion going to preserve the organs for a longer time. Ergo, asystole signifies certain death, especially after 5 minutes where the heart will not respond to any drugs or electric shocks. In fact, asystole is one of the conditions required for the certification of a patient’s death.

Another related example of a (potentially fatal) misrepresentation of medicine in the media is the adrenaline injection. As mentioned before, this is the treatment for asystole. However, it is administered intravenously (into a vein) and never directly into the heart as in Pulp Fiction. This is more likely to kill the patient than save them, as the heart muscles could be damaged and delicate coronary arteries may become ruptured.

So why is it that the media continues to depict such blatant errors, that set a “common sense” that affect even medical professionals? This is most likely due to the audience wanting to see a dramatic scene, in a gripping life-or-death situation with drastic, powerful action. For example, the audience would much rather see the use of paddles or a giant needle being stabbed into the patient than seeing continuous CPR with no showy movements.

The next time you watch a medical television show, count how many times the doctors try to defibrillate a flatline.

image