Photon #1 - May 2019 by The International School Bangalore

photon a TISB publication

#1 The first edition of TISB's first physics publication

Plasma Grapes

pg 15

How hard do you have to slap a chicken to cook it? pg 20

N O N - N E W T O N I A N F L U I D S Newton thought that no amount of stirring or similar actions would change the viscosity of a fluid. If youâ&#x20AC;&#x2122;ve eaten yogurt recently, you know that this isnâ&#x20AC;&#x2122;t quite the case ! ON PAGE 22

ALBERT EINSTEIN:

THERE ARE ONLY TWO WAYS TO LIVE YOUR LIFE. ONE IS AS THOUGH NOTHING IS A MIRACLE. THE OTHER IS AS THOUGH EVERYTHING IS A MIRACLE.

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EDITORIAL

PAGE 3 FROM THE PHYSICS CLUB

PAGE 8

PLASMA GRAPES PAGE 15

co INTO THE 2D BACK AGAIN PAGE 16

LIGHTNING

PERFECT MIRROR PAGE 17 PAGE 19

nt HOW TO COOK A CHICKEN WITH PHYSICS

PAGE 20

JOKES

PAGE 26

PAGE 30

GALILEOâ&#x20AC;&#x2122;S CRUCIFIX

PAGE 14

PAGE 18

AEROPONICS

PAGE 6

LASER COOLING

HOW DO CARS PAGE WORK 10

PAGE 22

QUANTUM COMPUTING

PAGE 4

PAGE 10

COVER STORY

PAGE 28

GREAT MINDS

ARE PHYSICS AND BIOLOGY REALLY RELATED? PAGE 32

STATUS UPDATE

PAGE 27

LETTER FROM THE EDITORS We really enjoy physics! Trying to visualise and reason through the various phenomena we observe around us and use them to our advantage is something that really intrigues us. Honestly, we feel disappointed when people say that they can’t stand physics. Something so beautiful and something so essential to our existence is held in utmost regard by us and we believe the same should be true for all of you. That’s the reason why we decided to start this magazine and the reason you are reading this right now. We wanted the students who already enjoy physics to spread the love through self-written articles about topics they find interesting. We believe physics is much more than just completing your IAs or scoring in your exams. This edition’s cover story is about Non-Newtonian fluids, something which common in the world of physics.

We would like to thank the editorial team, the students who sent submissions and everyone else who made this possible. With this, we leave you to it. Read, observe, explore and dive deep into this awesome subject with the first ever edition of Photon! Happy Learning!

From the editors Aditya Gaur and Aryan Gupta

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seems normal but behaves peculiarly when observed properly: something very

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GREAT MINDS

RICHARD FEYNMAN BY AGASTYA RANA

Welcome to the inaugural edition of Photon's very own column - Great Minds. We will take you through a biographical journey of one eminent physicist every issue, and we will discuss their own unique contribution to their field. Our first installment of Great Minds highlights one of the most eminent physicists of the 20th century, who pioneered a formulation of Quantum Mechanics, developed Quantum Electrodynamics (QED) and worked further on particle physics. If you don't know which fields we are referring to, please do read on!

Feynman was one of the few great minds in physics who took an active interest in popularisingÂ physics, both in the classroom and for the general public. Most famous among undergraduates for his extensive and comprehensive three volume Feynman Lectures on Physics, Feynman revolutionisedÂ the teaching and introduction of physics, making it much more of a creative and unknown science than the formulaic procedures learnt in school might suggest.

Later in college, he received the highest score in the most challenging math exam there is the Putnam Mathematics Competition. At MIT, his undergraduate major shifted from math to electrical engineering and eventually settled on physics - as he started working in quantum mechanics (the mind-bending science of the very small). After graduating from MIT, he achieved the full score in the Princeton graduate school exams in Physics, which was unheard of at the time. He received a PhD from Princeton with a doctoral thesis that laid the groundwork for an entirely new formulation of quantum mechanics which drew parallels with classical mechanics itself. Feynman later worked at Cornell and Cal Tech, receiving multiple accolades for his work. He also spent a brief period during World War II working on the Manhattan Project, which he contributed to greatly even though he was at heart a theoretical physicist. Many compared Feynman to Einstein and Lev Landau (who you might see featured here in the next edition), for his grasp on complex theoretical physics as integrated seamlessly with math. His interpretation of Quantum Mechanics introduces many far-fetched ideas, so intriguing that they inspired the next generation of physicists (ourselves included) enter the field. According to his formulation, the positron (the antiparticle of an electron - the same mass but the opposite charge) was not a separate 'antiparticle' of the electron as was the consensus at the point in time,

but instead is simply an electron moving backwards in time. By introducing the idea of moving along both directions in time - with mathematical justification of course - Feynman broke the stigma of time only being able to move in one direction, which puzzles many physicists to this day. Continuing his work on quantum mechanics, Feynman played a major role in reconciling theories of QM and Special Relativity in a brand new branch of physics - or what he calls the 'jewel of physics' called quantum electrodynamics. During his work in this field, he invented a new visualization format to understand the interactions between leptons and fermions (ordinary 'particles') as mediated through bosons (force-transmitting particles), which now find ubiquitous usage in high school and university classrooms as Feynman diagrams. Nevertheless, as mentioned above, we believe that Feynman's greatest contribution to physics were his timeless Lectures which were delivered to a group of lucky CalTech students and were later transcribed for the public, summarizing all that there is to know in physics into just three concise volumes - volumes which have spurred budding minds to pursue the elegance and simplicity that is plentiful within the pages of those books. If physics is something that you feel might interest you, I urge you to give these books a read. Even if you take more of a casual interest in science, you might enjoy his semi-biographical books, including my personal favorite, Surely You're Joking, Mr Feynman.

A Feynman Diagram

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Feynman's intellect showed at a young age - a young engineer, Feynman created a home burglar alarm system during his high school years. He taught himself all of pre-calculus and calculus when he was 15, and before entering college, he was playing with a formulation of the half derivative (when taken twice, the result is the ordinary first derivative).

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FROM THE HISTORY CLUB

GALILEO’S CRUCIFIX HARI KRISHAN CHOUDHARI

Galileo Galilei is a person who needs little introduction: if he sent in an application to any job today, his CV alone would be enough to guarantee him acceptance anywhere. He invented the pendulum clock, the geometric compass, the first rudimentary thermometer (the thermoscope), the first compound microscope (disputedly), and a telescope with magnification of 20x. This last invention acted as the catalyst for the discovery of craters on the moon, sunspots, the phases of Venus, the rings of Saturn and, most famously, discovery of the four most massive moons of Jupiter, now known as the Galilean moons. If that wasn’t enough, he also proved constant acceleration due to gravity on the side. What a guy.

Now, these discoveries and innovations were definitely extremely ground breaking in the fields of astronomy and physics, but no good deed goes unpunished: as Galileo tried to bend the arc of early Renaissance Europe towards progress, the Catholic Church worked as hard as it possibly could to bend that arc all the way back. But why would the Church have a problem with these seemingly harmless discoveries and observations? For the answer, we need to jump over to over a millennia before Galileo’s birth and understand the power and influence of the church at the time.

However, Galileo’s observations threw a spanner in the works. His observations of the phases of Venus proved that Venus revolved around the Sun, not the earth. In addition, Aristotle’s conception that the heavenly bodies were composed of a perfect material (aether) was disproven by the Galileo’s observation of craters on the moon. As Galileo propagated these discoveries and observations in support of Nicolaus Copernicus’ heliocentric theory (in which the planets, including earth, revolved around a stationary sun), the growing popularity of his ideas brought him the censure of the church, who launched an inquisition against him in 1616. It’s judgement was that the heliocentric proposition is “is foolish and absurd in philosophy, and formally heretical”, 5and Galileo was ordered to cease from propagating it. Galileo, however, defied this order, and published “Dialogue Concerning the Two Chief World Systems” in which he mocked and ridiculed proponents of the Geocentric model. This snapped the patience of the Vatican, and Galileo once again faced inquisition in 1633 with a much harsher outcome: he spent the rest of his life under house arrest, and the Dialogue was banned from publication. So, that was Galileo’s fate, his reward for all of the advances he made. From our modern standpoint, his treatment seems appalling, accustomed as we are to the open nature of scientific exploration today. However, I will leave the reader with this thought: can an argument be made that it was just? That to let Galileo flout authority and undermine the Church that held together Medieval Europe, for the sake of an impractical subject like Astronomy, would have brought more catastrophe and upheaval than it was worth? In the modern world of rapid scientific innovation, this is a question that needs to be considered.

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Aristotle (384-322 BCE) was a philosopher back in Ancient Greece. Another guy with an impressive resume, he wrote texts on almost every subject imaginable, from astronomy to physics to ethics. I remember him as the dude who was wrong about almost everything: I mean, he thought that some people were naturally born slaves and that it was both fit and just for them to be slaves. But his more spectacular mistake was his model for the Geocentric universe. Aristotle proposed that the heavens were literally composed of concentric, crystalline spheres to which the celestial objects were attached and which rotated at different velocities (but the angular velocity was constant for a given sphere), with the Earth at the center. The sphere of the stars lay beyond the ones of the planets; finally, in the Aristotelian conception there was an outermost sphere that was the domain of the "Prime Mover". The Prime Mover caused the outermost sphere to rotate at constant angular velocity, and this motion was imparted from sphere to sphere, thus causing the whole thing to rotate. In the absence of sufficiently advanced telescopic equipment, this was a logically coherent model that sufficiently explained most observable astrological phenomena. By the Middle Ages, such ideas took on a new power as the Prime Mover of Aristotle's universe became the God of Christian theology, the outermost sphere of the Prime Mover became identified with the Christian Heaven, and the position of the Earth at the center of it all was understood in terms of the concern that the Christian God had for the affairs of mankind.

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SONOLUMINESCENCE

FROM THE PHYSICS CLUB Do you want to stroll down a phenomenon which has not been termed in the dictionary yet? Do you want to defy the laws of physics? Do you want to make the dream of creating energy on earth a reality? If that is the case, then you have spotted the right article for provoking your imagination and developing your interest in physics. The complexity of this word very well defines how captivating this topic is: Sonoluminescence occurs when a small gas bubble is acoustically suspended and periodically driven in a liquid solution at ultrasonic frequencies, resulting in bubble collapse, cavitation, and light emission. Now many of you might be wondering what exactly that means? Well, to put it simply, when sound is passed through water, a bubble forms which converts sound energy into light and thermal energy. Research has found that the temperature of this bubble exceeds temperatures of 6000K which is hotter than the sun.

Thus, it is believed that, in this phenomenon, energy is not only converted but also created through nuclear fusion. Therefore, this experiment is more popularly recognized as ‘star in a jar’ experiment because the bubble resembles the properties of a star which also creates energy through nuclear fusion. An even more fascinating fact is that the experiment is simple enough to be carried out in a school laboratory through a setup similar to the one shown below.Amusingly enough, the discovery of this phenomenon was an accident. In 1934, two German scientists discovered the phenomenon as a result of videoing their experiment. Since then, many researchers have delved deeper into the topic, but we are yet to have an accepted theory. There have been many interesting theories including one which claimed the emitted light to be a form of Hawking radiation which compares the process of Sonoluminescence to a process that occurs in black holes! Other theories include Triboluminescence, and Shock wave SL. It may be beyond the scope of this article to cover the ideologies behind this theory. (Note: you could choose to read the references for more information.) One of the most intriguing and most debating fact is that the insertion of a noble gas increase the heat and light produced by the bubble dramatically. There is no clear cut reason for why this happens. We all know that noble gases do not react, hence, making this phenomenon a peculiar one. A possible explanation is that as the number of electrons increase in the stable homo nuclear atoms, the intensity of the emissions increases due to the atom's nonconductivity. While exploring this nerve racking phenomenon, researchers have also found that plasma physics is used during the process (which provides evidence for nuclear fusion; the process that creates energy in stars). It was noted that the bubble has an inner core of plasma through videography analysis and experimental, research based evidence.

The most surprising fact is that they can also control the intensity of light they emit.These organisms can bundle the luciferin with oxygen in what is called a “photoprotein”—like a pre-packaged bioluminescence bomb—that is ready to light up the moment a certain ion (typically calcium) becomes present. They can even choose the intensity and color of the lights. The figure below illustrates shrimp bioluminescence which is essentially just bioluminescence in a shrimp. The blue figure depicts the photothreptin in the presence of an ion.

Written by: Vishal Agarwal Keshav Dalmia Hem Jhunjhunwala Aryan Jayanty

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Through its relation, or rather resemblance, to astrophysical concepts, we know that sonoluminescence has wide ranging aspects. These aspects are not only limited to astrophysics, but are interestingly enough also related tomarine life. An engrossing phenomenon called bioluminescence occurs in living organisms. It is defined as the production and emission of light by a living organism: when a living organism, for instance, a pistol shrimp, knocks its pray down by slamming its claws shut at such an extreme velocity that the light and heat released is said to resemble a sonoluminescent bubble (and thus, also black hole radiations!!).This occurs through a chemical reaction which occurs inside the body of the organism. For a reaction to occur, a species must contain luciferin, a molecule that produces light when it reacts with oxygen. There are different types of luciferin, which vary depending on the animal hosting the reaction. Many organisms also produce the catalyst luciferase, which help to speed up the reaction.

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PERFORMANCE SECTION

HOW DOES YOUR CAR WORK ? WRITTEN BY RITHVIK CHANDRA PAPANI Automobiles are among the most necessary technologies required for the functioning of our modern society. From the bus that takes you to school to the truck delivering shipments across the country, automobiles drive the world around us, and they have come a long way since the first automobiles created by Karl Benz in 1886. So how do cars really work? Itâ&#x20AC;&#x2122;s simple. An engine that turns around wheels. But how does that engine work? Letâ&#x20AC;&#x2122;s explore the working of the internal combustion engine.

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So, what is it that can make a few tons of metal on wheels move around? The answer is the engine. More specifically, controlled explosions facilitated by the engine which turn chemical energy into mechanical energy. But this is a superficial explanation. What really goes on behind the hood? Let’s find out.

The Slider-Crank Mechanism: As stated previously, an engine works on the principle of converting an explosion into motion, namely rotational motion. How is it then that an explosion that propagates in all directions can be controlled to turn the wheels of a car? The answer to this is the Slider-Crank Mechanism. The parts of this system include: -Piston: A small metallic cylinder -Connecting rod: A rod that connects to the cylinder -Crankshaft: A mechanical part that can covert linear motion into rotational motion, or in this case, turns the piston’s up-down motion into the rolling of the car’s wheels -Cylinder: A case which encloses all the other parts When the piston is pushed down, the connecting rod that it’s attached to it pushes down on the crank which rotates. The piston, later, goes back up due to the inertia of the crank and is ready to be pushed down again, either due to another explosion or the inertia possessed by

the

rotating

crank.

The

cylinder, in which this entire process takes place in, prevents the piston from rotating about the crank

The Four Stroke Cycle consists of four steps or ‘strokes’: The Intake Stroke- The piston moves downward, thereby lowering the pressure of the airspace in the cylinder to create a vacuum. Simultaneously due to a process that will be discussed later in the article, the intake valve opens up and thus a large amount of air fills up the vacuum created by the piston moving down. It is also at this stroke when the fuel injector sprays a small amount of fuel into the airspace. The Compression Stroke- The piston moves upwards due to the inertia of the rotating crank. This causes the piston to compress the airspace recently filled up with air. This causes the pressure and temperature of this gas to rise tremendously. The Power Stroke- When the piston is at the top of the cylinder and the air in the cylinder is maximally compressed, the spark plug ignites the air-fuel mixture and thus causes an explosion to occur. This pushes the piston downwards. The Exhaust Stroke- The piston moves upwards due to the inertia of the crank which was provided angular momentum by the explosion that occurred in the power stroke. The exhaust valve is open during this stroke and so as the piston moves upwards, the combusted gas filling up the airspace is expelled. Now, you might be wondering how the piston was able to move downwards in the first stroke.

due to gravity.

Where did the energy for the motion come from?

The Four Stroke Cycle:

preceding cycle. Hle of powering the starter

Now that we’ve covered how the linear motion provided by the explosion is converted into rotational motion, let’s explore the process by which gasoline is converted into linear motionthe Four Stroke Cycle.

It came from the explosion that occurred in the engine.

Hence, the explosion in the power stroke is the only source of energy for the piston to move and the other strokes occur due to the inertia of the crank. But this begs the question, how is the first cycle initiated? The answer to this is the starting motor which starts the very first intake stroke by turning the crank around with the power of a battery. This is why cars have jumper cables. If the battery of a car is dead, it is unable to power the starter engine and thus start the car. Jumper cables allow for the dead car battery to be recharged and thus capable of powering the starter engine.

If you’ve been reading so far, you might’ve noticed that the way the intake valve and exhaust valve are able to be in sync with the piston system hasn’t been discussed. How exactly does the intake valve know to open up at the intake stroke to let in fuel into the cylinder or how does the exhaust valve know to open up during the exhaust stroke to let the exhaust out? The answer to that is the camshaft. The camshaft is a cylinder fitted with “cams”, or lobes, placed above the cylinders which push on the valves to open them up. The camshaft is connected to the crankshaft with a chain known as the timing belt in such a way that the camshaft rotates in sync with the crankshaft such that its lobes press down on the valves of the cylinders at the right time. So, the cam shaft is connected to the crankshaft in such a way that that one of its cams goes over the intake valve during the intake stroke and its other cam goes over the other valve during the exhaust stroke. As for the timing of the ignition sparks, older models of engines used to have the ignition sparks timed to spark right after the compression stroke using the inertia and rotation of the crankshaft, much like how the camshaft times the opening and closing of the valves with the rotation of the crankshaft, but nowadays the process is automated digitally.

One thing you might have noticed is that the entire four-stroke cycle is not very smooth. The piston is at an extremely high velocity during the power stroke, directly following the ignition of the fuel in the cylinder, and at a relatively lower velocity, moving upwards against gravity, in the intake stroke. What this would mean is that your car wouldn’t have a constant speed and would instead be jittering between different velocities in a very rough manner. However, this is obviously not the case. So, how is it then that your car is able to run smoothly and with a constant velocity? The answer is multiple pistons. If instead of just one piston, there are multiple pistons working in tandem, the power is able to made significantly more stable. This is because in a multiple piston system, when one piston is at a high velocity following the combustion of fuel in the cylinder, another cylinder will be completing its intake stroke, which is much slower. Hence, the power outputs of all the cylinders are able to average out to a significantly more stable power output.

Putting this all together, you can see how an automobile fundamentally works. Granted, the engines we have now are incredibly complex and not as simple as the one described in this article, they all do follow the basic principles outlined. So, there you have it! This is how a car works.

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Putting it together

Power uniformity of an engine

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PHOTON

LASER COOLING We all know lasers can heat things up. It does this by moving particles around, which increases the particles’ kinetic energy. A higher kinetic energy means a higher temperature, so the temperature rises. But lasers can also be used to cool particles to temperatures nearing absolute zero- zero Kelvin. Atoms have discrete energy levels. This means that if an electron jumps from the second energy level to the first energy level, it must give out some energy by emitting light. This is an atom in its ‘excited state’ returning to is ‘ground state’. The atom absorbs or emits light in discrete packets called photons, which have a definite energy. Similarly, an atom in its ground state can also absorb a photon and become excited but will eventually decay back to its ground state. Since light also carries momentum, if you have light moving in one direction, and an atom moving in the opposite direction, it will slow down. However, atoms only absorb light of a specific wavelength, called the ‘transition wavelength’. The closer a light’s wavelength is to the transition wavelength, the more likely the photon will be absorbed by the atom. So, in a type of laser cooling called Doppler cooling, lasers are beamed to an atom in opposite directions. The light from the lasers have larger wavelengths than the transition wavelength of the atom, so they appear ‘redder’, since larger wavelengths are said to be red while shorter ones are said to be blue. When the atom begins to move towards a laser, it becomes ‘bluer’ and closer to the transition wavelength, while the other laser beam becomes .

‘redder’ and farther to the transition wavelength. This means that the atom is more likely to absorb photons from the beam it is travelling towards, since it is closer to the transition wavelength, which reduces the atom’s momentum, thus overall slowing it down This is happening in three dimensions, so you need six lasers to accomplish this: A much simpler, though not completely accurate, way of understanding it might be to think of the atom as a ball. If you push on that ball, it is going to absorb your energy and move in that direction. However, if your friend also pushes with the same force, but in the opposite direction, that ball will absorb both your energies, which will cancel each other out, and not move. Then imagine you have six friends, all pushing with the same force, all countering the forces of the friend opposite them. Then, the ball won’t move at all. At least, it won’t move much. So, the ball loses most of its kinetic energy, which is what defines the temperature of an object, and hence becomes ‘cooler’. Laser cooling can cool particles to temperatures as cold as 150 microkelvins. That’s 0.000150 K, which is -273.14985 degrees Celsius, or -459.66973 degrees Fahrenheit. The major breakthroughs in the 70s and 80s of using laser light for cooling led to several discoveries with temperatures just above absolute zero and improvements to preexisting technology. The cooling processes were utilised to make atomic clocks more accurate and to improve spectroscopic measurements and led to the observation of a new state of matter at ultracold temperatures. This new state of matter was the Bose– Einstein condensate, observed in 1995.

By Shrishti Kulkarni

PHOTON

PLASMA GRAPES

Okay, to understand the following explanation you first have to understand what the “refractive index” of an object is. In simple terms, it is the ratio of the velocity of light in a vacuum to its velocity in a specified medium. In addition to that, you must understand that when the frequency of a wave is constant, the wavelength of the wave is directly proportional to the velocity of the wave. All right then, now that the basics are established, let’s get on to the real stuff. Now the wavelength of the waves emitted in your microwave are about 12 cm long. Now considering that in the conditions of your microwave, the refractive index of the grape is around 10, this means that in a grape the wavelength is 1.2 cm long. Just about the size of a grape. Now if you take a whole grape without cutting it in half and place it in the microwave,

what you’ll find is that the waves get stuck inside the grape causing the grape to heat up from the center outwards. This phenomenon is comparable to total internal reflection wherein due to the high refractive index the waves reflect within the borders of the grape but a cannot escape them. Due to this, the waves actually form resonant modes, kinda like standing waves (just ways in which the electromagnetic radiation like to oscillate) such that the maximum electromagnetic fields are in the center of the grape. Now if you place another grape a little distance away from the first one, the same thing happens, both grapes heat up with the largest concentration of electromagnetic radiation in the center of each grape. But when the grapes touch each other, what happens is that maximum electromagnetic field actually occurs at the point where the two grapes come in contact. So that is where the grapes are going to get the hottest. Now with the very strong electromagnetic field at the intersection of the two grapes, what you see is some sparks, some break down of the air. That is the electric fields are strong enough that they ionize the air creating those sparks, and that is what leads to the plasma. It creates these ions which can then receive more energy from the waves emitted by the microwave. And there we have it. Plasma Grapes!

For a more in depth understanding of the phenomenon there is the link to the research referenced in the article: https://www.pnas.org/cgi/doi/10.1073/

By Mehul Gopalakrishnan

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How many states of matter are there? In your physics class, you’ve learnt about three. But in reality, there are five known states of matter: solids, liquids, gases, plasma and Bose-Einstein condensates. Let’s talk about plasma, what is it? And how does it look? Well I’ve got you covered. Here is a simple experiment you can do in the comfort of your home: Take a grape and cut it in half so that there is a small piece of the outer skin holding together the two halves of the grape. Place the cut grape in the center of your microwave making sure that the two halves remain in contact and switch on the microwave for about two minutes. Now observe the grape carefully. You should see sparks shooting out from the place the two halves of the grape are connected. That my friend is plasma. This phenomenon has baffled scientists for years. Why does a grape, a simple grape, when microwaved, form plasma? Recently three scientists analysed this phenomenon with state of the art technology and published an article in the Proceedings of the National Academy of Sciences containing their findings. And their findings are interesting.

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PHOTON

INTO THE 2D BACK AGAIN Recent research at the Australian National University has revealed a number of 2D materials that could potentially withstand the extreme conditions of outer space. The study was led by Tobias Vogl, who was particularly interested in the endurance of 2D materials against radiation. The space environment is vastly different from the environment on Earth, so the materials were exposed to levels of radiation comparable to those expected in space. Any object in space has to deal with 2 major changing factors: temperature and radiation. While these 2D materials have been shown to be extremely effective in withstanding temperature fluctuations, little could be said for their endurance of radiation until now. The ANU team simulated some potential orbits to model the radiation that the materials would probably be exposed to in space. When testing these 2D materials, the team “didn’t see much difference” in their optical and electrical properties. The materials tested were graphene and transition metal dichalcogenides of the form MX2 (M: Molybdenum, Tungsten and X: Sulfur, Selenium). Most of these materials “coped well” when exposed to radiation. One material in particular, tungsten disulfide, yielded surprising results under the gamma ray test. Tungsten disulfide actually increased in performance with an increase in gamma radiation. Even with gamma radiations far exceeding the expected radiation in space, tungsten disulfide the material became “better” and “brighter.” Vogl even said that the material reminded him of “the Hulk.” According to the team, tungsten disulfide could be used not just in space, but even on Earth, to detect radiation levels in harsh environments like nuclear reactor sites.

By Yash Panjawani

The 2D objects used in the study could be used to constructs sturdy satellite structures. Graphene would be a strong candidate for this application, as it is 5 times stiffer than steel. The materials could also be used to make lighter and more efficient solar cells, which would significantly decrease the cost of launching space missions and would make them more accessible.

The research has been published in the journal Nature Communications

PUZZLES: A large ship moored at the dock has a rope ladder hanging over its side all the way into the water. Its steps are 30 cm apart, and 20 steps are above the water. The tide comes in at the rate of 15 cm/hour. After 6 hours how many steps are above water? Student A and Student B are doing a lab experiment, measuring friction by timing wooden blocks sliding down an inclined plane at constant speeds. The blocks measure 3 x 4 x 5 inches. Student A suggests a race, and predicts that if a block is sliding on its 3x4 face it will have smaller contact area and smaller friction than if the block is sliding on its 4x5 inch face, so with smaller frictional drag it will win the race when both slide down the plane. Student B disagrees, arguing that they still weigh the same, so the race will end in a tie. Who is right, and why? Submit your asnwers to guparyan@tisb.ac.in or gaaditya @tisb.ac.in

PHOTON

THE JOURNEY OF CREATING THE WORLD’S FIRST ‘PERFECT MIRROR’ We are all familiar with objects called mirrors. Be it

At most of the angles, the light was partially

bathrooms, bedrooms or vehicles, we can’t imagine

absorbed by the lattice structure, but with a specific

our lives without mirrors. Imagine living your life

wavelength and at a specific angle, light was

without knowing how you look! Mirrors are an

perfectly reflected. Every photon that was emitted

intricate part of our lives. However, a lesser known

by the red-light source was perfectly bounced

fact is that mirrors that are commonly used do not

back, at exactly the right angle, with no absorption

reflect all the light that falls on them.

or scattering.

These conventional mirrors work in a simple

This phenomenon caught the world by storm and

manner: they block the passage of light (or sound,

was believed to be one of the most impactful

or water, or radio waves), and so they have no

discoveries made in material science. Scientists

choice but to reflect the energy incident on

exclaimed

them. Such mirrors are basically transparent glass

application in various places, especially research in

with one side painted with a grey, lustrous material

physics and engineering. Such perfect mirrors

such as silver. Intuitively, we can imagine the fact

could be used for powerful and effective lasers, but

that not all the energy will be reflected as some will

concentrated solar power (using mirrors to boil

be absorbed, owing to the nature of the

water), and fibre optics could also be

material. For a human checking their hair or

improved.

makeup, this lack of perfection wouldn’t matter; but

applications for these perfect mirrors, the MIT team

when you talk about reflecting lasers down a

focused on finding out exactly what took place in

hundred miles of optic fibre, or installing solar

this phenomenon. This question is yet to be

powers, these tiny imperfections cause a huge drop

answered and scientists are working day and night

in efficiency.

to understand this amazing case.

In 1998, an accident by quantum physicists

In conclusion, these perfect mirrors were

working at MIT, proved to be the perfect solution

something we didn’t know we needed until we

for the problem of incomplete reflection. The team,

came across it (by sheer accident, of course). Also,

led by Marin Soljačić, was studying the behaviour of

not only do such mirrors reflect light, they reflect all

a photonics crystal that consisted of holes drilled

kinds of waves, including sound and heat

into it, hence, forming a lattice. These holes were

waves. These in turn would prove to be extremely

extremely tiny, in fact so small that they could

beneficial for physicists and engineers alike. And

accommodate only a single light wave.

who wouldn’t want an invisibility cloak?

discovery

While

have

enormous

having plenty of practical

By Pratyush Sahu

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this

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IS A BOLT OF LIGHTNING HOTTER THAN THE SUN? by Arsh Vohra A bolt of lightning can reach up to temperatures of 30,000 kelvins. On the other hand, the surface of the sun is just 6000 kelvins. This seems to be an open and shut case. According to these facts a bolt of lightning is hotter than the sun but there is much more to this than these two simple figures. It is important to note that the surface of the sun is the coolest layer and cannot be considered as the entire sun. As we go deeper towards the core of the sun, plasma temperatures of fifteen million kelvin can be sited. In comparison it is not the hottest temperature plasma has been sighted at but is much hotter than a lightning bolt. The electricity of the bolt does not have a temperature as heat is only produced when electricity flows through the air. As air is a good insulator of heat so it does not allow heat and electricity pass easily so there is a lot of resistance. This is also the reason why people can survive being struck by lightning. There is lesser resistance when someone is struck by lightning keeping the person relatively cooler.

Another key factor is time lightning only strikes for around ten microseconds. Which is an extremely short period of time and it is impossible for the total energy to be equal to that of the sun. If a strike of longer time was to stay for a longer time it would be fatal if anyone was to be struck by lightning. All in all it would be false to say that a lightning bolt is hotter than the sun but a bolt can reach higher temperatures than that of the surface of the sun.

References: https://www.seeker.com/is-lightning-hotter-thanthe-sun-1765058578.html https://www.dcu.ie/ncpst/about/what-is-plasma.shtml https://www.weather.gov/safety/lightning-temperature https://www.sciencealert.com/5-things-about-lightning-we-allneed-to-remember https://www.reddit.com/r/explainlikeimfive/comments/2essno/eli 5_if_lightning_is_hotter_than_the_sun_then_how/

DID YOU KNOW

High energy molecules leave boiling liquids, reducing the temperature of the remaining liquid and making it freeze under specific conditions

If all the matter that made up the human race were to be compressed, it would be no larger than a sugar cube, as atoms are 99.9999999999999 percent empty. This can be observed in a neutron star as well, as it is one of the densest objects in the universe.

By Aanya Pratapneni

Imagine that a scientist from the future travels twenty years back in time and tells you how to make a time machine. You then proceed to follow the instructions and successfully create a time machine after twenty years. The scientist then goes back in time to tell the earlier version of you exactly how you made the References: https://www.seeker.com/is-lightning-hotter-thanmachine. The question now arises – who the-sun-1765058578.html figured out how to create the time https://www.dcu.ie/ncpst/about/what-is-plasma.shtml machine? This phenomenon is commonly referred to as the ‘Bootstrap Paradox’. https://www.weather.gov/safety/lightning-temperature Here’s a fun video that might help you https://www.sciencealert.com/5-things-about-lightning-we-allunderstand: need-to-remember

https://www.youtube.com/watch? https://www.reddit.com/r/explainlikeimfive/comments/2essno/eli v=u4SEDzynMiQ 5_if_lightning_is_hotter_than_the_sun_then_how/

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Water can boil and freeze at the same time – This occurs when the temperature and pressure is just right and is known as the ‘triple point’.

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HOW TO COOK A CHICKEN WITH PHYSICS Imagine the stress of cooking for a family, a stress which many people go through every day. There is often lots of patience and vigilance required when traditionally cooking, especially when heating meats on a stove. But what if instead of spending minutes waiting for your chicken to fry, you could just slap it once and be done with it. Well that future may not be too far off, and today we will explore the requirements for that scenario.

We will be considering the objective requirements to cook the average chicken breast to a safely eatable level, all biological values used (i.e. Weight of chicken) are global averages.

The primary method of heating our chicken will be slapping it with our hand, and as we now know the energy needed, we can now find out the minimum velocity of our hand. The energy of a moving object is called kinetic energy (K.E.) and is given by the formula K.E = 1/2(mv^2) where m is the mass of the object in kilograms and v is the velocity in meters per second (m/s). and then plug in energy and mass to get the velocity squared. The average human weighs 70 kg and on average the human hand is 0.58% of the total body-weight, giving us an average of 406 g for the hand however as the equation is in kg we must use 0.406 kg. Apart from that, we already know the required K.E. to be 34 KJ so when we plug those values into the equation, we get 167487. As that value is velocity squared we must then take the square root of 167487 to get velocity, which is 409.25 m/s. Therefore, on average we must slap the chicken at 409.25 m/s or 1473.7 kilometers per hour to cook it, for reference the speed of sound is 1224 kilometers per hour which is much smaller than this. However, before you go and slap chicken at the speed of sound, there is one assumption throughout this entire article. We are assuming that all the energy in our slap will be converted to heat energy in the chicken upon impact. In reality this is far from the truth with only a small fraction of our hand’s kinetic energy being converted to actual heat, so the actual value would be much larger than this. Finally to conclude, all the values taken in this scenario are global averages, as we are dealing with biological will needhere to adapt systems you these values to you own scenario (i.e. Weight of chicken or mass of hand). As such the author of this article is not responsible for any food poisoning caused by following the procedure mentioned throughout.

Rishi S Papani

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Our chicken breast will be starting at room temperature or 25°C and the minimum temperature to cook chicken breast is 74°C, so we will have to heat our chicken by 49°C in order to safely eat it. To find the energy required to heat our chicken by 49°C we will have to use specific heat, specific heat is the energy required to change the temperature of an object by 1°C. However, specific heat varies from substance to substance and as such the chemical makeup of our chicken is needed. Apart from that, we also need to know the mass our chicken, as heavier objects need more energy to heat up more particles. Chicken breasts on average weigh anywhere from 170 to 226 grams, for the sake of this calculation we will be taking the average of that which is 198g, and its chemical composition is 75% water and 24% protein by mass. This means that 75% percent of our chicken’s mass is water, or 148.5g, and 24% of its mass is protein, or 47.52g. The specific heat capacity of water is 4.2 joules(J) per gram(g) per °C, this means to raise 1g of water by 1°C we need to supply 4.2J of energy. As we have 148.2g of water we will need to multiply our specific heat by 148.2 this gives us 620J, meaning that we need 620J to heat up the water in our chicken by 1°C. The approximate average specific heat of protein is 1.7J per g per °C, as we have 47.52g of protein we will therefore need 72.7J to heat up the protein in our chicken by 1°C. We can add both of these values to get the energy needed to heat our chicken by 1°C, 72.2J + 620J = 692.2J, meaning that we must supply 692.2J to heat up our whole chicken by 1°C. Lastly, we need to heat our chicken by 49°C, this means that we will be heating up our chicken by 1°C 49 times, so we will need 49 times the energy (692.2 * 49) which is 34KJ or 34 thousand joules to cook our chicken.

An Insight into

Non-Newtonian Fluids You must be wondering what are Non Newtonian fluids and how they are different from Newtonian Fluids like water. In this article, we will discuss about the different types of NonNewtonian fluids and how they differ from water. First, let me introduce you to the term viscosity. Viscosity is the measure of resistance of a fluid to shear stress or tensile stress. In liquids, this is simply observed as the “thickness” of the liquid or the ease of flow when it is poured. The easier it is for the solution to flow, the less viscose that fluid is

considered to be , but solutions like ketchup have a higher viscosity (does not flow easily when poured out). Isaac Newton described that normal fluids will have a constant velocity coefficient as the force or the shear stress applied on the solution increases. The only way to change the viscosity of the fluid is by means of temperature. An example will be water that turns into a solid at 0˚C and a gas at 100˚C. In between this temperature range, the water will be a liquid with constant viscosity.

Non- Newtonian fluids on the other hand, like oobleck and ketchup do not obey such properties. Oobleck and ketchup do not tend to have a constant viscosity co-efficient with a change in the shear stress applied on the fluid. However, the change in viscosity as the stress is applied varies on the Non- Newtonian Fluids being considered. The change in viscosity is related to two factors, being the sudden stress applied on the fluid (non Newtonian viscosity) and the stress applied on the fluid over a period of time (time dependent viscosity).

Different types of Non-Newtonian fluids: Time-dependent properties (Thixotropic and Rheopectic) Thixotropic: These liquids decrease in viscosity as the stress applied on the solution increases over time. These fluids become runnier if I apply stress on it for a longer period of time. An example of this fluid is honey, where as you keep on stirring honey, the solid honey becomes a liquid as its viscosity reduces over a period of time. Rheopectic: These liquids are the exact opposite of thixotropic, where the liquids increase in viscosity as the stress applied over time increases. This means if I apply a force to such fluids over a longer period of time, this causes the liquids to become thicker and behave like a solid rather than a liquid. An example of this fluid is whipped cream, because the longer you whip it, the thicker it gets.

Pseudoplastic/ Shear Thinning: For such fluids, the viscosity of the fluid decreases with increased stress.

The difference between this fluid and thixotropic fluids are that the stress applied on pseudoplastic fluids is sudden and does not act over a period of time. An example of this liquid is tomato sauce. If we turn over the tomato bottle the sauce does not come out, unless we apply some force or stress to it which causes the tomato sauce to behave like a fluid and come out on your plate. Dilatant fluids/Shear thickening: For such fluids, the viscosity increases with increased amount of sudden stress, not stress over a period of time differentiating it from rheopectic fluids. An example of this fluid is oobleck (a mixture of cornstarch and water). In such fluids, people can walk over it, jump on it causing the fluid to change into a solid, resisting the personâ&#x20AC;&#x2122;s body from sinking in to the fluid. However, as you stand over a pool of oobleck for a long period of time the water molecules come closer together, restoring the original state of oobleck and like quicksand, you end up sinking inside this fluid.

The physics of Non-Newtonian fluids So, what causes these liquids to behave as a solid in one instant when the stress is applied on the object, but behave as a liquid the moment the stress is not applied? What causes these liquids to behave like a quicksand? Well, this will be considered by taking the example of oobleck , a dilatant liquid that is a suspension of solid (starch) particles in water. Cornstarch are large molecules, whereas water are smaller particles. When these two particles are added together, a suspension is formed where each cornstarch molecule is surrounded by water molecules. In the event of weak stress, a little bit of force is applied on the cornstarch molecules, but they are able to slide past each other as they can pass over the water molecules. In the event of a large force or stress applied on the fluid, the water molecules are pushed out from in between the corn-starch molecules, creates an area full of corn starch molecules on the surface of the liquid. For a suspension to behave as a Non-Newtonian fluid, the ratio of corn starch molecules to water molecules need to be within a certain range. If there are too many water molecules, then the suspension will behave as a liquid, but if there are more cornstarch molecules, then the suspension behaves as a solid as there are not enough water molecules between the corn-starch molecules for them to slide past each other. Hence, applying a larger stress on the fluid results in a larger cornstarch molecule concentration on the surface, making it seem that your hand has hit a solid,

but applying a weak force results gives time for the cornstarch molecules to slide past the water molecules, therefore resulting in a suspension acting as a liquid. This explains the fact that when you squeeze a handful of the oobleck and roll it into the ball, the cornstarch molecules comes closer together and traps the water between them, resulting in a solid. On the other hand, as you release the stress or free your hand, the water fills in the spaces between the cornstarch molecules resulting in the suspension to behave as a liquid again. Application These properties of Newtonian fluids are used in painting walls of your house. The paint flows readily off the brush when it is applied to surface being painted, but does not drip excessively behaving as a thixotropic fluid. These fluids also have future applications in body armor. Such fluids are flexible, allowing the soldiers to move freely but when under attack or stress, the material will quickly harden performing like the traditional armor. It can also offer a flexible basis to constructed structures or buildings in earthquake-prone regions minimizing the effect of vibrations on the constructions in the course of an earthquake. Even when your bathing, shampoo is considered to be a NonNewtonian fluid that only flows when a stress is applied on the bottle, allowing it to flow readily on your hand to be applied for washing your hair. From brushing your teeth, the toothpaste used is a NonNewtonian fluid. Even when it comes to eating your food, ketchup and custard are considered Non-Newtonian fluids. By Ansh Bhatia

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Why science teachers should not be given playground duty

JOKES! compiled by Vikhyath MondretiÂ and Aditya Gaur

I'm not lazy, I'm just overflowing with potential energy

Professor: Does anyone have any questions before the tomorrow's exam? Student: Can you go over terminal velocity? Professor: No.

Status Update SNAPSHOTS:

Aryan Gupta Editor

Accomplishing what was antecedently thought to be not possible, a team of astronomers has captured a picture of a black hole . proof of the existence of black holes – mysterious places in space where nothing, not even light, can escape – has existed for quite some time, and astronomers have long observed the results on the surroundings of these phenomena. it was thought that capturing a picture of a black hole was not possible as a result of an image of something from which no light would appear escape would seem completely black. For scientists, the challenge was how, from thousands or even several light-years away, to capture a picture of the hot, glowing gas falling into a black hole. an ambitious team of astronomers and computer scientists has managed to accomplish both. working for well over a decade to achieve the accomplishment, the team improved upon an existing astronomy technique for high-resolution imaging and used it to find the silhouette of a black hole – outlined by the glowing gas that surrounds its event horizon, the point beyond that light cannot escape. this will not only help us to improve our knowledge regarding black holes but also understand gravity like never before.

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