Sunday, 1 February 2015

Natural Questions with Unnatural Answers!

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Good Morning! A new day again! I got up by quarter to 6 AM and after some physical exercise I sat searching the net. Now, as it's obvious to get questions round your mind all the time; I hit upon the and soon I came across a plethora of unanswered question stuck across the page… I got interested with the nature of the questions so, I decided to look at the science questions and the first question peeking at me was "Where was science invented?" Now such questions are obviously good for your health for it lets you laugh at least 15 minutes and we everyone know the benefits of laughter…
But after humor, as it always happens, philosophy starts pouring in and I really wondered about the person asking that question… may be crazy… or he may be pretending to know the answer. We know that invention needs an inventor and the obvious question that follows is “was science invented” and who then is its inventor. The common folks would say its Archimedes or Galileo less informed ones may extol Einstein but question is did they invent science? Obviously not, inertia or gravity existed long before Galileo or Newton had discovered it. And if the fundamental constants of physics like Planck’s Constant, Velocity of Light, Charge of electron, etc, would vary even by one millionth of its present value universe as it is would not have been possible!… err…wiping out the possibility of me writing a blog in this mid noon as well. Nevertheless, things had worked out perfectly and the constants were affixed appropriate values or in technical words were “fine tuned” to keep us happy. Now physicists are on their usual rat race for churning out the answers out of some bizarre mathematics of what they call “string theories” (for your information this string has already died in the hands of a membrane). They have speculated that geometries of space may be the reason behind the constants and have consoled us telling that we live in one of the most probable universes; which has got no experimental backups! Well, it is said too much philosophies spoil the broth! But the question made me think…

The next candidate was enough challenging it came with a straight face “How did Edwin Hubble Change the World?” Now, interestingly the sun rises from the east before and after Hubble; positions of the galaxies and stars have not altered since then, neither had he turned the world into a sci-fi mumbo jumbo. Well, microscopically he had added a few more entropy like every living system does (in that respect he hasn’t changed the world more than a hippo or the bacteria) perhaps with a few more additions to the global population kitty. Yet he had changed the world and he changed it almost completely. He is credited with demonstrating the first flaw in Einstein’s General Relativity Field Equations which Einstein had himself admitted as the biggest blunder of his life.

Well, so what did Hubble actually do? To understand his discovery let us take the example of a whistling train (hey brat how whistling train jumps into our cosmological discussion…hold your breath soon you’ll get to know). Did you ever notice that a whistling train running towards you? You may have observed that its shrillness increases or if it recedes away its shrillness decreases. That is the frequency of the sound depends upon the relative velocity of the train and you (i.e. source and observer), it increases if the source moves towards the observer and decreases if it recedes away.

This is called Doppler Effect in sound. Similar effect is noticed in case of light waves too with a little modification, known as Doppler Effect in light. Now as shrillness is an effect of frequency in sound similarly color is the effect of frequency in light waves. So if a light source moves away from us we must observe decrease in frequency of the light.
This is the Electromagnetic Spectrum (it is the broader classification of waves that contains light waves. 
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Saturday, 28 May 2011

Of Waves, Physics and Tsunami

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6 hours has already been over and we are breathlessly waiting for that ruthless wave and Goofy is busy making plans for surfing the wave, err…to Goof up with his life this time and letting him know of the Physics behind Tsunami seems the only way to deter him from surfing the Tsunami.

Goofy: “Tsunami is a water wave right? Water waves that I have surfed for at least 15 years now… What’s the difference?... The difference exists only in name?”

Me: “Not at all, as I have already told you Tsunami is a water wave that is formed due to displacement of a large amount of water. Such voluminous displacement is generally effected by an underwater earthquake, landslides or meteorite impacts.

The expected Tsunami for which we are on high alert is due to an underwater earthquake of magnitude 9. So let’s look into the details of Tsunamis generated by earthquakes.

Everything begin with energy, we walk, talk, jump, air flows, strings vibrate, waves occur… all are but manifestation of energy. Recall the string experiment you have performed with Jane… remember you had to use your energy to produce waves in the string? 

Goofy: “Yep, I do.”

Me: “So if Tsunami is a wave there must be an energy source to let it happen. Yes, this energy is provided by the earthquake.

Cause of Earthquake

Fig. 1. Earth's Crust and Plates
Earth has got hot magma inside and the solid crust where we live is actually composed of various “plates” which happen to float on the liquid magma ocean. The boundaries of plates are active volcanic activity sites. Activities of magma like contraction due to cooling, percolation of water into the hot zone etc, builds up of pressure within the rocks leading to movement of the various plates. The plates collide and pressure keeps on mounting in the rock strata. See the figure.

Now Earthquake takes place because of building up of such pressure (stress) within the rock strata inside the earth’s crust until they are deformed (strained) to a point (breaking stress) beyond which they would break causing a mass movement and release of a tremendous energy (shown by the blast symbol in the diagram).

The Point at which such break occurs is called the focus which is inside the crust and the point just above the focus on the surface of the earth is known as the epicenter.  See the diagram.   

Now Tsunami is a vast subject, so let us divide its study into two broad parts
1. Formation of Tsunami
            1.1. Energy of Earthquake and Tsunami.
            1.2. Comparative Energy Output Study.
2. Propagation of Tsunami
            2.1. The Restoring force and Gravity waves
            2.2. Tsunami in Deep, Intermediate and Shallow waters
            2.3. Wave Shoaling Process and destruction.
            2.4. Linear Wave Theory. 

Fig. 2. Tsunami Formation

1. Formation of Tsunami

When an earthquake occur underwater tremendous amount of energy is released between the plates, this energy (most intense at the epicenter) may be released in lot of forms like heat generated between the strata, sound energy, displacement of land mass etc, but a part of this energy is associated in giving a specific upthrust (force) to the water column above the sea bed causing a displacement of the water column. This initial lump of water displaced is sometimes called “Waterberg” in analogy with iceberg.

Since this actually is a mass of water raised to a height h (see the figure) against the gravitational force of earth, potential energy (mgh) is built up. This energy is transmitted via ocean waves known as Tsunami.”

Goofy: “How great is that energy? I mean it seems too low for a Waterberg to cause such a massive destruction to the coasts which is even impossible for some greatest storms too.”

Me: “Okay very nice question Goof  

So you must be quite unaware of the amount of energy released by an earthquake. Let us see to it…

(To be continued…)

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Monday, 2 May 2011

Of Waves, Physics and Tsunami

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“Hee Haw!” Enters Goofy Crackedjaw… He must have made an adventure with his surf-boat today.
“Hey guys! Dare to surf a 40 feet giant wave? None of you have that damned guts.”
Jane: “How stupid! I look better with my jaws intact rather than to have odd guts to sacrifice it for a poor wave.”  
Goofy had his jaws cracked when he was tossed into a shore rock riding a big wave… he is a talented surfer but sometimes he underestimates the power of a wave and overestimates his skills. So we call him Crackedjaw Goofy.

Goofy: “You’ll never get that ‘out of earth’ experience ‘messedup Jane’… what you cooked today cockroaches for chicken?”

Oh yes! Jane is a girl of 18, she studies physics and known for making mess in the kitchen, in the market place… as her mom says “she has always been so nice, talented… err… but messy, like once she had poured gasoline in the flower tubs and water in the car!”

Jane: “You’ll have to pay for your sins Goofy; I warn you, don’t jeer at me that way.”
Me: “Guys stop fighting; I have got news for you mates”
Jane: “Hey what’s that… Has another Goofy died surfing a wave?”
Me: “Come-on Jane, spare him now… Do you know our coasts are on high alert for Tsunami? Forecasters are expecting a tsunami within 12 hours.”  
Goofy: “Hey Jane I’ll mark a new world record surfing the Tsunami… it’s your last chance to meet a celeb Jane. I’m ready with my boat let that tsunami come”
Me: “Beware Goofy! This time you may Goof up with your life … It is not a wave that can be surfed, we must move highlands for safety.”
Goofy: “Well, I’ve surfed giant waves taller than a 5 storey building… and what the hell is tsunami?…”

Me: Tsunami is a wave.

What is Tsunami?

Tsunami is a water wave that is formed due to displacement of a large amount of water. Such voluminous displacement is generally affected by an underwater earthquake, landslides or meteorite impacts.

Well, for Jane such definitions won’t work as she likes more formal definitions so to put it for her: A tsunami is a shallow water gravity wave that has a large wavelength and small amplitudes in deep water, however, as the wave moves to shallow water the speed of the wave decreases and its amplitude increases tremendously.

Behavior of these waves is greatly different from the wind waves or the normal sea waves that surfers usually encounter.   

Jane: “I see, this definition sounds familiar; I have read about water waves in deep seas and their behavior in the shallow water. They are mostly non-linear waves.” 

Goofy: “Big Words! So what the hell I’m doing here it is better I wait for the high waters in the sea.”

Me: “Hey Jane don’t go that deep coz you know our good friend Goofy is a surfer…he likes to stay on the surface… and big words make him sink… :D”

Goofy: “Not like that… I am interested in learning stuffs provided they be put in plain… not like Jane’s geeky words. Okay, now what causes Tsunami, how do they propagate and how are they dangerous”

Me: “Good questions Goof… well first you must know what a wave is… that is physicist’s wave”

Goofy: “Ok what actually is a wave then?”

Me: “A wave is a periodic disturbance. That means the motion/disturbance would repeat itself after an interval of time.” 

Even a child knows how to draw a wave, the difference between physicist’s wave and a child’s wave is: physicists give the waves and its parts some names (known as wave profile) and they try to relate the various parts mathematically for calculation purposes; that makes it appear alien. 

Quantities like wave length, Amplitude or the maximum wave height, frequency or the number of vibrations made in 1 second, phase etc are called wave profile.” 
A Physicist’s wave:

Goofy: “I see, it’s so simple… I am gonna read all of Jane’s books”
Jane: “Someone had rightly said ‘A little knowledge is a dangerous thing’”

Me: “Guys calm down. Well, let’s see how a wave is generated… so that we can understand the mechanism of Tsunami generation. Goof and Jane hold on the ends of this 5 meter string, and then one of you shake it up and down… what can you see?”

Goofy: “Yoo! I can see a wave in the string moving towards Jane.”

Jane: “Goofy can you say what is moving towards me here?”

Goofy: “I am not a retard not to know the answer for such kinky questions.”

Me: “Goof! Answer her; this would let you know a lot about waves.”

Goofy: “KK, simple the wave is moving I can’t see any other objects to be moving towards Jane… do I? Yep, I can see the string move vertically up and down”  

Me: “Great, a good observation from Goofy, the particles of string are moving up and down but are not moving forward towards Jane. This means particles of the medium (here it is string) under the influence of the wave don’t move forward with the wave. Thus, what moves through the wave is the energy.”

Goofy: “Energy?”

Me: “Yes, energy, the ability to do work… see you have got the ability to move the string up and down this is evident as your hand is moving up and down but can you see this up and down motion has reached at Jane’s end of the string, thus your ability of making the string move up and down or doing the work is being transferred at Jane’s end of the string via waves. Thus, waves transfer energy.”  

Goofy: “I see; it’s simple.” (Jane Frowns)

Me: “Ok Goof, just match the waves in the string with the physicist’s wave and try to identify the wave profile: amplitude, wavelength, frequency. And draw them on a paper.”

Goofy: “I have got a question…well it seems that waves don’t carry the particles of the medium along with it… but from my experience as a surfer quite a lot of times I have seen waves to carry a good deal of water forward with it. How would you explain this?”

Jane: “It’s simple… okay have you seen the water brought by the waves recedes away with the wave too? A sea wave is a lot more complicated than string wave… in string the particles of the string are seen moving up and down that is moving perpendicular to the direction of motion. But in sea waves the particles of motion move in circles or ellipses, that is you may say it is a combination of vertical up and down movement with horizontal to and fro movement. So we can see sea waves moving up and down and still brings water with it.”

Me: “Exactly, but it is also possible that the particles of motion never get back to the actual positions after course of the wave… These are non linear waves… a bit complicated for you to learn just now Goof.” 

Goofy: “Okay! So it needs a good deal of knowledge to understand Tsunamis.”

Me: “Yes, because water waves are far more complicated than other forms of waves like light etc.”

Jane: “So Goofy drop your idea for surfing Tsunami of which you don’t know at all.”

Goofy: “Okay as you say.”

 He heard to her for the first time.

To be continued…
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Tuesday, 29 March 2011

Kitchen Physics And The World Around Us

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       In the last blog you must have met with our “peaceful” Dragon. She loves cooking but she is bothered all the time by the failing appliances of her kitchen that I have to mend  always (poor me) and I let her know of the kitchen physics that keeps me safe:D.

Me: "Good Morning Dragon! Is everything okay?"
Dragon: “Yup
Me: “It seems you are in a hurry. What’s up?
Dragon: “I am late and I’ll have to reach office soon and today everything was so messed up plus I suffered an electric shock
Me: “Aw, why? What messed up?
Dragon: “My water heater, I shouldn’t have used this old wicked thing.
Me: “Okay I’ll see to it but why are you stirring your nonstick pan so vigorously with steel spoon, it might damage it.
Dragon: “Why non stick cookware should not be stirred with steel spoons?
Me: “See Dragon, Nonstick cookware is made of aluminum and related alloy very much like ordinary cookware, but what makes them different is the special coating of Teflon on its surface. Teflon is a polymer and not metal which is very stable towards high temperature and it gives the cookware the property of non stickiness.
If nonstick cookware be stirred with steel spoons, steel being harder than Teflon puts scratches on it and with time the Teflon coating wears away thus the “non stick” property of the nonstick goes and it becomes useless."
Dragon: "Um okay, but how is hardness related to the scratches made?"
Me: "Good question Dragon; a hard substance can produce scratches on a soft substance. Let us for example take the instance of our finger nails and wax…can you tell me which one is harder?"
Dragon: “Obviously our finger nail; mine is harder than yours though.
(Dragon smiled victoriously). 
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Saturday, 19 March 2011

Physics in Dragon's Kitchen

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 Tomatoes, Potatoes, Oils in Kitchen, sound fine, Now what about Physics in kitchen. (This blogger must have gone crazy, he takes oven for a nuclear reactor!) Nope, I am not crazy and yes there is kitchen physics along with kitchen chemistry; Although, the later is far more popular. Now, let us turn our attention towards the Big Boss in Kitchen (She is no ordinary human being but a full fledged yet "peaceful" Dragon ) ...And what she has to tell us about Kitchen Physics.

Me: "Hey Dragon! it's late afternoon what are you innovating there there so something special delicacy is to be prepared?"   

Dragon: "Yes! delicacies are being prepared, but hey I am getting difficulties with my kitchen appliances that keep on failing all the time."

Me: "They must be scared of you lolz, why what's up?"

Dragon: "See this time my gas lighter has failed, I wonder why... perhaps it's battery has gone out"  

Me: "Lemme look at the lighter you've got... Lol your lighter don't need batteries, Now can you tell me  how electric sparks are generated even if there is no batteries there"

Dragon: "Because I am standing near it!! DUH"
Just look at her simplicity, she thinks it works because she is near, may be she thinks there's some hmmm factor.

Then, I tried to explain her the Kitchen Physics about the lighter

Me: "See Dragon, many of us don't know that the electric sparks made by portable gas lighters are not driven by batteries. A peculiar principle of physics is associated with it, it is known as "piezoelectric property". What happens is, by the virtue of piezoelectric property some crystals like quartz tend to develop a voltage across it when it is deformed by mechanical pressure. Now such voltages can really be very high like in the order of thousands of volts.  In the piezoelectric-ignition lighters a spring hammer is used to strike a quartz crystal which results in a sudden deformation of the crystal followed by a voltage of several thousand volts, this is then led to the spark knobs by connecting wires and we get sparks.

Look at its internal construction to know it better"
Dragon :"I've understood a lot"
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