sciencecapsules

    When a child reads a book, he adds letter by letter and form words; collects words together and make a sentence; goes through sentence by sentence and completes a page.  Similarly, a picture is scanned in computer, TV, etc.,      A picture is divided into number of lines and each line is split up into number of points.  A point is called a pixel(picture element).  Hence the picture is read pixel by pixel and line by line.      Each pixel has brightness info and colour info. Each pixel's info is converted into electrical signal(voltage) then into digital form(0s and 1s).  When the whole picture is converted into electrical form or digital form, it can be stored, manipulated and transmitted using high frequency waves.             Scanning occurs in TV, camera, Computers, CAT scan , photocopier etc,. Note:  In TV. 625 lines are scanned in one picture and 25 pictures are transmitted to the TV in one second.  One line is scanned in 64 microsecond.   

        Draw a triangle.  Within that, draw  another inverted triangle.  Now we get 3 triangles in 3 corners.  Within these triangles, again draw inverted triangles.  Now repeat the procedure as many times as possible.  The emerging figure is called the sierpinski gasket.  This is the good example for self similarity.  The overall structure is replicated many times throughout the figure.  And it is even present at the microscopic level.      To put in nutshell; using self similarity technique and repeating infinite number of times, one can generate complex figures.      These figures does not fall in a straight line(one dimension) or occupy the entire area of the square (two dimension).  They fall somewhere in between dimension 1 and 2.  So they are said to be having fractional dimension.  Hence they are called FRACTALS .  Fractals occurs everywhere in nature. Examples: Trees, leaves, snowflakes, peacock feathers, seashells, lungs structures, lightnings, broccoli, ferns,

      Let a man named "A" be traveling in a train at a speed of 100 km per hour.  He is comfortably sitting in the seat no.10 of the compartment "A1".      Let another man called "B" be standing in the open field where that train is passing through.  Let us assume that the man B is having a "special instrument" using which he is able to follow the train and also able to watch what is happening in the compartment A1 in detail.      Let A toss a coin  and B watches that event from outside the train.  Now, put a question to A,  "Where you tossed the coin and where it had fallen?"  He will definitely answer like this " I have tossed the coin in this compartment A1 and it has fallen near my feet.  It has not gone anywhere else.  Why this question?"      Next, put the same question to B.  He will answer "the coin has gone up at one place but it has fallen a few meters away from the point of throw". (Since the train

Natural numbers :      To count apples and oranges, we need numbers like 1,2,3....These whole numbers are the natural numbers.  They are marked on the right side of the number line. Negative numbers :      A car runs in the north direction with the speed of 50 km per hour.  Another car travels in south direction with the same speed.  The second car is said to be running with the speed of  -50 km per hour with respect to the starting point.  So we need negative numbers like -1,-2, -3.  They are marked on the left side of the number line. Zero :      How many apples are there in the empty basket? - nothing. So, we need a symbol for nothing and that is 0 .  0 is marked in the middle of the number line separating negative and positive numbers. Rational numbers :      To share one apple among 4 people, we cut the apple into 4 pieces.  So each one get one fourth(1/4) of a apple.  So the rational numbers are those numbers which can be expressed as a ratio between two integers.

  Take a strip of paper.  Give it a half twist and paste the ends.  It will look like a some twisted loop.  This is called mobius strip.      Now take a pen and draw a line at the centre of the strip.  If you go on drawing the line, you will come and meet the starting point of the line.  This indicates that this object has only one side or surface.  That is , two surfaces have become one long surface.        Now take a scissor, start cutting in the middle of the strip.  At the end, you will not get two half loops but two loops linked like a chain.  These are some peculiar properties of a mobius strip.  But there are some applications for this strange strip.        It is used as a conveyor belt so that  both the surface will be used evenly and as a result the belt will lost longer.  In computer printer, typewriter ribbons, recording tapes, this strip is used to use both the sides efficiently.      Today, it is used in nanotechnology also.      

     We will look at "the time" in various angles in this article.      It is said, today's atomic clock measure time accurately and it may make a error of one second in 5000 years.  We know, one day is based on earth's spin and one year is based on earth's revolution around the sun.  It is again said, earth slows down slowly.  So they add a second  to"a year" every few years.      Earth is divided into number of time zones depending upon the appearance of sun at the place.  So we have a global average time called Greenwich mean time.  In space, earth's time is meaningless.  We may need a universal mean time for the future space explorers.       Place ice cube in a beaker.  The ice will slowly become water and then vaporize.  That is, the molecules become free and move randomly.  Hence the thermodynamics says, as the time progresses the disorder increases( entropy).  Some asserts that time is forward moving arrow and cannot be reversed.    

       FINANCIAL CRISIS :     The following formula calculates the compound interest and is used by the banks.  The formula is so designed to calculate the interest n times the year and each time the interest is added to the principle enhancing it continuously.  This is called the compounding the interest . S = P*(1+r//n)^n*t    S--- Amount yielded.    P --- Principle    r--- Percentage rate of interest    n ---number of times interest compounded in a year.    t---- Number of years .       First, let us take the principle P as one dollar, rate of interest r as 100% = 100/100= 1; time t as one year and number of times n = 1, the interest is calculated only once at the end of the year.  So what is the yield S? S=1*(1+1/1)^1*1=1*(1+1)^1=2 So one dollar becomes 2 dollar at the end of a year for 100 % rate of interest.       Now let us compound the interest 3 times the year- i.e.- every four months.  So n = 3, retaining other quantities same, the

  Spherical shape :      When a clay like mass spins about itself(pot making), it is likely to attain spherical shape.  That is why all the celestial bodies are spherical.        All liquids have a property called surface tension.  That is, the liquids contract its surface area and try to occupy smallest area.  The sphere has a smallest surface area for a given volume.  Hence all liquid drops and water bubbles are spherical.        For the same reason, most fruits are spherical.  They try to contain good volume of food in efficient packages. Parabolic shape:      Parabolic mirrors efficiently reflects radiation as a parallel beam or focus the parallel beam of radiation to a point accurately.  Hence parabolic shape is used in antenna, telescope mirrors, car head light etc,.  Parabolic shape is also used in construction of buildings and bridges for its weight bearing character. Egg shape:      Egg has a peculiar shape.  But it has a purpose.  Roll down an egg on a table

    Moon is under the gravitational influence of the earth.  Hence it revolves around the earth. It completes one revolution around the earth in about 28 days(one month).  It also spins about itself in the same time . So naturally, it shows the same face to the earth always.  One can easily walk on the moon's surface and follow the sunset or sunrise since it spins slowly compared to the earth(24 hours).  Consequently the lunar day is nearly 28 earth days long.(14 days night; 14 days day)   While the earth orbits the sun, the earth carries the moon along with it.      The moon is the only astronomical object close to the earth.  Light takes 1.28 seconds to travel from moon to the earth.      Moon is the smaller body and hence it has small gravity. Your weight will be greatly reduced on the moon.      When a torch light is switched on the moon, one is not able to see the beam of light but only the patch of light on the surface.  It is because there is no dust particles to sca

      A motor mainly contains two components, a permanent magnet and a coil of wire.  We know that when a current is passed through the coil, a magnetic field is created. Action:      Alternating current is passed through the coil in the motor.  The direction of the current alternates frequently and hence the direction of the magnetic field created by the coil also changes.  The permanent magnet attracts or repels the coil according to the direction of the magnetic field.  Since the attraction and repulsion alternately happens, the coil begins to rotate .  This is the simplified explanation of the working of a motor.      Motor is main part in many house hold electric appliances.  For example:  hair drier, water pump, washing machine, fridge, AC, mixie, grinder, fan, vacuum cleaner and so on.      So a coil and the electromagnetic force plays the main role in  electrical engineering. Reverse action :     We understand, when alternating current is passed through the coil o

           How do  we see motion in a movie?  Let us find out      Whenever we see an object, its image falls on the screen (retina) of the eyes.  The image does not vanish immediately.  It stays in the retina for sometime(one tenth of a second. ). This is called persistence of the vision .  It may be a natural fault of the eye.  But it helps us to enjoy movie in theater and TV.        Look at the running fan.  The three blades cannot be seen clearly.  It is because the images  fall in the eyes; stays and overlaps.  Hence we see only fuzzy circle.      In a cinema, 16 pictures are projected on the screen in one second.  They fall in our eyes successively  and rapidly.  They create an illusion of continuous motion.  So we perceive movement in the cinema screen and TV from still pictures due to persistence of vision.       Todays animated GIF images in computers uses this principle. 

   J ust a pair of metal plates separated by a small distance is called "capacitor".  It can store electric field(charges) and release it.         A coil of wire can create magnetic field when electric current is passed through it.  Magnetic field depends on the strength of the current.  A coil of conductor is called an "inductor".        Let us connect a battery for some time to the capacitor till it fully charges up.  Next we will connect the capacitor and the inductor in parallel.  Now the actions starts.        The capacitors slowly discharges, current flows in the circuit and magnetic field builds up in the coil.      When the capacitor is fully discharged, the magnetic field of the coil starts to collapse and the current flows(Faraday's law)  in the same direction.  At the same time the capacitor is charged up in the opposite direction.      When the coil fully loses magnetic field, the capacitor starts to send the current in the opposite directio

   I have two numbers and I want to find the greatest common divisor (GCD) for them.  Then, I have to find all the factors of two numbers and select "the common big one" from both the set of factors.  It will be a tedious task for very big numbers.        There is a sleek procedure(algorithm) to do this .  This algorithm is devised by euclid in 300 B.C.   Let us find out GCD for 30 and 18 in euclid's way .        Divide the big integer by the small integer and get the remainder.         30 MOD 18 = 12 .    Now divide the divisor 18 by the remainder 12 and get the new remainder.         18 MOD 12 = 6 .    Next again, divide the divisor 12 by the remainder 6 and get the fresh remainder.         12 MOD 6 = 0      6 must be the GCD of 30 and 18  because it is derived from both the integers by repeated division and finally it divides perfectly without any remainder.  Verifying:      30 MOD 6 = 0      18 MOD 6 = 0      This is the good example for a computer

      White is a mixture of all colours or mixture of primary colours.  White surface reflects away all the light.        Black is the absence of light.  Black surface absorbs all the light.       Red, green and blue are said to be the primary colours.  All other millions of colours can be got by adding them properly.    Leaf looks green because it absorbs all the colours from sunlight except green which is reflected away by it.        When red object is viewed using green light, it will look black, because even that green light is absorbed by the red object and no light is emitted.     If an element (sodium, carbon) is burnt, it will emit certain colours of light(spectrum).  It is like signature of the element.  Element can be identified using that colours.       Only red laser and blue laser have been invented so for.  White laser is not possible, why?       There is no blue sky.  Sun's blue light is scattered by the atmosphere and we perceive i

    Water flows in the river and finally drains into the ocean without any use.  We build a dam across it.  Water is blocked by the dam and hence water pressure rises.  The high pressure water can be used to generate electricity.      Similarly, the current (electron) flows from positive to negative terminal of a battery when they are connected.  Now, insert a resistor in the path of current.   The resistor resists the flow of electrons and builds up electrical pressure (voltage , potential)across it.  It is according to ohms law V = IR. This electrical voltage can be extracted from resistor and can be used for any purpose.      So resistors are like dams that controls the flow of current and builds up required electrical potential.  There are no circuits without resistors.

     put a spoon in a glass which is half filled with water.  The spoon looks bent, because light traveling from air to water is bent(refracted).  why should light refract?      When light waves travel in a denser medium like water and glass, its slows down.  like we slow down, when we move into a knee deep water.       If all the light waves travels straight(perpendicular to the line of separation of two media) and enter the denser medium, the wave speed will decrease, but they will go undeviated.      But if the waves enter the line of separation at an angle (obliquely), part of the first wave front will enter the denser medium and" that part " will be slowed down; remaining part will move with original speed in the first medium.  This process causes the wavefront to bend.  similarly all the waves that follow will bend (when they enter) and follow a different path in the denser medium.      Without refraction of light,   lenses, prism, microscope, telescope and other

      We know there are four fundamental operations namely addition, subtraction, multiplication, and division.  Multiplication is the repeated addition and division is the repeated subtraction.  So we are left with only two fundamental operations addition and subtraction.  But subtraction can be done in terms of addition as follows.  To subtract 6 from 9 . get the 10's compliment of 6, which is 10-6 = 4 . add the 9 and the compliment     9+4 = 13 . then drop the carry 1 3 = 3 which is the answer.     So we require only addition .       In computers, all numbers are represented in binary. That is, in 0's and  1's .  So 1's compliment is 0 and 0's compliment is 1.  Hence computer does the subtraction in terms of addition easily.        Computer does all the mathematical operations using addition only.  It is easy for computers not for humans. 

      Suppose a boat crosses a flowing river from one bank to another straightly.  The boat will  appear to go and actually go in a inclined path.  This is due to net effect of river's velocity and boat's velocity.  To find boat's relative velocity with respect to the flowing river, we should use parallelogram law of vector addition .  That is, both the velocities should be added taking their directions into account.        Next, a man is running horizontally on the ground and the rain is falling vertically downwards (without wind).  To find the relative velocity of the rain with respect to the running man, we have to adopt the same method mentioned above.  Then we get that the rain will fall slantingly towards the man.  Here we add man's horizontal velocity and rain's vertical velocity vectorially.  Slanting rainfall can be observed in a moving car's window or in a moving train's window.        All velocities are measured relative to something.  No v