SCIENCE CAPSULES

                Is  it ? yes.      Let us say,  long long ago Socrates  took a cupful of water from sea-shore and washed his face.  Today, you took a cupful of water from the sea near your place and washed  your face.  Have you used any of the water molecules that Socrates used long back?  You may think the chances are highly remote.  But the scientific answer is really surprising. A little calculation: you may skip      The total mass of earth's  oceans = 10ˆ18 metric ton.          or    10ˆ24 grams.      Mass of one water molecule= 3*10ˆ-23 gm. Hence No. of molecules in the ocean = 3* 10ˆ46 Mass of water in a cup = 250 gm. No. of water molecules in a cup =8.3*10ˆ24 No. of cups of water in the oceans = No. of molecules in the oceans/ No. of molecules in a cup             ...

        When x-rays passed into the body, it casts shadow of the bones.  A doctor can read x-ray film and diagnose.  But the body is also made up of soft tissues, nerves, muscles, fluids.  They cannot be detected using x-rays.  The 'magnetic resonance imaging (MRI) gives the full picture.      Our body mostly contains water, we know each water molecule has one oxygen atom and two hydrogen atoms.  Hydrogen atom is nothing but a single proton.  So each water molecule has two single protons. Proton is positively charged and spins like earth and moon.  When a charge spins, it acts like piece of magnet.  Hence each water molecule is a magnet.  (or 2 magnets) .  These magnets are oriented in various directions normally.      A patient is put inside the MRI machine and a strong magnetic field is applied to the body.  This field is a thousand times powerful than that of a fridge mag...

      Plastic is a wonder material  It is versatile, highly useful and is everywhere.  We cannot think of modern life without plastic.      It is easy to dismiss plastic as cheap and nasty material that wreck the planet.  But if you look around, the reality is different.  If you want cars, toys, replacement body parts, medical adhesives, paints, computers, water pipes, fiber-optic cables, and a million other things,  You will need plastics as well.  You cannot wish away the plastic.  We have to smartly live with it.      What is plastic?  Consider one ethane molecule.  It is just made up of 2 carbon atoms and 4 hydrogen atoms.  We can call it as a 'Monomer'.  Suppose, we  join number of ethane molecules as a chain, we get a big molecule of 'polythene'.  It is a polymer and the process is polymerization.  If  a number of chained molecules are combined togeth...

     Take a piece of rubber.  Stretch it.  It will elongate lengthwise but will contract breadth wise.  Now compress it.  It gets shortened length wise.  But stretches breadth-wise.  Rubber is said to have 'positive poisson's ratio'. \      Suppose, we use rubber cork with wine bottle.  When we press it into the mouth of the bottle, it will expand sideways.  It may not go inside.  It may even break the neck of the bottle.  The wooden cork has 'zero poison's ratio'.  That means, forces causes no effect in it.  Hence, we can easily close and open the bottle with it.      There are some materials with negative poison's ratio.  They are called "auxetic material".  They have special structures as shown in the figure.  Hence, their behavior is exactly opposite to that of the rubber.  When stretched, they elongate on both sides.  When compressed,...

         Draw a straight line. Remove the middle one-third and draw the two segments of line again. In each segment, remove the middle one-third portion again, and draw the four pieces of the line below it. Just go on repeating the process. We finally get the dust of points.      The first line is having the dimension one. The next segments of lines have a dimension less than 1 because they do not occupy the entire line fully. This pattern has only fractional dimension and hence it is called 'fractal'.       Imagine, the length of the first line is marked as in the scale from 0 to 1 in fractions. When the middle portion is cut off, the ends of two segments must have the marking 0 - 1/3 and 2/3 -1. When the two segments are redrawn by applying the same rule, the marking at the ends of the four segments is 0 -1/9, 2/9-1/3, 2/3 - 7/9 and 8/9 - 1. The process can be repeated without end. We get a set of numbers called 'c...

         We have a football field, a field of valleys and hills.  What exactly a field is ?  It can be thought as a area containing many, many points.  Each point may have a value like its height, its  temperature, its greenness etc.      Consider an LED lamp.  There is field of light around it.  But, this is 3-dimensional field unlike surface area.  The light is very bright close to the bulb and the light fads away with the distance.  This kind of fields always follow 'inverse square law'.  It says that the decrease in intensity (of light) is proportional to the square of the distance.  Our eyes can sense the light.  If you put any light sensitive-device in this field, it will be activated, example - light powered calculator.     Now consider a magnet, there is a magnetic field around it similar to the light field.  But it is not visible.  Only another magnet...

      Let us recollect the binary system of numbers.             binary      0 - 0      1 - 1      2 - 10      3 - 11      4 - 100   and so on.      Hence all numbers can be represented in 1 s and 0 s.      Let us now come to four fundamental operations.      4 * 2= 8, that is adding 2, 4 times gives 8.  Hence multiplication is the repeated addition.      8/2 = 4, you can subtract 2, four times in 8.  Hence division is the repeated subtraction.      Now, we are left with only two operations '+' and '-" .      Even subtraction can be done through addition.  Let us see now.  To subtract 6  from 8, take the 10's compliment of 6.  Subtract 6 from 10 and get 4 which is 10's compliment .  Now add 8 and 4 to get 12.  D...