SCIENCE CAPSULES

        "Camera".  Means a dark room.  Today camera watches us everywhere.  Nearly 2000 pictures are uploaded every second in face book.  How the camera came into being?  How people struggled to record an image?  Let us flip the pages of history.      Take a 'light tight' box and make pinhole at the center of one-face of the box.  Fix some transparent sheet opposite to the pin hole.  Light passes through the hole in straight lines and make a inverted image of the outside scenery.  That was first camera made.  Next lens came.  Even today, there is no replacement for lens.      Storing the image was great task then.  People tried Bitumen with some success.  Silver salts came to their rescue.  Silver salts are darkened by light.  This principle was used for a long time.  Next plastic film with silver halide coating.  The negative-positive technolo...

    "The humble screw thread may simply be an inclined plane wrapped around a cylinder, but without it, metaphorically and literally, the wheels would come off the modern world.  Nature barely uses the concept, but for mankind it holds false teeth in place, focuses microscopes, and fastens hatches onto spacecraft.  Screw threads also provide the precision movement that allows the automated manufacture of just about every piece of technology we take for granted.  Without the screw thread our world would be a very different place" -Jem stansfield.      The 'screw threads' is so called because the ridge spiraling down the body of the screw is known as the thread. the functions of 'thread'; 1. Converts rotational motion into linear motion. 2. It fastens two things. 3. It amplifies motion as in micrometer.     The tightening of a fastener's screw thread is comparable to driving a wedge into a gap until it sticks fast through...

         What is exactly average or mean?      Consider the numbers, 14,15, 16, 12.  Add them and divide by 4.  We get 14 14+15+16+12 = 56 also 14+14+14+14 =56      Hence 14 is the representative of the group of four numbers or 14 represents each number.  That is what we call mean.  This is especially called Arithmatic Mean.(AM)  We think that only 'this average exists, but ther are variety of means we have to choose proper mean for each situation. GEOMETRIC MEAN      Suppose your salary doubles every 5 years.  20k,40k,80k, 160k.  What is average increase for every five years.  Here, these numbers have multiplicative relationship not additive relationship.  Hence multiply all the numbers and take fourth root of the answer .  Since there are 4 numbers.     Fourth root of (20*40*80*160) is 56.56k 20*40*80*160 =10240000.  Also the geometric me...

WHEN THE TIME STOPS?      To  measure time, something has to tick, for example: pendulum, quartz crystal vibrations, watch movement, atomic vibrations etc.  For something to tick, energy is required.  If we reduce the energy to nothing, that is if we reduce the temperature to absolute zero, we remove all the heat energy, everything will freeze and the time come to a stand still.  It is said before the 'big bang' that is, before the birth of universe, time did not exist. SPEED OF THOUGHT      Human neurons fire up to 500 times per second, releasing a new impulse every 2 milliseconds.  That is we may get an 'idea' every 2 milliseconds.  But a supercomputer does 200 peta flops -200 quadrillion operations per second.  To  match that, a human brain has to make one calculation per second for the next 6.3 billion years. OUR EYE'S PERCEPTION      We can process and interpret images we see  in a...

         Harry is working in a restaurant.  He has to make a pot of soup every night for the next day.  His problem:  How long to wait for the boiling soup to cool down to room temperature?  Because he has to put the soup in the fridge before closing the shop.  He can speed up the cooling process by placing the closed soup pot under flowing cool tap water.      He knows one fact; it takes 10 minutes to cool down to  60 degree from 100 degree.  If he knows "rate of cooling", he can easily calculate the time the soup will take to reach room temperature.  Here, an important and universal formula  comes to our help.       T = T0*eˆ(-Rt} T - Temperature at the moment = 60 degree T0 - Initial temperature = 100 degree e - Euler's constant = 2.71... R - Rate of cooling - to find t - elapsed time -10 minutes. By pluging in all the values, we get rate of cooling R  as 0.051 degr...

         All hotels in dubai are good and have standard facilities.  We are picked up from Airport by hotel van.  After checking in, we were given a key-card.  Even entering a elevator requires that card.  At the wave of the card, the room opened.  It had central airconditioning system.  The temperature of the room can be controlled using a small electronic digital device embedded in the wall.  The room had large french window overlooking the  broad roads.  The room had, small fridge built in under the desk, a small safe, coffee maker and required supplies, ward robe, iron box,  ironing table, prayer mat, quran book, twin bed and a well designed sofa-cum-bed  plus usual things like phone, TV etc.  The bed cover is soft and double walled.  No fans and air-cooler any where in Dubai.      The rest room deserves a special mention.  It had cold and hot water taps running 24*7....

  HALF LIFE:  We have studied 'Radioactivity' in our school days.  Some unstable atoms emit radiations and become the atoms of another stable element.  For example, 'Uranium' is radioactive and step by step becomes 'lead'.     This we call 'exponential decay'.  When the overhead tank' is full, water will come out through the tap forcibly with high presssure.  As the water level decreases in the tank, the presssure goes down and finally water drips through the pipe.  In a 'exponential decay', the process will take infinite time to complete.  Hence, to get the idea of the 'age' or life time of radioactivve element, we measure half life'. In the case of 'Radioactivity' the 'element of chance' is also present.     What is half life?  In the case of radioactivity, the time taken for the half of the original atoms to become atoms of another lelment.  'OR'.  The time taken for the 'effects of anything...