sciencecapsules

           How far and how clearly we can see? The star we see in the night sky is single or double?  The answer :  " We can at the most distinguish things that are 30 centimeters apart at a distance of 1 kilometer".  This result from the following formula   Angular dispersion of human eye A = 1.22*L/d  L - wave length of light  d - diameter of aperture of pupil of the eye.      We get A as 0.0003 radian. = 0.0003/1 = 0.0003 km/1 km  = 30 cm/1 km.        What is the angular dispersion? Why this restriction to human eye?  To explain that, we have to go to the physics principle-dispersion-diffraction.      Let us say, water flow from a lake through a narrow channel to another lake.  Once the water exists the channel it will spread out [Dispersion].  That is the nature of all  fluids.  But a stream of arrows or bullets passing t...

         Some where in the mountains, a river originates.  It flows down to the low-lands and into the sea.  It flows because of the slope and the gravity.  River appears to run on a plane ground.  But there is always a slight slope.      If one of the banks of a river is weak, the river burrows in and curves.  The curved flow of water hits the opposite bank and curves again. It repeats on and on.  That is why, all the rivers follow snake like path.      The river suddenly turns creating a whirlpool; it some times falls down creating waterfalls; it smashes on boulders and rocks; it splits up creating island; it finally enters ocean where again there is clash between land mass and waters.  Consequently river split up into several branches creating delta region.  Such a hard journey. The river's journey is similar to the human life.      The river is like conveyor...

        Look at the mirror.  If you do not like what you see, break it (take it lightly).  Again, in  each piece, your face appears.  Again break them all.  In all the pieces, your face appears and smile at you.  This is the way nature works.         Look at a tree.  Every branch is the replica of the tree.  And every sub-branch also.  You can see the pattern of tree in each leaf.  There is redundant information.  Nature uses redundancy to protect life forms.  DNA is present in each cell of life forms.  That is why, plants,can be grown not only from seeds but also from stems, roots and even leaves.      Hologram that is found in all the Id cards, credit cards etc. yields 3D picture.  "Optical interference pattern" is recorded in the hologram.  If you cut the hologram into pieces, one can get same 3D picture from each piece but smaller ...

          There are only 26 symbols in English.  Shakespeare has used only these symbols and written great dramas. To venture into math and accountancy, we need 10 more symbols (numbers).  For science and technology, we still needed more symbols.  And we borrowed them from Greek and Latin.  Also, we require punctuation for clarity.  That is human weakness, we need more and more symbols to understand a concept or a message.  But the nature has coded all the information using only four symbols (chemicals) in the DNA.  But only two symbols are enough to represent any info. in today's machines and digital devices. ACOUSTIC - MORSE CODE      In those days, Morse code were used for instant and emergency communications (Telegram).  Morse code consists of only 2 symbols dot and dash.  Dot means a sound signal of short duration.  Dash means a sound signal of lon...

          You cannot gain one thing without losing another.  No thorn, No rose.  That is the philosophy of life and as well as science.      Take a flowing air or water.  As the speed increases, the pressure should drop.  Or if the pressure rises, the speed will go down.  That is Bernoulli's principle employed in air-planes etc.      Consider falling stone, or water falls.  Here, as potential energy goes down, kinetic energy will pick up.      Next, Electric transformer, voltage can only be increased at the cost of current or vice versa.      Take gear systems, either force or speed can be increased.  Both cannot be increased together. whenever there is oxidation [lose of electrons, say,  at negative of battery], there must be reduction [gain of electrons at positive]       The principle of entropy, says that, if "o...

           Why the gas stove gives out blue flame?  Let us explore.       Origin of light:      When the charges (electrons, ions) vibrates, oscillating electric field is created.  Oscillating electric field subsequently gives rise to oscillating magnetic field.  Now the electromagnetic wave is born.  It will start to spread out. If the wave's frequency falls within the visible range, it is light.      Invisible Infra-red:      All the bodies in this world or in this universe have some temperature  above absolute zero kelvin.  Hence, atomic particles[charges] in these bodies execute vibrations due to heat.  They will start emitting electromagnetic waves[light waves]. If their temperature is less than 1000 k,  the frequency of waves will fall in infra-red range.  Humans, animals, trees, houses ...   always emit IR radiations.  He...

          We inhale oxygen and exhale carbon-di-oxide.  Plants take in carbon-di-oxide and give out oxygen during photosynthesis.  That is how, nature recycles the air.      Water flows through the rivers to the sea.  It is evaporated from the oceans to form clouds.  The clouds pour down as rain.  The fresh, pure water is not created out of nowhere.  Water is only recycled by the nature.  We buy, brand new, fresh water bottle.  It is neither new or fresh.  But, it is already used thousands and thousands of time.  It is smartly recycled by the nature and is given to us as fresh.      We eat the yields from the plants and trees.   Human and animal waste is the fertilizer for plants.  The entire Eco-system  goes on recycling.  Man is not able to create a closed Eco-system which recycles itself yet.      Even we are recycled....

              Stopping a car running at 60 kmph all of a sudden is equal to elephant falling from a third floor and hitting the ground.  Lot of energy has to be dissipated.  Engine is constructed in front portion of the car so that it can absorb the impact in case of the crash.  The front of the car should not be rigid.  It should absorb and dissipate the energy by crumbling and deforming .  The bumper is also used to absorb energy during the crash.  Besides, there are air bags in front of the passengers.      During an impact, there is a large deceleration (negative acceleration).  The loose and soft organs in the body cannot withstand such a force and energy.  Hence so many safety measures are built in a car.      Engine is at the front and the boot is at the back in every car to withstand the unexpected collision.  Wash rooms are kept at the two ends of ...

         We know reflection without which we cannot even see our own face.  Now let us explore the how and why of reflection.      The reflection obeys the law that "angle of incidence = angle of reflection ' (fig) why?  The light ray coming from the source hits on the mirror and bounce back.  For this process, the shortest and quickest path the ray can take leads to the law of reflection.        We see mirage in the hot summer on the roads.  It is also a kind of reflection.  Mirage appears because, the light ray takes quickest path to reach our eyes.      The brain always tells us about the position of the object using the path of light coming from it.  In a mirror reflection, the light rays seems to be coming from backside of the mirror.  Hence, we get the illusion that  the objects are situated behind the mirror.      A convex mirro...