sciencecapsules

        "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...

           Today, multistorey buildings are common.  To build a sky scrapper, we have to lift concrete, steel and other materials to a certain height.  So, first they build a tower crane.  One can see this crane near any tall building under constuction.  First, let us understand the principle of this crane.      Take a meter scale and hang it at the 50th cm.  Take a 150 gm weight and hang it 10 cm (at 40 cm) from the centre of the scale (50cm).  Now the moment of this weight is 'weight * distance' from centre.      Moment of 150 gm = 150*10 = 1500 gm cm.  If you hang only this weight, the scale will tilt to one side and collapse.      Take another weight of 50 gm and hang it 30 cm from the centre on the other side (at 80cm). Moment of 50 gm  weight = 50 * 30 = 1500 gm centimeter.      The two moments of these two weights are equal.  Hence th...

ROADS:      Dubai has one of the world's perfect transport system.  There are some 6 + 6 lanes roads with  two walking platforms and service road inbetween.  On the pavements plants are grown with tube irrigation system.  The roads are really clean.  One cannot cross that broad roads.  One has to use bridges.  The bridge can be accessed using public elevators.  The entire road space is cement covered.  Hence, even though it is a city of sand (dessert),  One cannot see sand dust anywhere.  The bus shelters are airconditioned. BUSES:      One has to purchase 'travelling card' and load it with money (Dhirams).  Charging the card can be done at any bus stop.  In the machine, just insert dhiram-Notes, enter the amount; touch the card (RFID technology).  The money will be loaded.      The buses arrive and stand properly adjacent to the platform.  (Roads,and bus sto...

            We know the importance of google map today.  How to make a map?  Earth is spherical, how to flatten it?  When we look at a piece of land, it looks flat.  Because the area is small.  Hence making a map of a small town is easy.  When we stand at the sea-shore and look at the ocean, we see horizon where the sky seems to meet the ocean.  Horizon appears because of earth's curvature.      A map is should be fairly accurate.  It should help long distance traveller (ship, airplanes).  It should also meet eduction needs.  We are going to use projection method for making a map.      Imagine a 'earth globe' made out of glass.  And a transparent real map is drawn on it.  We also put a powerful LED  lamp at the centre of the glass globe.  Put a cylindrical lampshade made out of white p[aper around it.  The lampshade should be just touching the si...

          On earth, gravity determines up and down.  Gravity pulls everything down.  Light objects carried up by the wind.  NASA Astronauts used to have a hanging doll in their cockpit. Once they leave the earth's gravitational field, the hanging doll starts to lift up and float.  The sense of 'up and down' goes off.  Every loose object starts to fly and float.      On earth, sleeping means lying down on a bed.  In space station at zero gravity, one can sleep at any position.  He has to strap himself with the wall, else he will float and wake up at the other end of the space station.  Pouring water works easily on earth due to gravity.  But pouring down is impossible in the space.  In the vast empty cosmic space, directions, back and front, up and down - all goes meaning less.      Consider a fly, flying inside a room, in curvy-turvy, zig-zag path. For the fly, above the ...

            Your smart phone mainly made up of pure sand-silicon.  Yes, It is true.  Mostly life forms are carbon based.  But the electronic gadgets are silicon based (Today).  Life forms are made of cells.  But electronic goods are made of 'transistors'.      What is transistor?  It has three parts Emitter, base and collector.  We can give input signal (voltage) to any pair (eg: base and emitter) and get output voltage from another pair(emitter and collector).  One can control output voltages using tiny input signals.  Hence amplification  is possible in it.  Transistor can be used as a switch (ON and OFF ) .  Hence Binary numbers (0 and 1 ) can be stored and manipulated by transistors.  Transistors are found in thousands or even in millions in many  electronic devices.  Computers, internet, smartphone, Automobile electronics, Medical electronics, all made pos...