SCIENCE-KNOWLEDGE

Science: What's & Why's Engineering &Technology, Physics, General Science, Chemistry , Animal & Plants Science, Geography, Human Science, Modern & Nuclear Physics, Space Science.

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Tuesday, December 24, 2019

How Videos Work ? How do we watch Movies ?

Abhijeet December 24, 2019
How Videos Work ? How do we watch Movies ?

                               Ans: A video is nothing but a collection of images which are displayed to our eyes continuously with a very short time interval between them. let us see what do we mean by it.

                  when we look at any object, its image is made on rating of human eyes. These images do not get removed from the retina even after removing the object from in front of the eyes.
                 
                  Due to the same attributes of the eye. the video is produced. Continuous photos are flashed so fast that the effect of the picture is not completely eradicated and this happens so fast that it becomes difficult for us to understand these pictures separately and their mixed effect gives us an impression of being dynamic (Video).              

Monday, December 23, 2019

What is X-Ray ?

Abhijeet December 23, 2019
What is X-Ray ?


                          X-Rays are a from of electromagnetic radiation, as a is visible light, but with some different characteristics.
            The important characteristic of X-Rays is that these can penetrate or pass through the human body but cannot pass through bones, hard items like bullets etc. This effect produces shadow-like images of structures such as bones, bullets etc. on a photographic plate. This helps to understand the inner details of body such as presence of foreign hard  (bullets etc.) or any fracture in the bones.



Wednesday, February 6, 2019

How does Thermometer Works?

Abhijeet February 06, 2019
How does Thermometer Works? 
Answer : 
            Thermometer works on the principle of Thermal Expansion. All metals expand with increase in temperature &vice versa i.e. decrease in size with decrease in temperature. 
           In a common thermometer as shown in figure above, in the bottom small bulb, Mercury ( a metal ) is kept. It is worth mentioning hat mercury is unique in the sense that 
i. it is the only metal which is a liquid at room temperature & 
ii. it coefficient of thermal expansion is pretty high i.e it the change in volume ( or length of a fix area liquid column is very large).
                This mercury rise up and down in the thermometer tube with increase & decrease in temperature . The tube is marked with temperature readings and can be read directly.

 How do we define 1*C temperature- 
                       its simple As a convention it is assumed that the pure water boils at 100*C & gets converted into ice at 0*C.
                       The thermometer is kept in a boiling water. This gives us the mark of 100* C. Again, the thermometer is kept in an ice-water mixture. This gives us the 0*C mark.
                       The intermediate length between these 2 marks is divided into 100 parts. Each partitions corresponds to 1*C temp rise or decrease.

Sunday, January 27, 2019

How Coal and Petroleum is formed?

Abhijeet January 27, 2019
How Coal and Petroleum is formed?
 Answer : 
               Coal and petroleum have been formed from remains of dead animals and plants which has been subjected to various biological and geological process over millions of years.
Coal is the remains of trees, ferns and other plants that lived millions of years ago while oil is the remains of millions of tiny plants and animals that lived earthquakes or volcanic eruptions. They were pressed down under the layer of earth and rock and slowly decayed into the coal under the high temperature and pressure. 

Thursday, January 24, 2019

What's the difference between LCD and LED TV?

Abhijeet January 24, 2019
What's the difference between LCD and LED TV? 
  Answer : 
              The only difference between the two is how the light is generated at the back of the screen. Let us see what this exactly means.
How an LCD Television Works 
LCD television Screens are made up of a liquid-crystal gel sandwiched between two panes of polarized glass When yo power on the television, the electric current passes through the liquid-crystal display, altering  its structure. The liquid-crystal molecules coil and uncoil. The creates a shuttering effect, whereby light is either allowed to pass through or not. This variation in light and dark on the screen, is what the viewer perceives as images.
Unlike plasma TVs, the liquid- crystal does not create its own light. It requires another light light source. In the case of LCD TVs, the screen is lit by fluorescent tubes.
How an LED Television Works 
An LED TV is just a new generation of LCD TV. The difference is that an LED TV is not lit using fluorescent tubes,but rather a series of light emitting diodes (LEDs).There are tree basic types of LED televisions, ans each has its own specific format.

Tuesday, January 22, 2019

Computer : How does it work?

Abhijeet January 22, 2019
Computer : How does it work?
  Answer : 
             A computer is an electronic machine that processes information , it takes in raw information (or data), stores it unit its ready to work on it, chews and crunches it for a bit, then spits out the results at the other end. All these processes have a name. Taking in information is called input , storing information is batter known as memory (or storage), chewing information is also known as processing, and spitting out results is called output.

 Input: Your keyboard and mouse, for example, are just input units-ways of getting information into your computer that it can process.
Memory/Storage : Your computer storage all documents and files on a hard-drive: a huge magnetic memory.
Processing : Your computer's processor (sometimes known as the Central Processing Unit) is a microchip buried deep inside. it
Output : Desktop (monitor), printer etc.are the output tools through which we get the information out.
An O.S & a computer Program (software)-
  A computer program or software is line of code that tells computer how to identify the data, process it and get the final output in the form of a mathematical solution of GUI display. 
There is something called Operating System (O.S) e.g. Linux, Windows 10 which does this task. All other software interact with O.S. only to carry out different functionalities.

Do you know : Why electric wires are made up of copper ?

Abhijeet January 22, 2019
Do you know : Why electric wires are made up of copper ? 
 Answer : 
            Copper is good conductor of electricity which is the time requirement. At the same time it is also highly ductile . can be easily drawn into wires. copper is readily available and is also cheap. That is why electric wires are made up or copper.

Monday, January 21, 2019

Oil fire cannot be extinguish with water. Why?

Abhijeet January 21, 2019
Oil fire cannot be extinguish with water. Why?
 Answer : 
          Since the specific gravity of oil is less than water, it vats over water. As a result, water will not put out oil fires once the burning oil will float on top of the water and read.

            Rowing sand, table salt, or banking soda on the flames will distinguish them. Also a damp towel spread over the fire will col nd smother it but all the water must be wrung out. 

When do things catch fire ? What is fire actually ?

Abhijeet January 21, 2019
When do things catch fire ? What is fire actually ? 
 Answer : 
              There is something called ignition Temperature. monition 
temperature is the minimum temperature at which things catch fire and also they can maintain a continuous time.
              when the temperature of a body reaches this temperature, even it starts burning. The ignition temperature of common catch sticks is 600-800 degree C.
 Sow what is fire?  
              Fire actually nothing but reaction of any material with oxygen. In this reaction, Carbon present in the material gets converted into CO2 and energy is released .
released energy is the cause of heat.
C+O2aCO2+energy(Heat)

Sunday, January 20, 2019

Bicycle frames are made of hollow pipes. why?

Abhijeet January 20, 2019
Bicycle frames are made of hollow pipes. why? 
 Answer : 
               A tube is more efficient than a solid in terms of length to weight ratio. So, bicycles frames are made of hollow pipe to get the maximum strength while keeping the weight to a minimum
.
               However, if you ignore the weight benefit of a tube, the solid feel is stronger of the same diameter.

How does fog light work in a car ?

Abhijeet January 20, 2019
How does fog light work in a car ?
  Answer : 
             Front fog lights are of use in extremely poor visibility. In this situation, the normal low-beam lights reflect off the in front.
           front fog lights are mounted low down on the bodywork, and angled down at a steeper angle than normal headlights. The beam pattern is wide and flat, with a distinct cutoff at the top-this reduces the amount of light reflecting off the fog. By switching the low-beam lights off, the driver can use the fog lights to illuminate the load directly in front of them, so they can proceed at low speed.

What is dry Ice ?

Abhijeet January 20, 2019
What is dry  Ice ? 
 Answer : 
            Dry ice is the solid from of carbon dioxide. It is used primarily as a cooling agent or fire extinguisher. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental from moisture in the atmosphere). It is useful for preserving frozen foods where mechanical  cooling is unavailable.
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Saturday, January 19, 2019

iron rusting-what causes iron to rust ?

Abhijeet January 19, 2019
iron rusting-what causes  iron to rust ?
  Answer : 
             Rust is actually oxide of iron. Rusting is nothing but the reactions of iron with oxygen.
             When iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time.Over time ,the oxygen combines with the metal at an atomic level, forming a new compound (oxide).
            The compound formed by this reaction, the rust is a weaker material and it makes the structure brittle.
          Rust was originally a synonym for iron oxides, but is now the general term for metal corrosion. It is a flaky and fragile substance, which is undesirable for most metal rusts depends on its surface area and environment. Moist environments cause significant rust, while salt water accelerates rusting even further .
            

Why the dust sticks onto ceiling fan blades ?

Abhijeet January 19, 2019
Why the dust sticks onto ceiling fan blades ?   
  Answer: 
               As the fan blades cut through air, they develop charge due to friction. This leads to accumulation of dust particles as these dust particles as also usually charged.

           The leading edges of the blades usually develops the thickest layer of dust. That's because the leading edge [the edge first cutting the air as the blade spins] encounters the most friction and develops the largest charge.

How does microscope works ?

Abhijeet January 19, 2019
How does microscope works ?
Answer :
           Microscopy is a branch of science, in which microscope a neutral organisms are able to see which cannot be seen with simple with eyes.
         The single convex lens can be called the the simplest microscope. It can magnify the image of an object is the object is kept a appropriate (within ifs focal length ).
        Simple microscope cons
ist of a combination of two or more numbers of convex lenses at a appropriate distances. These distances are set such that the image formed by the first lens gets further magnified by the 2nd & 3rd lenses. Hence, the much higher magnifications.
              

How paper is made ?

Abhijeet January 19, 2019
How paper is made ? 
Answer : 
          Have you ever wondered where does the paper comes from! How it is manufactured!
         Paper which over which students write their notes, newspapers are printed even our currency notes are made of paper.


         paper is made from woods and wooden mixtures (buraada).

         process of paper-making- The wood from the tress is made into fibrous from (buraada). This fiber is mixed with water & other chemicals and through a pressers and convert thin sheets . then, this water is dried up leaving behind thin sheets of paper.
       How important the trees are for human life is very well known to all of us. Therefore, one should never waste the paper .

         

How does a fire extinguisher work ?

Abhijeet January 19, 2019
How does a fire extinguisher work ?
 Answer : 
              All of you might have seen fire extinguisher cylinders. How it works and how it is operated, we will discuss here.
              At the top of the cylinder, there is a small cylindrical container filled with compressed gas. The release valve acts as a locking mechanism and prevents this gas from avoiding. When you pull the liver, the pushes a stick which opens the path of the nozzle to suppress the valve. Compressed gas has been released, low pressure is used on fire extinguishing material, and exits the nozzle under tremendous strength.
           CO2 firefighters are commonly used. carbon dioxide is non- flammable gas. As we know that CO2 is heavier than oxygen and is very cold, it removes oxygen from the surrounding area or cools the fuel.
              How to operate these- See the figure below for this . The keyword here is PASS. Each letter of this word is explained in the figure.

e-cigaratte : What is it ?

Abhijeet January 19, 2019
e-cigarette : What is it ?

 Answer : 
              In the days on internet, everything is going the e-way. e-rail, e-ticketing, e-shopping, e-cigarette. Many of you might have heard about it. Let us see what it is, how it works and if it is hazardous for human.
             E-cigarettes also known as electronic cigarette or vaporizer cigarettes are devices that emit doses of vaporizer nicotine which is inhaled. The device is battery-operated and can also emit non-nicotine vaporized solutions. Manufactures say they are an alternative for tobacco smokers who want avoid inhaling smoke.
               E-cigarettes are long-shaped tubes, many look like the product the user used to smoke, such as a cigarette, cigar or pipe. some look like ballpoint pens. The majority are reusable with replaceable and refillable cartridges. A small percentage of products are throw-away ones- disposable e-cigarettes. 

---Cigarette e or non-e are injurious to human health and must be avoided.

Friday, January 18, 2019

Artificial Intelligence - What is it ?

Abhijeet January 18, 2019
Artificial Intelligence - What is it ?
  Answer : 
                Many of you might have seen the famous Hollywood movie series Terminator. May be some of you might not have seen the movie terminator but all of you would have seen superstar Rajnikanth's movie Robot and Robot 2.0. In these films robots are shown as intelligent beings. they have brains and take independent decisions. But how exactly these robots do that. Answer is Artificial Intelligence. What it is and how it works,we will discuss.
              Before coming to Artificially Intelligence (AI), one needs to know what intelligence is.
What is Intelligence ?
               By definition, it is the ability to calculate,reason, perceive relationship and analogies, learn from experience, store and retrieve information from memory,solve problems, comprehend complex ideas, use natural language fluently, classify, generalize, and adapt new situations.  
             In general terms, its all those thins that human brain does.
Artificial Intelligence (A.I) is a way of making a computer, a computer-controlled robot, or a software think intelligently,in the manner the intelligent humans think,
           Al is accomplished by studying how human brain thinks, and how humans learn , decide, and work while trying to solve a problem, and the outcomes of this study as a  developing intelligent software and systems. 
            It is not more programming a robot we are talking about. Al basically goes mach beyond that. it works on fuzzy logics, data mapping and screening and making decisions.

How does brakes of a car work ?

Abhijeet January 18, 2019
How does brakes of  a car work ?  
 Answer : 
           We all know that pushing down on the brake pedal slows a car to a stop. But how does this happen? How does your leg to its wheels? How does it multiply the force so that it is enough to stop something as big as a car ?
            When you depress your brake pedal, your car transmits the force from your foot to its brakes through a fluid. Since the actual brake require a much greater force than you could apply with your leg, your car must also multiply the force of your foot. it does this in two ways:

       1. Mechanical Advantage (leverage)
      2.  Hydraulic force multiplication 

 The brake transmit the force to the tires using friction, and the tires transmit that force to the road using friction also.
               

Thursday, January 17, 2019

How does the car's airbag work ?

Abhijeet January 17, 2019
How does the car's airbag work ?
  Answer : 
             An airbag is something which helps safety of driver & passengers in the event of an accident . In the event of an accident, the airbags open automatically within fraction of a second and cover the body of personnel inside.
 How does an Airbag works-
                  An airbag is more correctly known as a Supplementary* Restraint System (SRS) or Supplementary Inflatable Restraint (SIR).
           There are three parts to an air bag. First, there is the bag itself, which is made of thin, nylon fabric and folded into the steering wheel or the dash board. Then there if the sensor that tells the bag to inflate. It detects a collision and auto-activates system.
           Finally, there is the inflation system. Air bags are actually inflated by the equivalent of a solid rocket booster. Sodium Azide (NaN3) and potassium nitrate (KNO3) react very quickly to produce a large pulse of hot nitrogen gas. This gas inflates the bag is already deflating (it has holes in it ) in order to get out of your way.

*The word "supplementary" here means that the airbag is designed to help the seat belts protect you rather than replace them(relying on an airbag to protect you without fastening your seat belt is extremely dangerous ).

How does motor car works ?

Abhijeet January 17, 2019
How does motor car works ?
 Answer : 
               Modern day life cannot be imagined without cars, trains, motor-cycles etc. All of us know that there engines run on diesel or petrol as fuel but, how exactly diesel or petrol makes these machines run ? What's the science behind it? these are a few questions we will try to address through question. So,get along....
How does a car engine works-
           The car or vehicle runs by energy released in the engine by burning fuel. The chemical energy of fuel is converted into heat energy which moves the piston. There are 4 stages or strokes as we call it in this energy conversion cycle. these are shown in the figure below.
 4 Stage/Strokes Engine : Working Mechanism-
           There is a cylinder which houses a piston, intake valve, exhaust valve, fuel injection system. the piston in turn is connected to a crank-shaft. 
Intake stroke- The piston in the cylinder in the cylinder is going down. Intake valve is Open. The air enters through this valve which fills the cylinder.
Compression Stroke- The piston moves upwards pushing the air inside. The Intake valve remains closed. Hence, the air in the cylinder gets compressed and heated up.
Power Stroke : When the piston reaches at the top end,the air inside is at very high temp. (greater than 1000 degree C ). At this  instant, the fuel (diesel) is injected into the cylinder. The moment is enters in to the cylinder, it catches fire & huge volume of gases is produced and pressure rises to very high level. Hence the piston is pushed back downwards and crank rotates.
Exhaust Stroke- This is the 4th and final stroke in this cycle. At the end of power stroke,when the piston is at the cylinder bottom,the exhaust this valve. As the crankshaft is rotating,the
piston starts upwards movement and helps flush the gases out.
              At the end of this exhaust stroke, the intake valve again opens is converted into repeats. the linear motion of the shaft which rotates the wheels and thus car runs.

How does a scanner work ?

Abhijeet January 17, 2019
How does a scanner work ?
 Answer : 
              A Scanner is a device that analyzes the surface of an image, printed text or an object and converts it into a two-dimensional digital image.
               Scanners come in different shapes and sizes depending on the intended use. The most common scanner for home and offices today is the flatbed scanner .
              this type of scanner is sometimes called reflective scanner because it works by shining white light onto the object to be scanned and reading the intensity and color of light that is reflected from it, usually a line at a time. There are two types of flatbed scanners, CCD scanner, CIS scanner.

Jugaad ! What do we mean by it ?

Abhijeet January 17, 2019
Jugaad ! What do we mean by it ?
 Answer : 

              Jugaad (From Hindi), used in India,quite often in general means finding a low-cost solution to any problem in an intelligent way.
             It usually is a new way to think constructively and different about a problem. it has come to symbolize innovative out-of-the-box engineering which uses limited resources to fashion cheap solutions to real problems. 

               This word has now widened in ambit and now is very close the English word,"hack"
         

1G,2G,3G,4G What's the difference ?

Abhijeet January 17, 2019
1G,2G,3G,4G What's the difference ?
 Answer : All of us these terms on daily basis. we had GPRS earlier. Then came 3g, then 4g and now people are talking about 5g. What exactly these are & what do they specify see.
         The 'G' here, refers to the "generation" of wireless network technology. 

 1G networks (NMT, C-Nets, AMPS, TACS) are considered to be the first analog cellular systems launched early 1990s. there were radio telephone systems . 1G networks were conceived and designed   purely your voice calls with almost no consideration or of data services. 
2G networks (GSm, CDMAOne, D-AMPS) are the first digital cellular systems launched early 1990s, offering improved sound quality, better security and higher total capacity. GSM supports circuit-switched data (CSD), allowing users to place dial-up data calls digitally , so that the network's switching station receives actual ones and zeroes rather than the screech of an analog modem.
2.5G networks (GPRS,CDMA2000 1x) are the enhanced versions of 2G networks with theoretical data rates up to about 144 kbit/s. GPRS offered the first always-on data service.
3G networks (UMTS FDD and TDD,CDMA2000 1x EVDO, EDGE) are newer cellular networks that have data rates of 384 kbit/s and more.
4G technology refers to the fourth generation of mobile phone communication standards. LTE and WiMAX are marketed as parts of this generation, even though they fall short of the actual standard.

Wednesday, January 16, 2019

How does a website work ? What is web hosting ?

Abhijeet January 16, 2019
How does a website work ? What is web hosting ?
 Ans : 
           Like  mentioned earlier too, this is the age of Internet. Shopping , ticket booking, studies, games, services, all these are happening from the comfort your house by this miracle of modern science, Internet. But how many of you know how exactly a website work ?
            Let us take our own website www.scigyan.in. www.scigyan.in is the name of website &if is called a Domain in internet terms.Website actually is a collection of document and files made up of text,graphics,colors,links etc. stored on our web hosting servers (hosting server on this we will talk soon). so, the domain name acts as identifier for any website.
       A web hosting server (e.g. www.GoDaddy.com) is an Internet hosting service provider. It is where all the files of any domain name are stored. It allows individuals and organizations to make their website accessible via the World Wide Web.
              When you type a domain name viz. www.scigyan.in in your web browser such as google chrome, Mozilla Firefox etc. your browser sends a request for hosting web server where the files of the website are located. When connecting gets establishes, your browser downloads these files from that server in the from of html files or document, as well as images or videos, and renders them om to your computer screen. 
          Web hosts are companies that provider space on a servers owned or leased for   use by clients, as well as providing internet connectivity, typically in a data center. 
            To operate a website, only a domain name is not sufficient. One must have hosting services provider or host himself which usually is way too costly for common man. Big companies such as Google, Facebook etc. have their own servers.
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Tuesday, January 15, 2019

Who invented the internet ? How does the internet works ?

Abhijeet January 15, 2019
Who invented the internet ? How does the internet works ?
Ans : 
          This is the age of the Internet.
Internet has practically revolutionized
each and every facade of human life.
But, how exactly internet works!
let us try to understand the science behind
it.
        To start with Vinton Cerf and Robert Kahn are credited with the invention of the Internet.

 How Internet works-
                Each computer connected to the internet is part of a global network in which every computer has a unique address. Internet addresses are in the from of nnn.nnn.nnn.nnn, where nnn is a number from 0 - 255.  this address is an IP (Internet Protocol ) address is known as (IP address).
         Two computers connected to the internet. Your computer with IP address 1.2.3.4 and IP address 5.6.7.8.
            When you connect to the internet through an internet service provider (ISP),computers are connected to each other using this IP address.
              When you type a domain name viz www.google.in 
in your web browser such as google chrome, your browser sends a request for hosting web server where the files of the website are located. When connection gets established, your browser download these files from that server in the form of html files or document, as well as images or video, and renders them on to your computer screen. 
          This is how internet works. www in the domain names stands for world wide web. it acts as identifier for the web browsers.

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