Friday, October 24, 2014


We all must be familiar with microwave ovens now-a-days due to its advantage of fast and better cooking. In America, 90% of the homes use microwave oven for cooking. In India yet the percentage is some less but it is becoming very popular that more and more people are adapting microwave cooking.

Let’s have a picture of the story how it was invented. It is very interesting to know that microwave oven was invented accidentally in a lab. Actually there was no research going on to find better and faster way of cooking.

During a Radar related research project around 1946, Dr. Percy Spencer was working as an engineer with Raytheon Corporation. A new vacuum tube called Magnetron (a tube that produces microwaves) was being tested in the lab. Dr. Spencer discovered something unusual one day. He found that a candy bar kept in his pocket had melted.

This amazed Spencer very much. He then tried another experiments. He pointed the magnetron tube on a bag of popcorn kernels and stand at a distance away. He observed the popcorn cracked and popped all over his lab.

Next day, he tried again with an egg. What he found…the egg was exploded in few seconds. All these three experiments compelled him to come to a conclusion that in each case due to the exposure to low density microwave energy, food can be cooked faster just like candy bar, popcorn and egg.

Experimentation started with other engineers at Raytheon on Spencer’s new idea to refine it for practical use.

Spencer fed a metal box with microwave power using an opening and made arrangement that this energy was unable to escape. When food was placed in the box, temperature of food rose rapidly.

By late 1946, the Raytheon Company had filed a patent proposing that microwave energy can be used to cook food.

In 1947, Spencer demonstrated the world's first microwave oven and called it a "Radarange".

The oven that heated food using microwave energy was placed in a Boston restaurant for testing.

Commercially, ‘Radarange’ microwave ovens was marketed by Raytheon company in 1954. It was too much large, expensive and rated at 1600 watts. It was practically used in restaurants only. 

They were 5 ½ feet in length, weighed 750 pounds and cost $5000 each unit. Also Magnetron tube got heated whenever used, so it need to be water cooled. There were plumbing installations in each unit for cooling.

In 1967, Amana, a division of Raytheon, introduced its domestic ‘Radarange’ microwave oven, marking the beginning of the use of microwave ovens in home kitchens. 

In succeeding years, Litton and a number of other companies joined the countertop microwave oven market. By 1975, sales of microwave ovens would, for the first time, exceed that of gas stove ranges. America's cooking habits were being drastically changed by the time and energy-saving convenience of the microwave oven.

Although Initial sales of microwave ovens were disappointing due to so many disappointing features but further improvements and refinements with the passage of time produced a light weight, more reliable, less expensive and new air cooled magnetron which required no plumbing system.

An expanding market has produced a style of microwave oven to suit every taste; a size, shape, and colour to fit any kitchen, and a price to please almost every pocketbook.

Industries began using microwaves to dry potato chips and roast coffee beans and peanuts. Meats could be defrosted, precooked and tempered. The microwave oven had become a necessity in the commercial market and more practical uses are being added to it..the list is just endless.

Wednesday, October 15, 2014


Scott was a French Parisian typrsetter, publishing a book on the history of shorthand. Scott apparently thought that sound recording might improve stenography. His aim was to represent sound visually, not record it for playback.

During 1850s  Scott de Martinville  invented a device called as “phonautograph,” which had a barrel-shaped horn attached to a stylus.  Sound waves entering the horn caused the stylus to vibrate, which etched squiggiles onto a sheet of paper covered with a layer of soot from an oil lamp. 

The paper was mounted on a rotating drum that also moved horizontally along its axis as it turned, so the stylus traced a spiral, much like a wax cylinder”

On Dec. 6, 1877 Thomas Edison was the first to record sound successfully on a ‘phonograph’.
This device recorded sound mechanically. As the cylinder rotated at a steady speed and Edison began to recite, “Mary had a little lamb / Its fleece was white as snow…”, his sound wave directed into a horn would vibrate a disk connected to the stylus, in turn embrossing a groove onto the tinfoil that was at some points shallow and at others deep, depending on the strength of the sound.

When he had finished reciting the nursery rhyme, he brought the needle at the beginning of the groove and rotated the cylinder again, the movement of the stylus in the groove caused the disk to vibrate again, thus turning the horn into a speaker reproducing original sound. This device sounded very harsh and not so clear.

During 1880s Alexander Graham Bell began his research on the nature of sound in a laboratory in Washington, D.C. 
In 1881, he designed a device with a wax coated cardboard cylinder called the ‘Graphophone’, an improved form of the phonograph having better sound quality.

The main difference between a phonograph and graphophone was that the graphophone used wax as the recording channel rather than tin foil, and the recording was cut or chiseled into the wax rather than being embossed.
Although Edison is often referred to as the inventor of the gramophone record, but this honour is really due to Emil Berliner.
In the 1890s, Emile Berliner designed a flat recording disc that was an improvement of Thomas Edison’s cylinder design.
Emile used a zinc disc coated with wax to record sound. When the recording was chiseled into the wax, the disc was dipped into an acid solution, which ate away the disc under the groove and etched the recording into the surface of the zinc.  Then the zinc disc was turned into a stamper using an electroplating process.
The final recordings in large number can be produced by pressing the stamper into a ball of vulcanite which is a type of hard rubber.  Emile Berliner named his invention as the ‘gramophone’.

Its volume can be increased by the pressing of tonearm into the grooves hardly. Berliner’s first record had a diameter of 12.5 cm, only half a centimeter larger than the Compact Disc that was to be introduced 95 years later. But Berliner’s disc had a playing time of barely one minute, while today’s CDs can contain around 80 minutes of music.
Emile set up a small recording studio in 1896. Berliner later on switched over to shellac as the material for his records, and this continued to be used for the production of 78 rpm  records until the introduction of the LP (Long Play record) in 1948.

But there was still an era of silent films till the late 1890’s. while many scientists including Edison were  trying to link sound with the silent film images.

 Western Electric introduced electrical recording and playback systems developed at AT&T’s Bell Labs in 1925. It was called the transcription recorder in radio stations. This electrical recording technology given by Western Electric became the basis of talking pictures.

In Oct, 1924, . The Columbia Phonograph Company developed a new device called as ‘Orthophonic’ having sound different from those of recorded by the acoustic process.    
Edison never believed in Berliner’s flat records, and stubbornly continued with his cylinders. Finally Edison also developed a gramophone record with 30 cm Long Play record. It was capable of holding 20 minutes of music per side.
That 12-inch diameter discs had finely spaced grooves and turned at just 33 1/3 rpm. But despite its excellent sound quality this record was not a success, the public instead choosing the 78 rpm shellac records with horizontal (lateral) recording,
The English inventor Oberlin Smith worked out theoretically on the principle of the magnetic tape recorder  in 1888. German scientist Fritz Pfleumer was learning how to apply iron-oxide particles to paper tape for magnetic recording in the early 1930s. He invented magnetic tape for recording sound in 1928. 
Magnetic tape was further developed by the German electronics company AEG, which manufactured the recording machines and BASF (a German chemical company), which manufactured the tape.
Magnetic tape brought revolution in both the radio broadcast and music recording industries. It gave the power to record and re-record sound with minimum loss in quality.

Within a few years of the introduction of the first commercial tape recorder, In 1948, the Ampex 200 model was launched ,which was the first multitrack tape recorder, invented by American musician-inventor Les Paul.

It brought about another technical revolution in the recording industry. Tape made possible the first sound recordings totally created by electronic means,

The compact cassette, also called the audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. The main purpose for its designing was to record dictation but later on it replaced the Stereo 8-track cartridge and reel-to-reel tape recording in most non-professional applications. 

 The area of its usage increased from portable audio to data storage for early microcomputers. Between the early 1970s and the late 1990s, the cassette was one of the two most common formats for prerecorded music.
The Mercury Record Company, a U.S. affiliate of Philips, introduced M.C. (Musicassettes), prerecorded music cassettes, to the U.S. in July 1966.
During the 1980s, the cassette’s acceptance evolved further as a result of portable pocket recorders and high-fidelity (“hi-fi”) players, such as Sony’s Walkman (1979),
Sony’s WM-10 was even smaller than the cassette itself and expanded to hold and play a cassette.

Like the transistor radio in the 1950s and 1960s, the Walkman dominated the portable music market in the 1980s,
The Compact Disc (also known as a CD) is an optical disc used to save digital data. Sony first openly demonstrated an optical digital audio disc in September 1976.
The CD was considered to be the successor of the gramophone record for playing music, rather than first and foremost as a data storage medium

In 1982 First ever album on a CD released by Sony, which was Billy Joel's 52nd Street.
In June 1985, the computer readable CD-ROM (read-only memory), In 1987  The first Video CD (VCD) format created for storing and playing video and audio and,
In 1990, CD-Recordable were introduced, also developed by both Sony and Philips. In 1996, DVD technology hit the world, through the collaboration of leading computer companies such as Sun, Apple, Dell, and many more.
Today, the process of making a recording is separated into tracking, mixing and mastering. Multitrack recording makes it feasible to capture signals from several microphones allowing previously unavailable flexibility in the mixing and mastering stages for editing, level balancing, compressing and limiting, adding effects such as reverberation, equalization, flanging, and much more.


Friday, October 10, 2014


The word ‘Computer’ was first recorded as being used to describe a Human who performed Computations or Calculations during 1613.
Human Computers

As the time past, people realized that machine can do calculations more accurately and more faster and never get tired like humans.

In 1822, Charles Babbage began developing Difference Engine which was considered as first automatic computing engine.
Difference Engine

In 1837, Charles Babbage proposed first general mechanical computer called the Analytical Engine, which contained an Arithmatic Logical Unit (ALU), basic flow control, Integrated memory.

But he could not build it due to funding issues till he was alive. In 1910, Henry Babbage, Charles Babbage’s son, complete a portion of this machine and able to perform basic calculations.

Hollerith's invention, known as the Hollerith desk, consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count (using Pascal's mechanism which we still see in car odometers), and a large wall of dial indicators (a car speedometer is a dial indicator) to display the results of the count.
Hollerith Desk

Z1 was the first electromechanical binary programmable computer created by Zuse in 1936-38.

Turing Machine was proposed by Alan Turing in 1936. It was theoretical generalised computer, composed of a tape on which symbols representing instructions are imprinted. The tape can move forward and backward in the machine, which can read the instructions and write the result output back onto the tape.

Turing Machine

ABC (Atanasoff Berry Computer) was developed by Professor Atanasoff and Graduate student Berry in 1937 till 1942 at Iowa State University. It was the first electrical computer used vacuum tubes for digital computations and had no CPU.
Atanasoff Berry Computer (ABC)

Colossus, also called Mark I, was the first programmable computer developed by Tommy Flowers in 1945 during world war II in England. It was created to help british code breakers to read encrypted German messages.
Colossus Computer

Electromechanical computer Mark I used relays to represent data. Ist calculation was done on May 6, 1949 on Mark I and also it ran the first graphical computer game nicknamed as ‘Baby’.
Earliest all computers used vacuum tubes as switches.

During 1943-1945, ENIAC (Electronic numerical Integrator And Calculator) was built by Professors J.Presper Eckert and John Mauchly at University of Pennsylvania. It occupied about 1800 sq feet of space, weighted 30 tons and used about 18,000 vacuum tubes.

But when ENIAC was ON, 18,000 vacuum tubes generated about 174,000 watts of heat. So it was operated in a specially designed room with heavy duty air conditioning system.
ENIAC could hold 20 numbers at a time. A multiplication that required 6 seconds on Mark I could be performed in 2.8 thousandth of a second on ENIAC.
ENIAC (Electronic numerical Integrator And Calculator)

ENIAC first task was to compute whether it was posiible to build a hydrogen bomb and after using half a million punch cards for 6 weeks, ENIAC declared hydrogen bomb feasible.
But In ENIAC, physical modification of all patch words and switches was required for reprogramming the system. It generally took several days.

Eckert and Mauchly along with mathematician John Von Neumann designed EDVAC (Electronic Discrete Variable Automatic Computer)which pioneered the stored program. Neumann realized program could be represented electronically  just like data.
EDVAC(Electronic Discrete Variable Automatic Computer)

 Ist computer company was Electronic Controls Company founded in 1949 by J. Presper Eckert and John Mauchly and later on it became Eckert-Mauchly Computer Cooperation.
But Mauchly and Eckert’s company fall into financial problems and was sold at loss.

UNIVAC I (Universal Automatic Computer) was the first computer for commercial use in public.

In 1953, Ist Electronic computer was launched by IBM (International Business Machines) named as “IBM 701”.  By 1955 IBM was selling more computers than UNIVAC.
IBM 7090, IBM 360, IBM 370 are mainframe computers.
IBM 7094 Computers

Bell Laborataries invented transistors. Transistors replaced vacuum tubes because of small size, cheaper, less power consumption, fast switching speed.

Assembly language was used like COBOL, ALGOL, SNOBOL, FORTRAN. Around 100 programming languages were developed at that time.

Microprocessor is a computer fabricated on Integrated circuits. 1st microprocessor was developed at Intel in 1971.

It was not Intel company which invented the electronic computer but they firstly succeed in cramming an entire computer on a single chip.

Intel 4004 was the first microprocessor consisted of 2300 transistors and was clocked at 108 MHz.

Intel followed the 4004 with 8008 and 8080 microprocessor.

Intel priced 8080 microprocessor at $360 dollars in competition with IBM’s famous mainframe computer IBM 360 which costs million of dollars.
Altair8800 Computer was the world’s 1st personal computer.
Altair8800 computer

Intel Pentium 4 used in today’s PC is still compatible with Intel 8088 used in IBM’s 1st PC.
In 1981, IBM introduced its 1st Personal Computer.
The computer was code named and referred to as ‘Acorn’ and had 8088 processor, 16 KB of memory, utilized MS-DOS.

The IBM 5100 is the first portable computer, which was released on September 1975. The computer weighed 55 pounds and had a five inch CRT display, tape drive, 1.9MHz PALM processor, and 64KB of RAM.
IBM 5100 Computer

Compaq - In March 1983, Compaq released its first computer and the first 100% IBM compatible computer the "Compaq Portable."
Compaq Portable PC

Dell - In 1985, Dell introduced its first computer, the "Turbo PC."

Hewlett Packard - In 1966, Hewlett Packard released its first general computer, the "HP-2115."

NEC - In 1958, NEC builds its first computer the "NEAC 1101."

Tuesday, October 7, 2014


Today's bicycles have come through a long way of their humble beginnings as novelty vehicles pushed along with one's feet. Time and technology have produced a series of bicycle models with more and more improvements. Some meet very specific needs, while others are more suited to general riding. 
 The first bicycles were made from wood, but today's bikes and their components are made from any number of materials like Steel, aluminium, titanium, and carbon fibre all used to create bicycle frames and components.
Todays bicycle consists basically of a frame, two wheels, gearing, handlebars and a saddle. Depending upon the brand and the type, they can vary in their designs, but generally they all are same.
Now let us have an overview how Bicycle was invented and how many changes were made to have the current safe, comfortable and speedy bicycles.

When bicycle was invented, it brought a major leap in technology. People did not have to expend on horses and on carts. New designs  got different names in different countries like Draisienne, velocipede, penny farthings, bicycle etc.

Celerifere was the earliest structure of the bicycle that looks like a wooden scooter.
It was invented by Comte Mede De Sivrac of France in 1790.

In 1817, Baron Von Drais invented a device with a steering bar attached to the front wheel. This was known as “Draisienne” or the “Hobby Horse”.
It was completely made up of woods having two wheels of same size, weighted 22kg and no pedal system was there.

It was moved by propelling the feet against the ground to roll it forward just like a gliding walk.
Kirkpatrick Macmillan, a blacksmith from Scotland invented new structure of bicycle with foot pedals in front wheel in 1830’s but he never patented it.

Pierre and Ernest Michaux, a father and son team of carriage makers developed a new bicycle with pedals applied to the front wheel. Thus Pedalling made it easier to riders to propel the bicycle with speed. This machine was known as “Velocipede” or Fast Foot. We can say,  ‘Velocipede’ was the mechanical ancestor of bicycles.

Due to its rigid frame and iron banded wheels, it gives a bone shaking experience to riders, that’s why; Velocipede earned the name “Bone Shaker” in England.

In 1870, Use of metal frames, due to advancement in metallurgy, reduced the weight of frames and now the design was more elegant and sleeker. But still no freewheeling mechanism because of the front wheel pedal attachment.

During 1870’s, it was realized that larger the front wheel, more will be the distance it covers. So High wheel bicycle were invented with a large front wheel and a small rear wheel. This bicycle provide a much smoother ride than its predecessor because of the solid rubber tyres and long spokes of large front wheel.

But the problem of “taking a head” was quite common in high wheel bicycles. Because the rider used to very much above the ground, it leads to imbalance of centre of gravity when bicycle was suddenly stopped by the rider. Rider’s legs caught underneath the handlebars and the whole bicycle rolled on front axle and the rider falls abruptly on his head.

James starley in Coventry added tangent spokes and the mountain step to his famous bicycle called ”Ariel”. Front wheel diameter could be adjusted depending on the rider’s leg length. This type of bicycle was called as “ordinary” and later nick named as “Penny farthing” in England.

A “penny” represents the front wheel and a coin smaller in size and value, the “farthing” represents the rear wheel.

Elderly gentleman did not use the high wheel bicycle due to the problem of imbalancing. They  preferred the more stable tricycles or quaderacycles. Queen Victoria owned Staley’s “Royal Salvo” in England.

Although Harry John Lawson invented real chain drive ( a chain with sprockets ) bicycle in 1879 but still had a huge front wheel and small rear wheel , so it again failed in market.

John Kemp Starley, James Starley’s nephew , developed the first successful “Safety bicycle”  ,the “Rover” in 1885 with steerable front wheel , almost equal sized wheel and a chain drive to rear wheel but he never patented it. This bicycle have the same speed through gear ratios just like a one wheel circumference for every pedal turn in the huge high wheel bicycle .

But it still had hard rubber tyres so the ride was still uncomfortable. Dunlop , an Irish veterinarian, applied pneumatic tyres to the bicycles for his son to give a comfortable ride.  Now in this pneumatic tyred structure, comfort and safety was available in a single package.

In 1898, Yale used a shaft drive to dispense with the chain.

It was the practical investment for working persons as means of transportation.

Bicycling was so popular in the 1880s and 1890s that cyclists formed the league of American Wheelman. The League lobbied for better roads, literally paving the road for the automobile.

Monday, October 6, 2014


Whenever anyone talks about Clock the very first thing comes in our mind is that it is a device used to measure time but hardly we thought about how it was invented and what was the reason that such a device was required to be designed. Let’s have a view over this.

The clock is one of the oldest human inventions. Earlier time was measured in terms of natural units. The basic need to develop such a device was to consistantly measure intervals of time shorter than the natural units: the day, the month or the year. Different peoples in different countries develop different time measurement device according to their own opinions. Following are some ancient clocks used in the past.


1. Sundial, an early clock, relies on shadows to provide good estimate of the hour on a sunny day.

2. In common sundials designs such as horizontal sundial, the sun casts a shadow from its style onto a surface marked with line indicating the hours of the day.

(Style is a time telling edge of the a thin cylindrical rod)

3. All sundials must be aligned with their styles parallel to the axis of earth's rotation to tell correct time.

4. Sundials cannot be used during cloudy weather or at night and also requires recalibration as the season changes due to change in direction of sun.


1. Candle clocks were mostly used in china, Japan, England and Iraq.

2. It is a thin long candle with evenly spaced markings (usually with numbers).

3. When the candle is burnt, it indicates what time it was, with the markings made on it.

4. Here observer initially would have to know how long it will take to burn from one marking to next, to know the exact time.

5. The most sophisticated candle clock known to date was those of Al-Jaziri in 1206.


1. The incense clock was invented in China between the years of 960-1279 and was very popular in Eastern cultures.

2. Burning incense was used to measure time, but there were many types.

3. Somewhere Colour of the smoke from the burning incense was used to know a period of time, as the colour of the smoke gets changed after a known passage of time.

4. Some incense clocks used smell to show the passing of time. They would be divided into sections of different smells, and when the observer noticed a particular smell, they could determine what time it was.

5. Some incense clocks would burn underneath of threads with weights attached. After a certain amount of time had passed, the thread was burnt due to the burning fire, causing the weight to drop onto a gong below. This was an “alarm” for the person who wanted to know what time it was.


1. It is also known by the name, Sand Glass, Sand Timer, Sand Watch or Sand Clock.

2. It has two connected vertical glass bulbs allowing a regulated trickle of material from top to bottom.

3. Once the top bulb is empty, it indicates an hour, that's why called as Hour glass. Then Sand glass is inverted to begin time again.


1. A water clock, also known as a clepsydra uses flow of water for time measurement.

2. It was originated in medieval Europe. Greeks began using them around 325 BC and also called as "Water Thieves".

3. There are two types of water clocks: inflow and outflow.

4. In an outflow water clock, a container is filled with water, and the water is drained slowly and evenly out of the container. This container has markings which are used to know the passage of time. As the water leaves the container, an observer can see where the water is level with the lines and tell how much time has passed.

5. Inflow water clock works also works basically the same way, except instead of water flowing out of the container, the water is filling up the marked container. As the container fills, the observer can see where the water meets the lines and tell how much time has passed.


1. Mechanical clocks tell time using gears. They have two important parts: a mainspring and a pendulum.

2. Mechanical clocks are wound with a key, and this tightens the mainspring. As the mainspring unwinds, its energy turns gears which cause the hands to move.

3. The pendulum keeps time and ensures that the gears move at the right pace: second by second.

4. Instead of a mainspring, some mechanical clocks have weights that pull the gears at the right pace. Mechanical clocks do not need electricity to operate. They can run off of the energy generated by their springs and weights.


1. During the later middle Ages, Crude wheel clocks came into use. Such clocks were driven by weights.

2. The principle of Pendulum clock was first given by Galileo but Pendulum clock was constructed by Christian Huygens in 1657.

3. In 1583, Galileo is said to have made his discovery by watching a lamp swinging from the roof of the Cathedral of Pisa and timing the oscillations by the beats of his pulse.

4. He found that a Pendulum of given length makes the same number of swings in a given time, no matter whether the breadth of the swing be large or small.

5. Galileo designed the Pendulum clock but could not construct it because he died before he could complete it.

6. The Pendulum clock was later invented by Christian Huygens in 1657.

7. In this Pendulum clock, an "escapement" allowed the hands of the clock to move an exact amount for each swing of the Pendulum. It kept time accurate with sun and stars.


1. Quartz clocks operate using the mineral quartz inside of a clock to keep time.

2. Like mechanical clocks, quartz clocks still use gears to count time, but they are electrical.

3. The mineral quartz is piezoelectric. This means that when a quartz crystal is squeezed, it generates a very small current of electricity. This also means that when electricity is passed through the quartz crystal, it vibrates.

4. Quartz crystals vibrate at the same frequency, meaning they shake the same number of times each second. Quartz crystals vibrate exactly 32,768 times each second!

All quartz clocks contain a battery to vibrate the quartz crystal and a circuit to count how many times the crystal has shaken.

5. The circuit then uses this information to create regular pulses of electricity. It generates one pulse every second. These pulses then make the gears of the clock move (if it is a mechanical clock) or power a digital display (if it is a digital clock). The quartz crystal in a quartz clock helps keep the clock accurate.