"After months of frustration, we had grown used to seeing blobs of resin caked on the mold..." Nathaniel Wyeth The humble plastic bottle is now one of the most commonly recycled household objects. But it was the product's cheapness and durability that led to its popularity over glass bottles. Nathaniel Wyeth (1911- 1990), a U.S. engineer, worked on the invention for almost a decade. When he asked a colleague if plastic could be used to store carbonated beverages such as Coca Cola, he was told that they would explode. A series of early experiments proved that carbonated beverages caused the plastic to expand. Obviously, the plastic was too weak, but the plastic could be strengthened if the long strands of molecules that form plastic were woven together. Wyeth knew that nylon gets stronger when its molecules are stretched and aligned, and developed a pre-formed mold that forced the nylon threads more...

"Sunglow, unmellow yellow, atomic tangerine, purple pizzazz, razzle dazzle rose, neon carrot...” Names of crayon colors added to the 1990 box They have brought color and creativity to generations of children across the world, but the crayon family began with just one color, black. Originally based on a mixture of charcoal and oil, the oil was soon replaced with wax to make the crayon stronger and easier to hold. American cousins Edwin Binney (1866-1934) and Harold Smith (1860-1931) had a company that sold paint pigments—red for painting barns and black for car tires. In 1900 they began to make pencils and came up with the useful idea of dustless chalk for teachers. While touring schools with these products, the cousins spotted a gap in the market for a new drawing and writing implement. They set about making a safe, nontoxic toy for children and, in 1903, the first box of more...

In 1908 physicists Hans Geiger (1882-1945) and Ernest Rutherford (1871-1937) were observing ionized helium atoms at Manchester University and wanted to confirm the data from their scintillation crystal counters. Their new "Geiger" counter consisted of a high-voltage wire running along the central axis of a sealed brass cylindrical tube containing low-pressure carbon dioxide. When charged particles entered through a window in the chamber they collided with and ionized CO2 molecules leading to a voltage change on the central wire that was registered on a galvanometer. A count rate of five to ten per minute could be registered. Soon more sophisticated detectors using helium gas and a photographic voltage registration were introduced, increasing the count rate to about a thousand per minute. In 1928 improvements made in the electrical characteristics by Walther Muller (one of Geiger's PhD students) enabled the instrument to detect electrons. The main problem was the recovery time—the more...

Ram Krishna Paramhans was India's great spiritual leader who is remembered for his valuable teachings based on humanity. He was primarily a religious reformer. He was a deeply spiritual man who believed that the basic meaning of all religions was the same. Ram Krishna Paramhans was born on February 18, 1836 in a poor orthodox Brahmin family in a remote village of  Bengal. His original name was Gadadhar. He had immense spiritual potential from his very childhood. Even at the age of five, he had a burning desire to study the lives of saints. As he grew up he wished to have a vision of Goddess Kali, whom he considered as the Devine Mother. As his realization deepend the vision of the Devine Mother became luminous while he was the priest of Dakshineshwar Temple in Kolkata. He would enter into deep trances and loose consciousness just to seek the truth. more...

"While fancy, like the finger of a clock, runs the great circuit, and is still at home." William Cowper,"The Winter Evening"(1785) Around 1602 Galileo Galilei noticed that the swing period of a pendulum was nearly independent of the amplitude of the oscillation, and this became the most important discovery in the history of horology. In 1656 Dutch mathematician and astronomer Christiaan Huygens (1629-1695) was the first to use a pendulum as a regulating oscillator in a clock. The swing period of a pendulum is only a function of its length and the local gravitational field, unlike the verge and balance (foliot) oscillator, which it replaced, which had an oscillation period that depended on the force exerted by the driving spring. Within years of Huygens's discovery weight-driven pendulum clocks were appearing all over Europe. To provide a sufficient distance for the weights to fall, and to accommodate a reasonably long pendulum—a more...

"[Engine control] requires an intelligent man, an honest man, a sober man, a steady man..." Isambard Kingdom Brunei, engineer The steam in early steam engines was used only once; after it had pushed back the piston it was discharged into the atmosphere, A more efficient process allowed the steam to expand in two or more stages. These "compound" engines had two or more cylinders. After the steam had been expanded in the high-pressure cylinder the exhaust steam was then used to push back the piston of a following, larger-circumference, low-pressure cylinder. The two pistons were connected with cranks that enabled them to work at the required different phases. With correct size scaling, the power output per cylinder could be equalized, and the engine ran smoothly. As these systems were rather complicated, theywere mainly used in industrial and marine engines. Some compound railway locomotives were built, but the tough operating conditions more...

Distance education is a new trend of education which generally takes place when a teacher and student (s) are not face to face but are separated by physical distance and various electronic media are used to bridge the instructional gap. Before ten years this system or trend was not thought a goal means of education because 'to take degree' was not the sole aim of a student. Instead people thought that regular classes provided real knowledge to the students and therefore there should not exist any alternative of it. But with the progress of science electronic media, new electronic equipment, the situation has been changed. Through TV. Educational programmes, the correspondence education can be made to be understood in better way. Research comparing distance education to traditional face to face instruction indicates that teaching and studying at a distance can be as effective as traditional instruction, when the method and more...

“I see nothing in space as promising as the view from a Ferns wheel.” E.B. White, writer How do you outdo the Eiffel Tower? This was the problem facing the organizers of the Chicago World's Fair of 1893. The solution was presented by George Ferris (1859-1896), who submitted details right down to ticket prices. Ferris was a civil engineer with an interest in railroads and bridge building. His design was for a wheel, 262 feet (80 m) tall, capable of carrying 2,000 people up for a view of the whole fair. Smaller, wooden "pleasure wheels" had already appeared around the world, but this design was on a much grander scale. However, the fair organizers thought it could not be done and rejected Ferris. Not a man to be easily deterred, he returned after convincing fellow engineers to endorse the design and local investors to cover the $400,000 cost. This time more...

Mobile phone is the latest and wonderful invention. This instrument is very small in size but performs very big functions. It is in fact, an improvised version of the landline telephone and enables us to talk to anybody in any part of the world. It can be carried anywhere wherever a person may go. It makes conversation possible whether we are travelling by car, bus, train or aeroplane. This phone has received tremendous response from people all over the world. It is used by all people, whether rich or poor, in order to remain in constant touch with the other people associated to them. Almost all cities of the world are connected with mobile network. A mobile phone has played a very vital role, especially during an emergency such as an accident, a robbery, a murder or sudden serious illness. It has revolutionised the way we communicate. Today we find more...

Thermostats control the temperature of a system—such as an oven, car engine, or room—so that it remains close to a preset value. The control is achieved by means of a temperature-sensitive switch that operates heating or cooling devices. Many of these switches are activated by monitoring the expansion of metals, waxes, or gases. More recently, thermostatic devices have relied on thermistors in electrical circuits. The thermistor is usually a ceramic or polymer electrical resistance that changes its value significantly as a function of temperature. Thermistors were patented by Samuel Ruben in 1930. Dr. Andrew Ure (1778-1857) was a Scottish medic and chemist who was also greatly interested in the factory system, free trade, and steam-driven machines. Realizing that textile mills needed constant temperatures to ensure uniformity in product manufacture, Ure patented a thermostat for this purpose. This was not an entirely new device. The Dutchman Cornelis Drebbel (1572-1633) had used more...