College Level

At the end of the 1960s, Intel's Ted Hoff (b. 1937) was asked to design several different calculators for a Japanese client. The traditional way would have been to develop several different integrated circuits—silicon chips—to do the work. Even though these were small enough to be put into handheld calculators, programmable computers, which could do a variety of jobs, were still huge devices. Combining the small size of integrated circuits with the power of programmable computers was an inevitable idea. Hoff decided that he would make a single integrated circuit that could be programmed to do many different things. Joined by fellow engineers Stan Mazor (b. 1941) and Federico Faggin (b. 1941), Hoff squeezed an entire computer onto a single silicon chip, pairing it with a small memory to give it its instructions. His range of calculators all used the same chip, but each one had different instructions to instruct more...

“... if you are not working on important things, you are wasting time." Dean Kamert The insulin pump is a small, battery-powered device that releases varying amounts of insulin into the bloodstream of diabetics. Diabetes is a disease that affects the body's ability to break down sugar, caused by an absence or insensitivity to the hormone insulin. Until the invention of the insulin pump, the only way for diabetics to control their disease was to inject themselves daily with insulin. The first insulin pump was invented by Dr. Arnold Kadish in the 1960s, but it was so large it had to be worn like a backpack. While Dean Kamen (b. 1951) was at college, his brother, then a medical student , approached him with a problem. He complained that there was no way to provide patients with steady doses of drugs, such as insulin. In response, Kamen constructed a circuit more...

"It [radiant matter] is projected with great velocity from the negative pole." William Crookes, English chemist and physicist The mid- to late-1800s was a period of scientific revolution with physical processes such as electricity beginning to reveal their secrets. Early investigations into electricity led to the development of the cathode ray tube, which would eventually lead to the discovery of the electron, as well as to the invention of television. Michael Faraday (1791-1867) noticed that after removing most of the air in a glass tube containing a cathode and anode, a faint glow could be seen between the positive and negative electrodes. Faraday's work was limited initially by the inability to create more than a partial vacuum. Around 1855 German scientists Heinrich Geissler and Julius Plucker improved vacuum technology and were able to remove more of the airfrom inside such a tube. With the improved vacuum, Plucker was able to more...

A sword consists of a blade and a handle, which is itself made up of a hilt, or grip, and a pommel, or counterweight. A sword blade has one or two edges for striking and cutting, and a point for thrusting. The word "sword" comes from the Old English sweord, meaning to wound or hurt. Humans developed weapons from sharpened flint tools, and in the Bronze Age short-bladed weapons such as daggers were used. It was then impractical to make bronze swords more than 3 feet (90 cm) long, but with the development of smelting technology and stronger alloys, longer iron swords became possible from about 1500 B.C.E. The Chinese single-edged steel sword appeared in the third century B.C.E. By Roman times the hilt was distinct from the short, flat blade, and by the European Middle Ages the sword had acquired its main basic shape and a variety of designs more...

"The object of my invention adapt it to sweeping carpets and floors with uneven surfaces..." Melville Bissell In the nineteenth century, the large Turkish or Axminster carpets that covered floors were not easily cleaned. They had to be taken outside and beaten vigorously with a rug beater to remove the dust. American Melville Bissell (1843-1889) and his wife Anna noticed that the dust in their carpets irritated her and adversely affected his health. To alleviate the dust problem, Melville designed a long-handled carpet sweeper with rotating bristles that bent as they scooped up dirt from a carpet, then flicked it into a compartment Inside the device. The rotation was powered by the sweeper's movement across the floor, and the head could be adjusted to clean bare floors, carpets, rugs, and uneven surfaces. News of the Bissell sweeper spread. Local women began to manufacture the bristles at home and the sweepers more...

Although hearing aids have probably been around for centuries, they are first mentioned in Giambattista della Porta's Magia Naturalis (1598). These early devices were made from wood and were carved to resemble the ears of anil-mils known to have acute hearing. By the late 1700s, ear trumpets were widely available in an array of different shapes, sizes, and materials. These devices all served to passively gather sound waves and direct them to the ear canal. However, in 1819 F.C. Rein made an acoustic throne for King Goa of Portugal. It had carved lions' heads for arm rests and concealed in the heads were resonating chambers that led to a hearing tube by the king's head. In the 1890s there were numerous attempts to develop a powered hearing aid, using the recently invented storage battery. The first commercially successful powered hearing aid was the "Akoulallion" developed in 1898 by Dr. Miller more...

“Change is inevitable—except from a vending machine." Robert C. Gallagher The concept for a vending machine actually dates back to ancient Greece, when the great experimenter, Hero of Alexandria, had the simple idea for a device that accepted a coin and dispensed holy water. The weight of the coin tipped a balance that opened a valve, letting water out until the coin slipped from the balance pan and a counterweight returned the mechanism and closed the valve. This neat idea formed the basis for the modern vending machine. Various contraptions for vending began to be produced in the 1800s, including some designed to get around the legal ramifications of selling illicit merchandise, such as the machines designed by Robert Carlile for selling banned books. Another example is Simeon Denham's design for a machine to dispense postage stamps for a penny.      But it is unclear whether this machine ever more...

"One may sometimes tell a lie, but the grimace that accompanies it tells the truth." Friedrich Nietzsche, German philosopher Some lies roll off the tongue all too easily, while others can put the body under noticeable stress, inducing sweating palms, nervous twitches, contorted voices, and pounding heartbeats. Thanks to John Augustus Larson (1892-1983), signals such as these can also help to incriminate the sneakiest of liars. Larson, a medical student at the University of California, invented the polygraph in 1921 and, In doing so, introduced one of the most contentious tools ever brought to the police officer's locker. Larson's lie detector worked by continuously and simultaneously monitoring physical responses such as changes to blood pressure, pulse rate, and respiration. Unfortunately, there is no known lie hormone that is secreted during acts of deception, and as the responses under surveillance can be triggered by any stressful situation or indeed be suppressed more...

Before the arrival of the electric iron, various methods were used to smooth out washed and wrinkled clothes. Charcoal-filled pans dating back to ancient China lasted through to the seventeenth century when they were replaced by cast iron flat irons, which were heated up in open fires. By the late nineteenth century, flat irons were being heated by a range of fuels including kerosene and animal oils. But ironing was a sweaty, tiring, and dirty task typically involving a hot coal stove and numerous flat irons, which required continuous heating. With the coming of electricity it was inevitable that someone would spot an opportunity. Henry W. Seely an American inventor based in New York, was the first to develop and patent an electric iron in 1882. The electric iron uses resistive heating—heat produced by resistance to an electric current. This is used to warm a metal hot plate, today made more...

The modern system of automobile brakes was patented in 1902 by British car manufacturer Frederick William Lanchester (1868-1946). He took the disk brakes then available and radically improved their design. But, competition with the new drum brakes meant that disk brakes took almost fifty years to become a reality on a mass-produced car, and another five years before the concept became widespread. Lanchester and his three brothers formed the Lanchester Engine Company in 1899. He had been designing cars and engines since 1889, and had built the United Kingdom's first four-wheel drive car in 1895. In 1902 their latest prototype, which contained a ten horse-powered, twin cylinder engine, was fitted with the new system of disk brakes. Disk brakes slow a car by removing energy from the rotating wheel; brake pads squeeze both sides of the rotor connected to the wheel. The friction of this generates heat, which escapes via more...