Primary School Level

"If the only tool you have is a hammer, you tend to see every problem as a nail." Abraham Maslow, psychologist The use of hand tools by humans has undeniably been a major factor in our evolution from hunter-gatherers to builders of civilizations. On many occasions a new design of tool has come at just the right time to add a boost of acceleration to the history of our technology. The invention of the pneumatic hammer was one of those very events. Charles Brady King (1869-1957) had an eclectic range of interests. He considered himself a mystic, as well as a musician, artist, poet, and architect. He also had a degree in mechanical engineering from Cornell University, New York. His invention of the pneumatic hammer was perfectly timed. The 1890s were a time of rapid growth in construction, shipbuilding, mining, and the new automotive industry. Any invention that increased the more...

During the American gold rush (1848-1855), people flocked from all over the world to California with dreams of finding great wealth. Lester Pelton (1829- 1908) of Ohio was one of these migrants, but it was not in gold that he found success. It was with his free- jet water turbine, which he first patented in 1880, that he found fame and fortune. Gold mining was becoming a large-scale industry and required ever-increasing amounts of power. As firewood supplies dwindled, steam power became very expensive and mining companies looked for an alternative energy source in the creeks and waterfalls surrounding the mines. In 1866 Samuel Knight invented a water turbine that replaced the paddles of water wheels—like those used in rivers to power flour mills—with cups to catch jets of water directed from above. While watching a misaligned turbine, Pelton noticed that the water ran down the edge of the cup more...

"Will you have some microbe? ... The Microbe alone is true, and Pasteur is its prophet." French journalist mocking Pasteur in 1881 In the 1870s, French microbiologist Louis Pasteur (1822-95) was still trying to disprove criticism of his germ theory. He had reported that boiled fluids, such as broth and urine, do not support bacterial growth if kept free of contamination. The British physician Harry Bastian, an outspoken critic, countered that boiled urine could indeed grow bacteria. Pasteur realized that to prove his germ theory, he needed to achieve temperatures greater than 212°F (100°C) and charged French microbiologist Charles Chamberland (1851- 1908) with creating such a device. Chamberland knew that if water were boiled under pressure, it could reach 250°F (121°C). Fifteen minutes at this temperature killed all known bacteria. He devised an autoclave, or "self lock," in 1879, for sterilizing surgical instruments. Chamberland's device was based on the 1679 more...

"When you hunt... you may succeed or not. When you open the fridge, you succeed [all] the time." Nora Volkow, National Institute on Drug Abuse The refrigerator is one of the key inventions of the twentieth century. Its use in food storage is vital, slowing the development of bacteria and keeping food edible for much longer. Before its invention, the only source of cold was blocks of ice, which could be bought in some places and used with a cool-box. Most homes had no means of chilling food. Baltzar von Platen (1898-1984) and Carl Munters (1897-1989) were; students at the Royal Institute of Technology in Stockholm, Sweden, when they collectively invented and developed the gas absorption refrigerator. Unlike modern fridges, the invention did not require electricity driving a compressor, but relied instead upon an ingenious process whereby a refrigerant gas is put through a series of changes of state. In more...

"Applications of science to warfare and materialistic enjoyment mil be the downfall of mankind^ Edouard Branly The science behind the coherer had long been observed by various people before anybody actually managed to put it to any practical use. The effects of electrical charge on small specks of certain matter,' such as dust, was noted in around 1850 by a man named Guitard. He spotted that when dusty air was electrified, the particles of dust would gather together to form a sort of stringed formation. It was not until 1890 that Edouard Branly (1844-1940) found a way for this unusual phenomenon to be exploited. Experimenting with thin pieces of platinum film on glass, Branly discovered that there was a massive variation in the film's electrical resistance when it was subjected to electromagnetic waves (known at the time as Hertzian waves, known today more commonly as radio waves). This discovery led more...

The first job German-American statistician Herman Hollerith (1869-1929) had was with the U.S. Census Bureau. His task was to collate information gained from the 1880 census by hand and he quickly realized that the process would be much faster and less prone to error if it was automated. Trying to work out a solution to the problem, he arrived at the idea for a system based on punchcards while observing a bus conductor punch holes in tickets. He filed his first patent in 1884. The punchcards were not entirely novel—the French weaver Joseph-Marie Jacquard had invented a way of controlling the warp and weft on his loom by patterns of holes in cards—but Hollerith's design for a tabulator and sorter were original. The information was read from each card using an array of spring-mounted brass pins that formed an electrical connection through any holes in the card. The tabulator then more...

"There is no lighter burden, nor more agreeable, than a pen" Petrarch, poet John J. Laud's invention, the ballpoint pen, was far from perfect. It leaked and smudged documents and was too crude for standard letter-writing. Nevertheless, Loud—a leather tanner from Massachusetts who wanted something that could write on leather and wood—patented his new writing instrument on October 30,. 1888. With a tiny steel ball bearing in the nib and three smaller balls aligned above it to try to regulate ink flow, all refreshed with ink from a reservoir above. Loud had invented the world's  first pen that did not constantly require dipping or refilling. However, Loud was unable to control the flow of ink, which contributed to the pen never being sold commercially. If the ink were too thin the pen would leak; if it were too thick, it would clog. Depending on the temperature, the pen would sometimes more...

In 1934, Glen Joseph, a chemist at the California Fruit Growers Exchange laboratory, was trying to accurately measure acidity in citrus fruit products. The most common method at the time for testing pH, a measure of acidity or alkalinity of a substance, was to use litmus paper. Litmus paper turns different colors depending on the acidity of a substance. This was of no use to Joseph, however, because the sulfur dioxide used as a preservative in citrus Juice bleaches out the paper. Joseph tried using glass electrodes, but these were susceptible to breakage and gave a very weak signal. He finally called upon his old classmate Arnold Beckman (1900-2004), then employed as a professor at Caltech, who told Joseph that he needed to use vacuum tubes. Beckman later ended up making the instrument himself. The instrument worked, so well that Joseph soon ordered another one for his laboratory. Beckman realized more...

Prior to videotape, film was the only practical medium via which television programs could be recorded, which was a problem for U.S. television executives whose audiences were spread across several time zones. For a viewer on the East Coast to see a show on the same night as someone on the West Coast, the live broadcast had to be filmed, sent for processing, returned to the studio, and then retransmitted a few hours later. A team at Ampex, including the enemy of hiss, Ray Dolby, and led by Charles Paulson Ginsburg (1920- 1992), developed the first solution in the form of a Videotape Recorder (VTR), a unit that could capture live images from television cameras, convert them into electrical signals, and save the information onto magnetic tape. In an audiotape recorder, the information is recorded linearly, the tape traveling past the record head at, for example, 3-7 inches (7.6-17.7 cm) more...

Between 1882 and 1890, construction of one of the most ambitious engineering projects of the time took place near Edinburgh, Scotland. The project was to create a railway bridge that would span the Firth of Forth, one of Scotland's major tributaries, and connect the northeast and southeast of the country. The men who stepped forward to take up this challenge were Benjamin Baker (1840-1907) and John Fowler (1817-1898). Artist William Morris described it as "the supremest specimen of all ugliness," but their design became a national icon and set a new standard in engineering. Baker and Fowler were chosen in 1882 to replace the previous designer of the Forth Rail Bridge, Sir Thomas Bouch, when one of his projects, the Tay Bridge, collapsed in 1879 killing seventy-five people. Baker and Fowler had an established pedigree of engineering in Victorian Britain, their achievements including the construction of the Metropolitan Line, the more...