My Science School

In 1774, the English chemist Joseph Priestley announced that he had discovered ar element within the air. Previously it had been thought that air itself was an element. However, Priestley’s achievement is an example of something that happens quite frequently in science. Although Priestley undoubtedly did discover the presence of oxygen, he was not the first to do so. A Swedish chemist called Carl Scheele had discovered it some months before, and it was not until some months later that a French chemist, Antoine Lavoisier, used Priestley's work to explain what oxygen is and its importance in respiration and combustion. He also gave oxygen its name. The sharing of scientific knowledge moves our understanding of the world forward. No one person can put together all the pieces of the jigsaw puzzle.

Priestley entered the service of the Earl of Shelburne in 1773 and it was while he was in this service that he discovered oxygen. In a classic series of experiments he used his 12inch "burning lens" to heat up mercuric oxide and observed that a most remarkable gas was emitted. In his paper published in the Philosophical Transactions of the Royal Society in 1775 he refers to the gas as follows: "this air is of exalted nature…A candle burned in this air with an amazing strength of flame; and a bit of red hot wood crackled and burned with a prodigious rapidity, exhibiting an appearance something like that of iron glowing with a white heat, and throwing sparks in all directions. But to complete the proof of the superior quality of this air, I introduced a mouse into it; and in a quantity in which, had it been common air, it would have died in about a quarter of an hour; it lived at two different times, a whole hour, and was taken out quite vigorous."

Although oxygen was his most important discovery, Priestley also described the isolation and identification of other gases such as ammonia, sulphur dioxide, nitrous oxide and nitrogen dioxide.

The Leeds Library holds important archival material on Priestley's time there. It was while he was in Leeds that he began his most important scientific researches namely those connected with the nature and properties of gases. A bizarre consequence of this is that Priestley can claim to be the father of the soft drinks industry. He found a technique for dissolving carbon dioxide in water to produce a pleasant "fizzy" taste. Over a hundred years later Mr Bowler of Bath benefited from this when he formed his soft drinks industry.

Priestley should be included in any pantheon of scientists. The bicentenary of his death is an opportune time to reassess his life and work and several events are planned during the year. He possessed enormous scientific skills and originality of thought as well as having the courage to promote unpopular views. He was a man of rare insight and talent.

Sir Edmond Halley’s name is remembered because he was the first person to predict that the comet he saw in 1682 followed a path that would bring it within sight of the Earth again in 1758. Unfortunately, he was no longer alive at that date to see his prediction come true, but his achievement was recognized and his name attached to the comet ever afterwards. In fact, the comet can be seen from Earth every 75-79 years. Its appearance was first recorded by Chinese astronomers in 240BC. The comet, still an unexpected visitor, also appeared in 1066 and was embroidered onto the Bayeux Tapestry, which records the Norman invasion of England.

Edmond (or Edmund) Halley was an English scientist best known for predicting the orbit of the comet that was later named after him. Though he is remembered foremost as an astronomer, he also made significant discoveries in the fields of geophysics, mathematics, meteorology and physics.           

In 1704, Halley was appointed the Savilian professor of geometry at Oxford. Continuing his work in observational astronomy, Halley published "A Synopsis of the Astronomy of Comets" in 1705. In this work, he showed that comet sightings of 1456, 1531, 1607 and 1682 were so similar that they must have been the same comet returning. He predicted that it would return in 1758.

In 1716, Halley devised a method for observing transits of Venus across the disk of the sun in order to determine the distance of Earth from the sun. He also proposed two types of diving bells for exploring underwater. In 1718, by comparing star positions with data recorded by the Greek philosopher Ptolemy, he deduced the motion of stars.

In 1720, Halley succeeded Flamsteed as Astronomer Royal. He continued to make observations, such as timing the transits of the moon across the meridian, which he hoped would eventually be useful in determining longitude at sea.

Halley died Jan. 14, 1742, in Greenwich, England. He did not survive to see the return of what later was named Halley's Comet, on Christmas Day in 1758.

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At one time tens or even hundreds of years might have passed between a scientist’s discovery of a potentially useful fact or method and its use by a wide range of other people. Nowadays, the process is much quicker. This is partly because research is often very expensive and there is pressure to find a commercial use for an invention to help to pay for new research. Modem methods of mass production and global advertising also mean that new products can become popular very quickly.

Hundreds of years ago, news about new products travelled very slowly. Today, advertising is aimed at individual markets and ensures that as many people as possible are aware of what is available.

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Galileo Galilei (1564-1642) was an Italian scientist who worked on many mechanical problems but is perhaps best known for his astronomical observations. These supported the ideas developed by Nicholas Copernicus (1473-1543), a Polish scientist. He claimed that rather than the Sun orbiting the Earth, the Earth orbits the Sun. This idea went against the teachings of the Church, so Copernicus did not tell many people about it. Indeed, when Galileo spoke out in its support, he was put on trial and forced to withdraw his claim. Even today, scientific discoveries are not always popular when they go against long-held beliefs.

Italian astronomer Galileo Galilei provided a number of scientific insights that laid the foundation for future scientists. His investigation of the laws of motion and improvements on the telescope helped further the understanding of the world and universe around him. Both led him to question the current belief of the time — that all things revolved around the Earth.

The Ancient Greek philosopher, Aristotle, taught that heavier objects fall faster than lighter ones, a belief still held in Galileo's lifetime. But Galileo wasn't convinced. Experimenting with balls of different sizes and weights, he rolled them down ramps with various inclinations. His experiments revealed that all of the balls boasted the same acceleration independent of their mass. He also demonstrated that objects thrown in the air travel along a parabola.

At the same time, Galileo worked with pendulums. In his life, accurate timekeeping was virtually nonexistent. Galileo observed, however, that the steady motion of a pendulum could improve this. In 1602, he determined that the time it takes a pendulum to swing back and forth does not depend on the arc of the swing. Near the end of his lifetime, Galileo designed the first pendulum clock.

Galileo is often incorrectly credited with the creation of a telescope. (Hans Lippershey applied for the first patent in 1608, but others may have beaten him to the actual invention.) Instead, he significantly improved upon them. In 1609, he first learned of the existence of the spyglass, which excited him. He began to experiment with telescope-making, going so far as to grind and polish his own lenses. His telescope allowed him to see with a magnification of eight or nine times. In comparison, spyglasses of the day only provided a magnification of three.

It wasn't long before Galileo turned his telescope to the heavens. He was the first to see craters on the moon, he discovered sunspots, and he tracked the phases of Venus. The rings of Saturn puzzled him, appearing as lobes and vanishing when they were edge-on — but he saw them, which was more than can be said of his contemporaries.

The spinning jenny was one of the inventions that revolutionized textile production in the eighteenth century. For thousands of years, spinners were able to produce only one thread at a time, using devices such as spinning wheels. Then in 1764, James Hargreaves, an English weaver, invented a machine that could be operated by one person but spin several threads at the same time.

During the 1700s, a number of inventions set the stage for an industrial revolution in weaving. Among them were the flying shuttle, the spinning jenny, the spinning frame, and the cotton gin. Together, these new tools allowed for the handling of large quantities of harvested cotton.

Credit for the spinning jenny, the hand-powered multiple spinning machine invented in 1764, goes to a British carpenter and weaver named James Hargreaves. His invention was the first machine to improve upon the spinning wheel. At the time, cotton producers had a difficult time meeting the demand for textiles, as each spinner produced only one spool of thread at a time. Hargreaves found a way to ramp up the supply of thread.

The people who took the raw materials (such as wool, flax, and cotton) and turned them into thread were spinners who worked at home with a spinning wheel. From the raw material they created a roving after cleaning and carding it. The roving was put over a spinning wheel to be twisted tighter into thread, which collected on the device's spindle.

The original spinning jenny had eight spindles side by side, making thread from eight rovings’ across from them. All eight were controlled by one wheel and a belt, allowing for much more thread to be created at one time by one person. Later models of the spinning jenny had up to 120 spindles.

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An invention is a new method, material or machine that applies theoretical principles to a practical use. That does not mean that the inventor necessarily understands why his invention works! Inventions may be the result of hard work, or luck, or both. Very often, it is the name of the person who popularized the new idea that we remember, not the person who first thought of it.

An invention is a unique or novel device, method, composition or process. The invention process is a process within an overall engineering and product development process. It may be an improvement upon a machine or product or a new process for creating an object or a result. An invention that achieves a completely unique function or result may be a radical breakthrough. Such works are novel and not obvious to others skilled in the same field. An inventor may be taking a big step toward success or failure.

Some inventions can be patented. A patent legally protects the intellectual property rights of the inventor and legally recognizes that a claimed invention is actually an invention. The rules and requirements for patenting an invention vary by country and the process of obtaining a patent is often expensive.

Another meaning of invention is cultural invention, which is an innovative set of useful social behaviours adopted by people and passed on to others. The Institute for Social Inventions collected many such ideas in magazines and books. Invention is also an important component of artistic and design creativity. Inventions often extend the boundaries of human knowledge, experience or capability.

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In the eighteenth century, wealthy and influential men often interested themselves in more than one branch of learning. The American Benjamin Franklin was a statesman, printer, author and scientist. He left school at twelve, being the fifteenth child of seventeen, but soon made up for his lack of formal education. As well as his political work, he conducted many experiments concerning electricity. In 1752, he flew a kite in a thunder-storm, attaching a metal key to the damp string. An electrical charge ran down the string and Franklin was able to feel it jump to his finger when he approached the key. From this he concluded that lightning was an electrical spark and in 1753 launched his invention of the lightning conductor.

By 1750, in addition to wanting to prove that lightning was electricity, Franklin began to think about protecting people, buildings, and other structures from lightning. This grew into his idea for the lightning rod. Franklin described an iron rod about 8 or 10 feet long that was sharpened to a point at the end. He wrote, "The electrical fire would, I think, be drawn out of a cloud silently, before it could come near enough to strike..." Two years later, Franklin decided to try his own lightning experiment. Surprisingly, he never wrote letters about the legendary kite experiment; someone else wrote the only account 15 years after it took place.

In June of 1752, Franklin was in Philadelphia, waiting for the steeple on top of Christ Church to be completed for his experiment (the steeple would act as the "lightning rod"). He grew impatient, and decided that a kite would be able to get close to the storm clouds just as well. Ben needed to figure out what he would use to attract an electrical charge; he decided on a metal key, and attached it to the kite. Then he tied the kite string to an insulating silk ribbon for the knuckles of his hand. Even though this was a very dangerous experiment, some people believe that Ben wasn't injured because he didn't conduct his test during the worst part of the storm. At the first sign of the key receiving an electrical charge from the air, Franklin knew that lightning was a form of electricity. His 21-year-old son William was the only witness to the event.

Two years before the kite and key experiment, Ben had observed that a sharp iron needle would conduct electricity away from a charged metal sphere. He first theorized that lightning might be preventable by using an elevated iron rod connected to earth to empty static from a cloud. Franklin articulated these thoughts as he pondered the usefulness of a lightning rod.

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