Lecture 37

دوره: سخنرانی ها / فصل: سخنرانی ها / فصل 37

Lecture 37

توضیح مختصر

  • زمان مطالعه 0 دقیقه
  • سطح خیلی سخت

دانلود اپلیکیشن «زبانشناس»

این فصل را می‌توانید به بهترین شکل و با امکانات عالی در اپلیکیشن «زبانشناس» بخوانید

دانلود اپلیکیشن «زبانشناس»

فایل صوتی

برای دسترسی به این محتوا بایستی اپلیکیشن زبانشناس را نصب کنید.

متن انگلیسی فصل

Listen to part of a lecture from a social sciences class.

Prof: We don’t know with certainty who invented the bicycle, or where it was invented, or when. Ahem (clears throat). We do know that the modern bicycle had several precursors from different parts of Europe, and that many of its individual components were developed separately at different periods of time. Some historians claim that the famous artist Leonardo da Vinci is the true father of the bicycle. In 1490, da Vinci sketched a remarkable facsimile of a modern bicycle, but his idea was never implemented. Ironically, da Vinci also sketched a modern helicopter hundreds of years before it was officially “invented.” Hmm. Anyway, about three hundred years later, a French inventor built something similar to a bicycle, called a running machine. This contraption was made of wood, and it had two wheels connected by a beam, but no pedals or a, um, steering mechanism. Riders propelled the machine by straddling the beam and pushing with their feet along the ground, like a scooter. You can imagine what steering and stopping were like. In 1817, a German named Karl von Drais improved the running machine by adding a front wheel that could be easily steered. He called his device a Draisienne, but because that word was hard to pronounce, it became popularly known as a “hobby horse,” which was the name of a popular children’s toy at the time. Hobby horses were a popular fad for awhile. However, they were still hard to ped– still hard to propel along the unpaved roads of that day.

Many credit Kirkpatrick Macmillan with the invention of the first modern bicycle in 1839. Macmillan, a Scottish blacksmith, made a rear-wheel driven machine that people said could reach high speeds – high being a relative term, of course. The French, however, said, er, took exception to Macmillan’s claim. To this day, they call Pierre Michaux the “father of the bicycle,” because Michaux and his son, Ernest, added pedals and cranks in the mid-1860s.Their called their innovation a velocipede, which means “fast foot,” and it sparked a bicycle craze in both Europe and the US. Um, just like hobby horses, though, the popularity of velocipedes was short-lived. Turns out velocipedes were heavy, clumsy to mount and steer, and, despite their nickname, slow.

Next, in 1870, a British engineer named James Starley developed a more efficient, all-metal machine. Starley dubbed it a “penny farthing,” and later it was the first machine to be called a bicycle – meaning “two wheels.” Penny farthings had a gi –er, large front wheel and a small back wheel, along with wire spokes and something new: solid rubber tires, courtesy of another Brit – R.W. Thompson – who had patented the first type of rubber inner tube in 1845. These tires provided a smoother ride, because the as the large front wheel could travel, um, farther with one rotation of the pedals. Penny farthings had a serious fault that proved to be their undoing. The front wheel was cartoonishly large, as high as 60 inches off the ground, and the rider’s seat sat directly atop the wheel, so when riders fell, they risked serious injury. It was akin to falling off a horse.

What to do? Well, engineers experimented with a variety of different designs. One of these included adding a third wheel, which was the birth of the modern tricycle. British engineers, including Starley, led the way in this effort. In the mid-1880s, the Starley Rover “safety bicycle” was introduced. This machine looked like a modern bicycle, with equal-size wheels and a rider’s seat positioned between them, and uh- above the pedals. It also had a chain drive, gears, and a new kind of rubber tire that helped absorb shocks from bumpy roads. Although the Rover was much more steady, er, stable than penny farthings, riders still complained of vibration and road shock caused by the smaller wheels. So inventors got to work again. They developed springs in the frame to help absorb road shocks, and as roads became better, the 1890s saw a worldwide bicycle craze. Bikes were now safe, reliable forms of transportation that could be used for both work and leisure.

Keeping the basic shape of the Rover, bicycle design kept improving after the turn of the century. Childrens’ bikes boomed after World War I, and in the 1970s “ten-speed” bikes became popular, with adjustable gears for going up and down hills. Later, “mountain bikes,” with wider tires and up to 30 gears, came into vogue. Today, bicycles are no longer limited to the road. There are mountain bikes, road bikes, motorized bikes, and electric bikes. Who knows what the future holds? Maybe bikes will be able to fly.

مشارکت کنندگان در این صفحه

تا کنون فردی در بازسازی این صفحه مشارکت نداشته است.

🖊 شما نیز می‌توانید برای مشارکت در ترجمه‌ی این صفحه یا اصلاح متن انگلیسی، به این لینک مراجعه بفرمایید.