INVENTION OF WHEELSThe wheel is everywhere on all our cars, trains, planes, machines, wagons, and most factory and farm equipment. What could we move without wheels? But as important as the wheel is as an invention, we don't know who exactly made the first wheel.

The oldest wheel found in archeological excavations was discovered in what was Mesopotamia and is believed to be over fifty-five hundred years old.

Development of a Functional Wheel

The following steps and developments took place to invent a functioning wheel, more or less in this order:

This is Heavy

Humans realized that heavy objects could be moved easier if something round, for example a fallen tree log, was placed under it and the object rolled over it.

The Sledge

Humans also realized a way to move heavy objects, with an invention archeologists call the sledge. Logs or sticks were placed under an object and used to drag the heavy object, like a sled and a wedge put together.

Log Roller

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Humans thought to use the round logs and a sledge together.

Humans used several logs or rollers in a row, dragging the sledge over one roller to the next.

Traditional means

Walking

In ancient times, people often covered long distances on foot. For instance, Adi Sankaracharya traveled all over India. Walking still constitutes an important mode of transport in urban areas. In the city of Mumbai, to further improve the transit conditions for pedestrians, the Mumbai Metropolitan Region Development Authority, has commenced the construction of more than 50 skywalks, as part of the Mumbai Skywalk project.

Palanquin

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A photo of a palanquin at Varanasi. C. 1890s

Palanquins also known as palkis, were one of the luxurious methods used by the rich and noblemen for travelling. This was primarily used in the olden days to carry a deity or idol of a god, and many temples have sculptures of god being carried in a palki. Later on, it was primarily used by European noblemen and ladies from the upper classes of society prior to the advent of the railways in India. Modern use of the palanquin is limited to being an ostentatious method for the bride to enter indian weddings.

NASA Space Shuttle

After a gap of six years, NASA returned to human spaceflight in 1981, with the advent of the Space Shuttle. The Shuttle's first mission, STS-1, took off on April 12, 1981, demonstrating that it could take off vertically and glide to an unpowered airplane-like landing. On STS-6, during April 4-9, 1983, F. Story Musgrave and Donald H. Peterson conducted the first Shuttle EVA, to test new spacesuits and work in the Shuttle's cargo bay. Sally K. Ride became the first American woman to fly in space when STS-7 lifted off on June 18, 1983, another early milestone of the Shuttle program.

On January 28, 1986 a leak in the joints of one of two Solid Rocket Boosters attached to the Challenger orbiter caused the main liquid fuel tank to explode 73 seconds after launch, killing all 7 crew members. The Shuttle program was grounded for over two years, while NASA and its contractors

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worked to redesign the Solid Rocket Boosters and implement management reforms to increase safety. On September 29, 1988, the Shuttle successfully returned to flight. Through mid-1998, NASA has safely launched65 Shuttle missions since the return to flight. These have included a wide variety of scientific and engineering missions. There are four Shuttle orbiters in NASA's fleet: Atlantis, Columbia, Discovery, and Endeavour.

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TRANSPORTATION IN ANCIENT EGYPT

Chariots

    For their daily use even the pharaohs preferred the chariot. Horses were introduced into Egypt by the Hyksos in the 17th century. Although the art of riding was known and occasionally practiced, horses were generally not mounted until half a millennium later, but were harnessed to chariots. Expensive to keep, they never became a popular means of transportation and served only the elite and the military.

Sledges

Wheeled vehicles were never widely used and for heavy loads they were not strong enough anyway. Giant statues and the like were loaded onto wooden sledges and dragged by large numbers of men. Smaller loads were also often transported by sledge. In the tomb of Petosiris (ca.300 BCE) there is a depiction of a mummy being transported to its tomb on a wheeled hearse, which was, even in this late era, unusual. The little naos following the hearse on the other hand was loaded onto a sledge.

To facilitate the movement of sledges on packed, sunbaked soil, small amounts of water were poured on the ground before them, turning the top layer into a slick,

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smooth surface. More rarely the sledges were placed on rollers.

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