Evolution of Transport
Before the invention of the wheel, the only means of transportation was walking. For transporting goods, people used animals like donkeys, horses, mules, elephants, oxen, sled dogs and bison. Boats were used as a means of transportation on water. The earliest boats were simple logs of wood with a hollow cavity.
The oldest wheel was discovered in Mesopotamia, which was believed to be over 5,500 years old. Carts fixed with wheels were invented around 3,500 BC, according to some historians. After the invention of the wheel, man started using animals to pull vehicles that moved on wheels, and thus, bullock carts and chariots came into existence. The invention of the wheel revolutionised transport and wheel design was improved over thousands of years.
Till the beginning of the 19th century, people depended on animals for transportation of goods. Animals were used to pull vehicles that moved on wheels. Popular vehicles, like the bicycle, were invented in the late 18th century. The first bicycles did not have any brakes. It was up to the rider to control the speed or stop the bicycle with his feet. Later on, motors were fitted to bicycles, and thus, mopeds came into existence. Further research and development led to the invention of the motor car.
The steam engine and the rail road were invented in the 19th century. The invention of the steam engine introduced a new source of power for transportation. Rail tracks were made for steam-engine-driven carriages and wagons to transport goods. Apart from these, motorised boats and ships were used as a means of water transport. Roads, rail roads and water remained the major means of transport for a very long time.
The Wright brothers invented the airplane and gave the world another means of transport – airways. Electric trains, monorails, supersonic aeroplanes and spacecraft are some of the contributions of the 20th century to transportaion. One of the most exciting developments in travel is the flying train. It is referred to as the flying train because it does not touch the rails as it moves. Huge magnets
keep the train suspended in air. In his effort to explore the universe, man has even invented the spaceship to travel in space and stepped into the space.
There are various means of transport, such as road, rail, water and airways. The mode of transport can be chosen depending upon the distance to be travelled and how fast one wants to get to the destination.
Evolution of Standard Units of Measurement
Before the metrics for measurement were developed, people used several different means to calculate distance and length
. For instance, a carpenter would measure the length of wood using his palm, fingers or arm. Similarly, a cloth merchant would measure the length of cloth against his outstretched arm. Foot length or palm length were commonly used as non-standard units of measurement. The base measurement for the pyramids is the cubit, which was formulated by the Egyptians. A cubit was measured on the arm, from the point where the elbow bends, to the tip of the middle finger. One cubit is approximately equal to 18 inches. The inch was invented by the Romans.
Scientists all over the world felt the need for uniformity in the standards for the measurement of lengths and distances. In order to avoid confusion in measurements, the French created in 1970 the metric system, which is a standard for measurement. A further development to ensure uniformity in the measurement of lengths and distances, and other quantities, was a standard of measurement called the International System of Units or SI units
. The SI unit of length is the metre (m). The multiples and submultiples of metre are given below.
1 decametre (dam) = 10 m
1 hectometre (hm) = 100 m
1 kilometre (km) = 1000 m
1 m = 10 decimetre (dm)
1 m =100 centimetre (cm)
1 m = 1000 millimetre (mm)
Large distances are measured in kilometres. The length and type of an object determines the kind of measuring tool that can be used.