Refrigeration Refrigeration is the process of removing heat from substances and keeping things cold. Though a relatively modern technique, the ancients knew ways of extracting heat from water and making it cool. They knew that if chemicals like ammonium nitrate and saltpeter were added to water, it would make it cool by lowering the temperature. Besides this the earliest method of refrigeration was by using ice or snow. Today the process...

Furniture   The first known furniture is said to have existed in the Egyptian civilisation about 4000 years ago, though it might have existed in some crude form prior to that. The Egyptians arc said to have used chairs, tables, stools, chests, beds etc. The Assyrians and Babylonians are also said to have had elaborate furniture including high backed chairs and foot stools. In comparison the Greek used much simpler furniture...

Sewing Machine The first sewing machine was patented by a man called Thomas Saint, an Englishman, in 1790. The machine was capable of stitching leather like a modern day machine. However this machine was not produced or marketed. In 1830 a Frenchman called Barthelemy Thimmonier was successful in making a sewing machine which resembled the one we use today. When the manufacturing of this machine began, a large number of tailoring...

Microscope The microscope derives it’s name from the two Greek words `Mikros’ meaning small and `Skopos’ meaning watcher. This aptly defines the purpose of a microscope i.e. to observe small things. The microscope was invented sometime between 1585 and 1610 and though the credit of it’s invention, is given to Galileo, it is also said that a man called Leeuwenhoek may have invented it. The microscope consists of a series of...

Thermometer   We often ask ourselves or someone, how hot or how cold it is. The answer to this simple question would not have been possible without the thermometer. In 1592 Galileo made a device which could measure temperature, it was a crude version of the modern thermometer and was called an ‘air thermoscope’. This device had a glass tube open at one end and a glass bulb at the other....

Compass A magnetic needle balanced on a pivot is the simplest form of a magnetic compass. Since this needle is free to swing in any direction, it would on it’s own move and point to the Earth’s magnetic pole in the north. This is immensely helpful in finding one’s direction since all land and water areas are charted on this basis. The Chinese were among the first people to use the...

Aqualung Inability to breathe under water and increasing water pressure at greater depths were two major deterrents which prevented man from being able to explore the underwater world. In the earlier days cumbersome deep sea suits were used, these were connected to the ships overhead through hoses and air constantly had to be pumped in by seamen. It was only in the year 1943 that a Frenchman called Jacques Cousteau working...

X-Rays In 1895 a scientist called Wilhelm Roentgen was experimenting with cathode rays, electricity discharged under high voltage through a series of tubes, in partial vacuum. He noticed that some crystals lying nearby were glowing. Wilhelm knew that cathode rays could not penetrate glass, thus it was quite possible that some other type of rays also existed. Since these rays were invisible and unknown, he decided to call them `X-Rays’. These...