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Long before watches were invented people kept track of time with the help of the sun. Later, Sundials, water clocks, sand glasses or hour glasses, and lamps or candle clocks were created to measure time. The oldest sundial, dating back to 1500 BC was made in Egypt Let's rewind a little to look at how watches have evolved over time

Early watches

In the 1500s, Peter Henlein, a locksmith from Nuremberg, Germany, made a portable, round clock with wheels. It was powered by a metal string. It was called the Nuremberg Egg' because of its shape.

People in France, England, and Switzerland also started to make watches but with only the hour hand. All required to be wound twice a day. Some had dials with the numbers 1 to 12 marked in the outer circle, and 13 to 24 in the inner circle. As watches came to be regarded as jewellery pieces, watchmakers began decorating watch cases with precious stones. They were worn around the neck, mainly by women.

Watches with spring mechanism

 The spiral balance spring mechanism was first used in watches in 1675. The credit for introducing this mechanism, which greatly improved the accuracy of watches, goes to Dutch scientist Christiaan Huygens and English physicist Robert Hooke Minute hands were added to watches a few years later.

During this time, King Charles II of England set the fashion of wearing long waistcoats Men stopped wearing their watches around their necks and started keeping them in the pockets of their long waistcoats.

In 1770, Abraham-Louis Perrelet invented a self-winding mechanism for pocket watches. It was designed to wind as the owner walked. Constant improvements were made thereafter, and watches became smaller and more accurate. Balance wheels and hair springs were introduced, and jewels came to be used as bearings.

The first wristwatch

Polish watchmaker Antoni Norbert Patek and French watchmaker Adrien Philippe are credited with inventing the first wristwatch in the late 19th Century. Initially men did not wear it, as they regarded it as a lady's accessory. The mass production of wristwatches took place after World War I, when army officers found it impractical to fumble for their watches in their waist pockets in the midst of battle. Wristwatches were found to be more practical, and by the end of the war. Switzerland boasted of being the world's largest and most organised watch industry. Electronic wristwatches, such as the quartz watch, were invented towards the end of the 20th Century.

Today you get wristwatches that don't just show the time, date, day of the week, month, and year, but also have calculators, digital cameras, and video games. Many are water-resistant and can withstand extreme temperatures. Eco-friendly watches that work on sunlight are also available, and so are gold and platinum watches studded with precious stones.

Picture credit : Google 

Sheldon Glashow, Abdus Salam, and Steven Weinberg were awarded the 1979 Nobel Prize in Physics for their contributions to the unification of the weak and electromagnetic interaction between elementary particles.

The Royal Swedish Academy of Sciences has decided to award the 1979 Nobel Prize in physics to be shared equally between Professor Sheldon L. Glashow, Harvard University, USA, Professor Abdus Salam, International Centre for Theoretical Physics, Italy and Imperial College, Great Britain, and Professor Steven Weinberg, Harvard University, USA, for their contributions to the theory of the unified weak and electromagnetic interaction between elementary particles, including inter alla the prediction of the weak neutral current.

Physics, like other sciences, aspires to find common causes for apparently unrelated natural or experimental observations. A classical example is the force of gravitation introduced by Newton to explain such disparate phenomena as the apple falling to the ground and the moon moving around the earth.

Another example occurred in the 19th century when it was realized, mainly through the work of Oersted in Denmark and Faraday in England, that electricity and magnetism are closely related, and are really different aspects of the electromagnetic force or interaction between charges. The final synthesis was presented in the

1860’s by Maxwell in England. His work predicted the existence of electromagnetic waves and interpreted light as an electromagnetic wave phenomenon.

The discovery of the radioactivity of certain heavy elements towards the end of last century, and the ensuing development of the physics of the atomic nucleus, led to the introduction of two new forces or interactions: the strong and the weak nuclear forces. Unlike gravitation and electromagnetism these forces act only at very short distances, of the order of nuclear diameters or less. While the strong interaction keeps protons and neutrons together in the nucleus, the weak interaction causes the so-called radioactive beta-decay. The typical process is the decay of the neutron: the neutron, with charge zero, is transformed into a positively charged proton, with the emission of a negatively charged electron and a neutral, massless particle, the neutrino.

Although the weak interaction is much weaker than both the strong and the electromagnetic interactions, it is of great importance in many connections. The actual strength of the weak interaction is also of significance. The energy of the sun, all-important for life on earth, is produced when hydrogen fuses or burns into helium in a chain of nuclear reactions occurring in the interior of the sun. The first reaction in this chain, the transformation of hydrogen into heavy hydrogen (deuterium), is caused by the weak force. Without this force solar energy production would not be possible. Again, had the weak force been much stronger, the life span of the sun would have been too short for life to have had time to evolve on any planet. The weak interaction finds practical application in the radioactive elements used in medicine and technology, which are in general beta-radioactive, and in the beta-decay of a carbon isotope into nitrogen, which is the basis for the carbon-14 method for dating of organic archaeological remains.

Credit : The Nobel prize

Picture Credit : Google 

Analysis of a 'super-deep' diamond from Orapa, Botswana, has revealed tiny crystals of a never-before-seen mineral trapped inside.

Davemaoite, named after geophysicist and deep-earth scientist, Ho-kwang (Dave) Mao, is the first example of a high-pressure calcium silicate perovskite (CaSiO3) found on Earth. Its crystalline structure forms only under high pressure and high temperatures in Earth's mantle, the mainly solid layer of Earth between the outer core and the crust.

Normally, Davemaoite's crystal structure would break apart if it was brought up to Earth's surface because of the massive drop in pressure. But because it was trapped inside a rigid diamond, it was preserved on its long journey up to the Orapa mine, which probably took between 100 million to 1.5 billion years.

Most diamonds form 120 to 250 kms underground, but those of the super-deep variety are born in Earth's lower mantle, which begins 660 kms below the surface.

Davemaoite makes up around 5-7% of the material in Earth's lower mantle, and is important because it can host radioactive elements like uranium, thorium and potassium-40 that heat Earth as they decay.

Picture Credit : Google