Category Science

What are quarks?

            All matter is made up of small particles called atoms. These atoms are very tiny particles and cannot be seen with the naked eye. Atoms are made up of still smaller particles called electrons, protons and neutrons, which are known as subatomic or elementary particles. Physicists have discovered hundreds of other elementary particles such as mesons, muons, neutrino end positrons. Can you imagine a particle even smaller than these elementary particles?

            A few years ago, scientists discovered that elementary particles are made up of extremely small particles called quarks. So far quarks are only hypothetical particles and have not been observed in experiments. With the exception of protons, electrons, muons and neutrino, all elementary particles are made up of different quarks. This idea was suggested in 1964, by two American physicists, Murray Gell Mann and George Zweig. 

           There are probably four different kinds of quarks, carrying a fractional charge. Each has an anti-particle called anti-quark. Until 1974, only three types of quarks were known; two of very nearly equal mass, of which the proton, neutron and pi-mesons are composed, and a third, bigger quark which is a constituent of K-mesons and hyperons. These quarks are called the up quark (u), the down quark (d) and the strange quark (s). In 1974, one more quark, named charm quark (c) was also predicted. The existence of two other types, top quark and bottom quark, is also predicted.

             The charges of the four quarks u, d, s and c are +2/3, -1/3, -1/3, and +2/3 that of the electron charge.

             Anti-quarks have opposite charges. All quarks and anti-quarks have equal spin which is 1/2.

             These quarks combine to form different elementary particles. For example, protons are composed of three quarks (uud) and neutrons also of three quarks (udd). Each meson can be conceived as the union of a quark and an anti-quark.

 

What is a Robot?

          A robot is an automatic machine which can work like a human being. It can replace man in various branches of scientific and industrial tasks because it does not suffer from human limitations. It may or may not resemble a human being but definitely can work like a human being. The robots which resemble humans are called androids.

          The word ‘robot’ was first used in the play ‘Rossum’s Universal Robots’ by the Czechoslovak dramatist, Karel Capek, who had derived it from a Czech, word ‘Robota’ which means a forced or bonded labourer.

          The industrial revolution and automations stimulated the invention of robotic devices to perform certain human tasks. A human worker, however superb a craftsman he may be has certain limitations. He cannot work continuously in a hostile environment. He cannot work for long periods because he gets tired. He may be in short supply and may be expensive to hire. Modern industrial robotic devices aim to substitute a machine for man in hostile environments, cut costs by replacing expensive hand labour with cheap dependable machines, and provide versatile, all purpose robots or mechanical devices at predictable costs. Robot is such a machine which does not get tired, does not go on strike and does not demand increase in salary. 

          Robots can perform a variety of jobs such as welding and painting a car, house cleaning, cutting the grass of a lawn, working in nuclear plants or travelling to space. They can also play chess, work as a watchman, cut the wool of a sheep and pluck fruits from trees.

          Robots of higher level are capable of adapting to changes in environment. They are also capable of making decisions with the help of computers. A more complex robotive device in modern transportation is the automatic aircraft pilot which can control routine flights. An android robot named Shaky Robot was developed at Stanford Research Institute in California to do a variety of research jobs.

          Japan has the largest number of robots in the world. The United States of America, Britain, Germany, Sweden, Italy, Poland, France, India, etc are also using robotic devices for different purposes. All robotic devices are controlled by computers.

 

Roddam Narasimha

Roddam Narasimha (born 20 July 1933) is an Indian aerospace scientist and fluid dynamicist. He was a Professor of Aerospace Engineering at the Indian Institute of Science (IISc), Director of National Aerospace Laboratories (NAL) and the Chairman of Engineering Mechanics Unit at Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore, India. He is now an Honorary Professor at JNCASR and concurrently holds the Pratt & Whitney Chair in Science and Engineering at the University of Hyderabad. Narasimha has been awarded the Padma Vibushan, India’s second highest civilian award, in 2013.

Education and career

He obtained his BE from Mysore University , from University Visvesvaraya College of Engineering in 1953 and his ME from Indian Institute of Science, Bangalore in 1955. He worked with Satish Dhawan during his time at IISc. He then worked with Hans Liepmann at the California Institute of Technology (Caltech), United States to obtain his PhD degree in 1961.

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Where do penguins live?

               Penguins are a peculiar category of sea birds which can stand up straight and flat-footed like us. Do you know where these birds are found?

               Penguins are found in Southern hemisphere. They live along the Antarctic continent and islands as well as on the cool Southern hemisphere coast of Africa, Australia, New Zealand and South America.

              The wings of penguins have evolved into flippers. As a result, they can not fly but they are excellent swimmers. They walk in a strange manner. In the earlier phases of evolution they could fly like other birds. But over a period of time, their wings became very short. The reason is that penguins lived in the remote areas of Antarctica, where they had practically no enemies to attack them. So they lived safely in land and water without ever using their wings and in course of time their wings became very small. 

            

             

               Penguins live in flocks. A single rookery may contain more than a million penguins. They feed on fish, squids and crustaceans.

               Penguins withstand extremely cold conditions on account of a very dense plumage all over their bodies. These feathers are waterproof and have tiny air spaces that help them keep warm. Underneath this thick coat of feathers, there is an insulating layer of blubber. This helps to keep the body warm and store food and water. They also have a thick coat of fat to protect them from the cold.

               Female penguins lay one or two eggs, which are brooded by both parents. They do not take food during incubation. Young penguins are fed by regurgitation. There are 17 species of penguins. The species differ mainly in head pattern and in size. Their sizes vary from 40 cm (fairy penguin) to almost 120 cm (Emperor penguin). Both sexes are alike in size. Only two, the Emperor and Adelie penguins breed on the Antarctic coast. King, Macaroni, Chinstrap and Gentoo penguins breed on Sub-Antarctic islands. The remaining 11 species breed farther North.

How can dogs be dangerous to us?

          It has often been said that a dog is a man’s best friend. In fact, the dog was the first animal to be domesticated by man. But dogs can also be a source of danger under certain conditions.

         A dog can harm people by biting or transmitting several bacterial, viral, parasitic, fungal and rickettsial diseases.

          Bacterial diseases transmitted by dogs are mainly tuberculosis brucellosis, splenic fever, scarlet fever, diphtheria etc. Dogs carry Salmonella enteriditis and S. typhinurium pathogens which cause gastroenteritis and typhoid in man.

Dogs along with other animals can transmit fungal diseases such as ringworm.

          Rabies is the most dangerous viral disease caused by a dog-bite. Rabies virus is found in the saliva of rabid dogs. Sometimes even pet dogs can be the cause of this disease. Therefore it is essential that they should be vaccinated against rabies every three years.

          Dogs occasionally get measles and mumps and can cause this infection to spread to human beings.

        

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Which are the large-sized flying birds?

               The largest of all living birds is the African Ostrich which cannot fly at all. It measures upto 2.4 m in height and may weigh more than 133 kg. On account of its weight, it finds it impossible to lift its body in the air.

               The two groups of flying birds that have the largest wingspread are the albatross and the condors. Both of them weigh about 13.5 kg. 

 

 

          The wandering albatross leads among the largest flying birds with a wing-spread of 3.3 to 3.6 m. The albatross has a long, heavy beak and long, narrow wings. It is mainly found in places south of the equator. It is a sea bird. It needs some wind and a run before taking off. So it either runs along the ground or paddles with its webbed feet across the water for a long time before being able to fly.

 

 

               Next comes the condor which has a wingspread of 3 to 3.3 m. It is a carnivorous bird. There are two species of condors in the world. The Andean condor lives in the Andes Mountains in South America. The other one is the Californian condor which is found in the mountains of Southern California. They feed on carcasses of animals. While searching for food, the condor uses its broad wings to glide high in the air.

 

 

         

              The third bird in this line is the king vulture which is found in South America, Mexico and Central America. It has a wingspread of 2.7 to 3 m. The white pelican comes after the king vulture. It has a wingspread of 2.4 to 2.7 m. It is found in Canada. One of its distinguishing features is a bag-like pouch under its bill. Functioning like the radiator in a car, it helps the pelican to keep cool.

           

   The great bustard, a large goose-like bird related to the cranes comes next. It is found in parts of Europe, Asia and Africa and has a wingspread of 2.4 to 3.7 m. The American bald eagle is the next largest flying bird having a wingspread of 2.1 to 2.4 m. Then comes the sandhill crane, with a wingspread of 1.8 to 2.1 m.