ANTON VAN LEEVWEEN HOEK
( 1632 - 1772 )
Microscope is an instrument through which we can see the small things which are otherwise cannot be seen with the naked eye. This instrument plays a important role today in science and industry. Simple Microscope was invented by Leevwen Hoek.
Earlier to him, Compound microscope was invented by Galileo. It was little difficult to see through it because magnification was taking place in two stages.
Leevwen Hoek was born on 24 October 1632. The family was living on basket and wine making. After his father’s death Leeven Hoek went to Amsterdam and worked as a clerk in a shop. He returned to his native Delf in Holland and started doing business.
Later he was nominated chamberlain. Leevwen Hoek showed interest in making Glass lenses. He made Lenses of lesser focal length. Few lenses he made were so small like the ball head of pins. He made about 400 lenses. Their microscopic power was from 50 to 300. He examined objects like hair, thread, head of insects etc., Through these lenses while Galileo had used his telescope to see stars and planets. People called Leevwen Hoek, a mad person.
It was a rainy day; he observed very small worms in water through microscope. They were invisible to naked eye. He stored rain water in a mug. While he examined the water he found microbes in it.
They were named animalcules. They spread though air. When he examined few model objects from the mouth and interstines. He could see microbes that caused diseases.
The Royal society honoured Leevwon Hoek in 1680 and he was given membership. The science institute of Paris also honored him. The Queen of Britain, the emperor of Russia, Peter the Great came to see him.
The microscope devised by Leevwen Hoek was very simple having only one lens and it was a good one. The compound microscope had group of two lenses.
Today we have electron microscopes to see virus and very minute particles. These microscopes magnifies them to 100,000 times.
Leevwen Hoek was the first to see the whole circulation of the blood with his own microscope. He was also the first to see the microscopic forms of life such as protozoa and bacteria. He also showed that Weevils, fleas and other tiny creatures come from eggs and are not spontaneously generated.
Leevwen Hoek was a healthy person to live till he was 91. He died in 1772. He was successful because of his remarkable patience.
Google Search Bar
Friday, February 6, 2009
ANTON VAN LEEVWEEN HOEK
ANDREAS VESALIUS
ANDREAS VESALIUS
( 1514 - 1564)
Dr. Vesalius was a Flemish anatomist and physician. He was born into a family long associated with the medical care. He obtained his medical degree from the University of Padua. Then he worked there and teached surgery and anatomy. In 1559 he moved to Spain on an invitation to the Spanish court. He became physician at the court of Philip II. He had left Padua disgusted. He was condemned and people including his professor Jocobus Sylvius called him a madman who is poisoning Europe.
Vesalius’s surgical skills were extraordinary. He dissected. He dissected every sort of animal to improve his skill. He studied the anatomical structure of them. Once he wrote; “I could not even lay my hand upon a dried skull, much less take the chance of making a dissection. He overlooked every dissection he performed. He studied the bones perfectly.
After his enemy Sylirus died, Vesalius was invited back to Padua to take the chair of anatomy. But Vesalius decided to make a pilgrimage to Jerusalem and then go to Padua. On the return journey, in 1564, he was ship wrecked during violent storm, and died on a small island off the Greek coast. He was buried there only.
‘De human corporis fabrica’ is vesalins great work got published in 1543.
ALEXANDER GRAHAM BELL
ALEXANDER GRAHAM BELL
(1847 – 1922 )
Today we see school going children having a mobile phone in their pockets. Using a telephone we can talk to our friends and relatives stationed thousands of miles away from us. Telephone was invented by Graham Bell in 1876. “Watson, Watson, come here, I need you” were the first words on telephone.
Graham Bell was born on March 3, 1847 in Scotland. He was brought up in Boston, Massachussets. Bell opened a school for dumb and deaf in Boston in 1862. Thomas Watson, a knowledgeable person in the field of telegraphy became his friend, with his help Bell developed the telephone. He was playing instruments earlier. They were used for the benefit of the deaf.
The first permanent telephone line was laid in 1877 after Bell palented telephone in 1876. by 1878 telephone exchanges were set up in USA. Telephone system advanced in course of time and 1915 nearly 3400 miles long Telephone line was laid under the sea. Bell was invited to inaugurate the system. Bell told the authorities at the time of inauguration that Watson should be on the other end of the time. The authorities agreed.
Bell said: “Watson, come here I need you.”
Watson replied in a laughing mood “Sir, at this time I cannot come to you. I am so far off from you that it will take me one week to reach you.”
When Bell died in 1922, all telephones in America remained silent for one minute. Thomas Alva Edison made many improvements in Telephony.
ALEXANDER FLEMING
ALEXANDER FLEMING ( 1881 – 1955 )
Penicillin, an antibiotic saved thousands of lives in second world war. Actually it was accidentally discovered by Alexander Fleming in 1928. It can be injected into the human blood for treating diseases live diphtheria, Pnuemonia and severe wounds.
Fleming was a bacteriologist from Scotland. He took his degree in 1906 at St. Mary’s Medical School, London. He joined Army Medical corps and did research. After the first world war he returned to London to work in Medical school. One day he observed some strange flecks of fungus that were grown up in an uncovered pantery dish which he was using for antibacterial experiments. To his surprise he found that wherever the fungus had grown, the bacteria had died. Fleming felt that it was caused by a spore which had flown in through a window and settled on the dish. That was a rare fungus in the mould family. He took the fluid from it and tried it on bacteria. Ultimately he concluded that the fungus had a deadly effect on the disease which cause microbes. The fluid which acted as a repellent to the growth of bacteria was obtained from the penicillium fungus, and was named penicillin. For this wonderful discovery, the Nobel Prize was awarded jointly to Fleming, Florey and chain in the field of medicine in 1945. American drug manufacturers gave Fleming support to isolate Penicillin. In course of time technique of extracting Penicillin in large quantities was evolved.
Fleming died on March 11, 1955 in London
BENJAMIN FRANKLIN
Franklin was born in Boston, USA on Jan 17, 1706. He was the son of a soap and candle maker. Franklin was the fifteenth child in the family. He could not study as he had to pay school ten. He worked in his father’s factory though he was not happy. He desired to become a sailor. His father allowed him to learn printing work from his eldest son James. James was publishing a weekly “The new England news paper”. Benjamin learnt composing and printing at the age 12, He used to read books. He was buying books with the money he saved. He intended to write articles to the news paper which James didn’t like. So he wrote in the name Mrs. Dogwood. James came to know it later and he was anguish at him Benjamin left for Philadelphia where he developed printing and people admired him. He was responsible for the establishment of American philosophical society. The society was helpful later in proclaiming the American independence. Franklin started a mobile library at 25. He opened a study centre at Pensylvania which became Pensylvania university later. Philadelphia was turned into an important city. This was due to Franklin’s efforts. He went to England in 1724. where he worked as master printer.
Franklin found static electricity. In 1752 he conducted an experiment in connection whth electrically charged clouds. While he flew a kite, a key was tied to the in of the metal string that was connected with the kite. The other end of the key was tied to a silk ribbon which franklin held. A bolt of light struck the kite wire and traveled down to the key causing a spark. Franklin proved that lightning is electricity. This showed that large electrically charged clouds can be frought to the earth. Franklin invented a device for the protection of tall buildings from lightning. The device was called the lightning. The device was called the lightning conductor.
Franklin invented pensylvania fire place later called the Franklin stove.
Franklin published his book ‘Experiments and observations on electricity that includes basic principles of electricity. The book was translated into German, French and Italian.
Franklin made significant contributions in the independence of the USA. He signed the declaration of independence on July 4, 1766. He also helped to draw up the constitution of the USA. He refused to patent any of his inventions. He was elected the member of the Royal society, London. He died on April 17, 1790.
SIR ISSAC NEWTON
Newton did his graduation from Trinity college, Cambridge in 1665. His professor was Issac Barrow, a gaint in Mathematics. He recognized the talent in Newton. Newton occupied his chair at the age of 27. in 1672 he was elected a fellow of the Royal Society. Newton published his epic work “Principia Mathematiea” in 1687.
Newton showed that the Sunlight is composed of seven colour VIBGYOR or violet, indigo, Blue, Green, Yellow, Orange and Red. These colours can be separated with the help of a prism and the mixture of these colours produces white light for which Newton made a disc.
Newton became famous by his three laws of motion. They are (1) Everybody contiues in a state of rest or uniform motion in a straight line unless acted upon by an external impressed force (2) The rate of change of momentum is proportional to the impressed force and takes place in the direction of force and (3) Action and reaction are equal and opposite. These laws were first stated by Newton in his prinipia (1687). Newton also invented calculus, a mathematical method. He wrote a book ‘optiks’ describing his studies of light.
It was in the year 1655. Newton was in his native woods Thorpe for holidays. One day he lying on the ground under an apple tree. Suddenly an apple fell to the ground. He wondered at this scene. Why the apple fell towards the ground? Why all the bodies fell toward the earth? Newton thought over the matter. He decided that it is earth’s pull. There is some force that attracts all things towards the earth. He concluded that all bodies attract each other by the same force. On the basis of the falling apple he gave his famous law of Universal gravitation which states that everybody in this universe attracts every other body with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
In 1689 Newton was the member of Parliament. He had represented the university. He was made the President of the Royal Society in 1703 and continued till his death. He was knighted by Queen Anne in 1705. Even at his ripe age of 85 he presided over a meeting of the Royal Society. Newton was a simple man. His scientific achievements are unique. He died on 20 march 1727 at London.
There are few stories about him.
Newton had a pet dog named diamond. One day its movement caused a burning candle to fall on manuscripts. They were burnt into ashes. Newton had prepared them for the past twenty years out of his research. Newton entered his room and found diamond sitting calm. He exclaimed; “Oh, diamond, you do not know what mischief you have done to me!”
Newton was fond of a cat. He had cut a hole in one of the walls of his house to enable the cat to enter the house. One day he saw two kittens. Newton, absent minded cut a little hole for the kittens! Was it necessary?.
ARCHIMEDES
ARCHIMEDES (287 - 212 B.C.)
Archimedes who was born in Syracuse was a great scientist, mathematician and inventor. He is most well known for the utterance ‘Eureka! Eureka’ which meant I have found it! I have found it!” He shouted so because he had discovered the king Hieron’s crown a fake. He found that the specific gravity of the material of the golden crown didn’t tally with that of pure gold. Actually he was lying in a bath tub. He observed that a body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid. This is better known as Archimedes principle. The ratio of the weight of a substance to the weight of water it displaced when immersed in it is hence a constant and is called the specific gravity of the material. Archimedes detected the impurity in the golden crown without breaking. He just filled a vessel with water and dipped the crown in it. He measured the water displaced on account of it. Again he filled the vessel with water and dipped equal mass of pure gold in it. He measured the water displaced this time. The amount of water displaced in the two cases was different. By this he could estimate the impurity in the golden crown made by the Goldsmith which was doubted by the king who had asked Archimedes to test the same without damaging it.
Once Archimedes said to the king: ”Give me a rod of proper length and suitable place to hook one end of it, I shall lift the earth” with the help of levers and pulleys he lifted a loaded ship on to the bank.
Archimedes was a mathematician too. He wrote books like measurement of the circle; on the Sphere and cylinder; method and book of Lemmas. He calculated the value of Pi. He invented few simple machines and war machines.
After the war in 212 B.C. Syracuse came under the Romans. Archimedes was unhappy. One day he was making some geometrical figure, on the ground. An armed soldier threatened him while Archimedes said: “please do not disturb. Let me finish my circle.” But the soldier killed him.
The law of floating explained by Archimedes is Archimedes’ principle. It reasons that a body immersed in water or any liquid will displace a volume of fluid equal in weight to the weight of the immersed body.
GEORG SIMON OHM
Voltage V
I = current = _________ = ___
Resistance R
Georg Simon Ohm was born on 16 March, 1787. His father was a Blacksmith. Ohm became a teacher at the age of 18. He obtained doctorate degree in mathematics in 1811. He wished to join army to fight against Napolean. But his father adviced him to continue teaching profession. He was the professor at the age 30 in Cologue. Ohm published his research paper on electricity in 1827. He also published a book titled mathematical measurements of electric currents. But he was ignored. The people who read his book criticized telling that Ohm’s contribution to science or mathematics is nothing. There were arguments. Ohm resigned his post. He had to live on private tuitions there after. It was only after six years he could enter university again. He was not recognized in Germany. Britain welcomed his theory. The Royal society of London honoured him giving kople medal.
Ohm died in 1854 in Munich. In 1881, the international conference of electrical engineers was held in Paris and it was decided there to call unit of electrical reistance in honour of the scientist as OHM. But it was only after his death. The relation V = IR has brought Italy, France and Germany together.
ROBERT BOYLE
He stated a law related to gaseous pressure. Boyle’s law states that it constant temperature the volume of a given mass of gas is inversely proportional to the pressure that PV = Constant.
Boyle was a kind man and generous. He helped Issac Newton to publish his principia.
Boyle proved that elements cannot be divided. He died on 30 December 1691.
Charles law states that at constant pressure all gases expand by 1/273 of their volume at 0 C; that is the volume of a given mass of gas a constant pressure is directly proportional to the absolute temperature.
Boyle’s law and Charle’s law are called gas laws. These are not perfectly obeyed by ordinary gases being strictly true only for the ideal gases. Amedeo ayogadro law is also a gas law which states that equal volumes of different gases contain the same number of particles if they all have the same pressure and temperature.
ANDRE MARIE AMPERE
Ampere was born on 2 January, 1775 in France. His father was a Jute merchant and a well read man. He introduced Latin and Greek to his son. Ampere when he was child he was solving Arithmetic problems using small stone pebbles. At 11 he had a thorough knowledge in mathematics and calculus.
Those were the days of French revolution. His father was sentenced to death. Ampere was mentally shocked. He had lost his paternal property. He had to earn his livelihood by private tuitions. He married Julie. She gave birth to his son. Ampere got an appointment as teacher in a High school. He worked there for two years and then joined an engineering college in Paris.
In 1819 Johanne C. Oersted of Denmark performed an experiment in which he observed a magnetic needle moving near a wire carrying current. Ampere conducted an experiment to find out the effect of electricity on a magnetic needle. His discoveries helped electrodynamics. It was confirmed that magnets can be developed with the help of electricity. When electricity flows through a coil it gets magnetized and the current starts from its origination and returns through a circuit. Ampere published his book on magnetism and electricity in 1823. He said that molecular electricity causes magnetism. Later it was made known that the flow of electrons constitute current.
ALBERT EINSTEIN
ALBERT EINSTEIN (1879 - 1955)
Einstein was born at Ulm in Germany. He learnt piano from his mother. Right from his childhood he was interested in science. He was sharp in mathematics but a mediocre in other subjects. He completed his education in 1900 and became citizen of Switzerland where he had tried for admission in the Zurich University. He joined the Swiss Patent office as a clerk. He married science student Mileva Marec. In 1905 he got his doctorate degree from Zurich university. By that he had published five research papers which made him a famous scientist as he showed that when light falls on metals like tungsten etc., they emit electrons. These electrons he called photo electrons and the effect “ Photoelectric effect”. He was awarded the 1921 Nobel Prize for his discovery of the law of Photo electric effect.
His major contribution was the special theory of relativity. He showed that the physical quantities like mass, length and time are not constant, but vary with the velocity of the body. He established the equivalence of matter and energy. The interconnection of mass and energy was embedied in the formula E=mc2 where E is energy, m is the mass and c, a constant equal to the velocity of light. The atomic bomb was the result of this equation. He also explained in one of his papers the way the force of gravity works.
In 1933, in Germany the dictatorship of Hitler was found intolerable. Einstein opposed it. The condition of Jews were miserable. Einstein went to America on an invitation to deliver a lecture. He didn’t come back to Germany as he was likely to be punished. He held a high post in Princeton university till 1945. There he worked on the development of Atom bomb. When he found the harmful and disastrous effect of the bomb on the two cities of Japan he became very sad and decided to advocate only the peaceful users of atomic energy. Einstein died on April 18, 1955. An element Einsteinium has been named after him. He is sometimes called the father of modern physics.
FRANCIS BACON
FRANCIS BACON (1561 - 1626)Bacon was born in 1561. His father Nicolas Bacon was a security officer to Queen Elizabeth. His mother was Lady Anne Cooke. She knew several languages and helped Bacon to get educated. He went to Cambridge to study in Trinity College. He studied there for three years. But he did not like the teaching methods and left college. He felt that he has taken birth to serve human. He was a thinker. He was appointed English ambassador in France at the age of 16. his father died in 1579. Bacon didn’t get any property from his father. He returned to England and became unemployed. He fell in poverty. He worked hard to get success.
Francis bacon was elected to parliament in 1583. He was popular. In 1606 he was Solicitor general and Advocate general in 1613. He became the Lord Chancellor in 1618.
Francis Bacon was of he opinion that a scientist should rule a state. He felt that a Governor of a state should do jobs like seeing development of industries, inventing new gases and use them for treating diseases, improve surgery skills by doing experiments on animals etc.,
Bacon died on April 5, 1626 at the age 65.
