Saturday, July 3, 2010

SCIENTIFIC LAWS


Archimedes’ Principle: It states that a body, when immersed in a liquid, experiences an upward thrust equal to the weight of the liquid displaced by it.

Avogadro’s Hypothesis: It is a modification of Berzelius’ hypothesis. It states that equal volumes of all gases under similar conditions of temperature and pressure contain equal number of molecules. Avogadro’s law is applicable only to gases.

Boyle’s Law: states that the volume of certain gas is inversely proportional to the pressure at a constant temperature. In other words the product of pressure and volume remains constant provided the temperature is kept constant i.e., P x V = a constant if T remains the same.

Charles’s Law: It states that at constant pressure all gases expand by 1/273 of their volume at 0°C for a rise in temperature of 1°C i.e., the volume of a given mass of gas at constant pressure is directly proportional to the absolute temperature.

Dulong and Petit’s Law: states that the product of atomic weight and specific heat of solid elements is nearly equal to 6.4 i.e., At wt. x sp. heat = 6.4 approx.

Gay-Lussac’s Law of combining volumes: Gases react together in volumes which bear simple whole number ratios to one another and also to the volumes of the products, if gaseous—all the volumes being measured under similar conditions of temperature and pressure.

Graham’s Law of Diffusion: states that the rates of diffusion of gases are inversely proportional to the square roots of their densities under similar conditions of temperature and pressure.

Kepler’s Law: According to this law, a line drawn from the sun to a planet, moving around it, sweeps over a fixed area in a given interval of time.

Law of definite proportions: A chemical compound is always found to be made up of the same elements combined together in the same ratio by weight.

Law of Floatation: for a body to float, the following conditions must be fulfilled: (1) The weight of the body should be equal to the weight of the water displaced. (2) The centre of gravity of the body and that of the liquid displaced should be in the same straight line.

Lenz’s Law: When there is change in the magnetic flux linked with a circuit, the electric current induced in the circuit will have a magnetic field opposing the change producing it.

Newton’s Law of Universal Gravitation: states that “Every portion of matter attracts or tends to approach every other portion of matter in the universe with a force proportional to the masses and inversely as the square of the distance.”

Newton’s First Law of Motion: “A body continues in its state of rest or of uniform motion in a straight line unless compelled by an external force to change that state.”

Newton’s Second Law of Motion: “The rate of change of momentum is proportional to the impressed force and takes place in the direction of the force.”

Newton’s Third Law of Motion: “To every action, there is an equal and opposite reaction.”
Newton’s Law of Cooling: states that the rate of loss of heat of a hot body is directly proportional to the difference of temperature between the body and the surroundings and is independent of the nature of the body.

Ohm’s Law: states that the ratio of the potential difference between the ends of a conductor and the current flowing in the conductor is constant, e.g., for a potential difference of E volts and a current I amperes, the resistance R, in ohms is equal to E/I.

Principle of conservation of energy: It states that, in any system, energy cannot be created or destroyed; the sum of mass and energy remains constant.

Snell’s Law: It states that the ratio of the sine of angle of incidence to the sine of the angle of refraction remains constant for any two given media.

Specific heat of substance: The quantity of heat required to raise the temperature of 1 gram. of a substance through 1°C.

SCIENTIFIC INSTRUMENTS


Altimeter: an apparatus used in aircraft for measuring altitudes.
Ammeter: is used for to measure intensity of sound.
Anemometer: is an instrument for measuring the force and velocity of wind.
Audiometer: an instrument to measure intensity of sound.
Audiophone: is an instrument required for improving imperfect sense of hearing.
Barograph: for continuous recording of atmospheric pressure.
Barometer: is an apparatus used for measuring the atmospheric pressure.
Binoculars: is an instrument used for seeing distant objects, the rays of light are twice reflected by means of right-angled prisms.
Callipers: a compass with legs for measuring the inside or outside diameter of bodies.
Calorimeter: an instrument used for measuring quantities of heat.
Carburettor: is an apparatus for charging air with petrol vapours in an internal combustion engine.
Cardiogram: a medical instrument used for tracing the movements of the heart.
Cardiograph: is a medical instrument for tracing heart movements.
Chronometer: is an instrument kept on board the ships for measuring accurate time.
Cinematograph: It consists of a series of lenses arranged to throw on a screen an enlarged image of photographs. The lens system which forms the image on the screen is termed the focusing lens.
Commutator: split ring which forms the main part of a D.C. Dynamo.
Compass needle: for knowing approximately the North-South direction at a place.
Crescograph: is an instrument for use in recording growth of plants; invented by J.C. Bose.
Dip Circle: It is an instrument used to determine the angle between the direction of the resultant intensity of earth’s field and the horizontal component at a place. This particular angle is know as the dip of that place.
Drinker’s apparatus: to help breathing in infantile paralysis.
Dynamo: The origin of electricity in a Dynamo is the transformation of mechanical energy into electrical energy. It depends on the principle of electro-magnetic induction whereby a current is produced on traversing a magnetic field.
Electroencephalograph (EEG): It is the technique of recording and interpreting the electrical activity of the brain. Records of the electrical activity of the brain, commonly known as “brain waves”, are called electroencephalograms or electroencephalographs. EEG is the common abbreviation for both the technique and the records.
Epidiascope: for projecting films as well as images of opaque articles on a screen.
Eudiometer: It is a glass tube for measuring volume changes in chemical reactions between gases.
Fathometer: is an instrument used for measuring depth of the ocean.
Galvanometer: an instrument for measuring currents of small magnitude.
G.M. Counter (Geiger Muller Counter): This special device is used for detecting the presence of radiation and counting certain atomic particles.
Gramophone: an instrument with which we can reproduce the sound recorded by a suitable recording apparatus. It is fitted with a special type of apparatus known as sound box invented by Berliner.
Gravimeter: is an instrument for recording measurement under water and to determine the presence of oil deposits under water.
Gyroscope: is an instrument used to illustrate dynamics of rotating bodies. It is a type of spinning wheel fixed to the axle.
Hydrometer: is an instrument used for measuring the specific gravity of liquids.
Hydrophone: is an instrument used for recording sound under water.
Hygrometer: is an instrument used for measuring humidity in air.
Kymograph: is an instrument used to record graphically various physiological movements i.e., blood pressure, heart beating, study of lungs etc in living beings.
Lactometer: is an apparatus used for measuring the purity of milk.
Manometer: for determining the pressure of a gas.
Mariner’s Compass: is an apparatus which is used to guide the sailors. The needle always points north-south.
Micrometer: is an instrument used for converting sound i.e., fraction of the lowest division of a given scale.
Microphone: is an instrument used for converting sound waves into electrical vibrations.
Microscope: is an instrument which is used for magnifying minute objects by a lens system.
Microtome: is used for cutting an object into thin parts for microscopic inspection.
Odometer: is an instrument by virtue of which the distance covered by wheeled vehicles is recorded.
Periscope: It is usually used by the crew of a submarine to survey the ships etc, on the surface of the sea while the submarine is under water. It also enables the sailors to observe objects on the other side of an obstacle without exposing themselves.
Phonograph: is an instrument used for reproducing sound.
Photometer: is an apparatus used to compare the illuminating power of two sources of light.
Pipette: It is a glass tube with the aid of which a definite volume of liquid may be transferred.
Potentiometer: is used for comparing the e.m.f.s, of cells, measurements of the thermal e.m.f.s, large potential differences and currents. It is also used for measuring low resistances.
Psychrometer: is an instrument for measurement of the humidity of the atmosphere.
Pyrometer: is an instrument for recording high temperatures from a great distance (i.e., for recording temperature of the sun etc.) by making use of the laws of radiation.
Radar: Radio, Angle, Detection And Range is used to detect the direction and range of an approaching aeroplane by means of radio microwaves.
Rain Gauge: is an apparatus for recording of rainfall at a particular place.
Radiometer: is an instrument for measuring the emission of radiant energy.
Refractometer: is an instrument to measure refractive indices.
Saccharimeter: is an instrument for determining the amount of sugar in a solution. It is used in breweries.
Seismometer or Seismograph: is an instrument used for recording earthquake shocks.
Sextant: is an instrument invented by John Hadley used for measuring the altitude of the sun and of other inaccessible heavenly bodies.
Spectrometer: (1) It is a type of spectroscope suitable for the precise measurements of refractive indices. (2) An instrument for measuring the energy distribution of a particular type of radiation.
Speedometer: is an instrument which indicates speed at which a vehicle is moving.
Spherometer: is an instrument for measuring curvature of surfaces.
Sphygmomanometer: an instrument used for measuring arterial blood-pressure.
Sphygmophone: an instrument, with the help of which a pulse beat makes a sound.
Sphygmoscope: an instrument, by virtue of which, arterial pulsations become visible.
Stereoscope: It is a special type of binocular, through which a double photograph snapped from two different angles by a two-lensed camera is viewed in solid relief.
Stethoscope: is an instrument to hear and analyse movements of heart and lungs.
Stop watch: for recording small intervals of time in the laboratory, in races and other events.
Stroboscope: is an instrument for viewing objects moving rapidly with a periodic motion and to see them as if they were at rest.
Tachometer: is an instrument for determining speeds of aeroplanes and motor boats.
Telephone: a device by virtue of which two persons at two different places can communicate. It consists of two main parts (i) a microphone and (ii) a receiver.
Teleprinter: an instrument which prints automatically messages sent from one place to another, on telegraph lines.
Telescope: is an apparatus used for observing distant objects.
Theodolite: is an instrument for measuring horizontal and vertical angles.
Thermocouple: an instrument based on thermo-electricity used for measuring temperatures.
Thermometer: is an apparatus used for measuring temperature.
Thermostat: It is an instrument used to regulate the temperature to a particular degree.
Viscometer: is an instrument to measure viscosity.

SCIENTIFIC APPLIANCES AND THEIR WORKING PRINCIPLES

Aeroplane: An aeroplane usually consists of the following three parts: (i) Wings, (ii) The engine and the propeller; and (iii) The tail. Working: In order to operate an aeroplane, the propeller is made to revolve at a very high speed with the help of a powerful petrol engine. The direction of the blades is so adjusted as to push the air in a backward direction, thereby producing a relative velocity between the ’plane and air—thus pushing the aeroplane in a forward direction. The push should be large enough to overcome the drag and should supply power for climbing.

Air conditioning: is the process of controlling the humidity, temperature, purity and circulation of air in a certain factory, a public building, hotels or a private house. The major aim of air-conditioning is to regulate the temperature, thereby producing a “cooling effect” on the whole. Exhaust machines are devised at a particular place for driving out waste and dirty gases, thereby completely purifying the air.

Binoculars: is an instrument used for seeing distant objects; the rays of light are twice reflected by means of right-angled prisms.

Carburettor: It is an apparatus for getting liquid fuel mixed with air as it is taken into an automobile or other like engines.

CD-Rom: It is a computer peripheral device that employs compact disk technology to store large amounts of digitized data for later retrieval.

Cellular Phone: This phone allows you to make a telephone while on the move. It can be installed in vehicles or can be carried along.

Cinematography: The principle of persistence of vision is utilised in cinematography. A cinematograph is an apparatus for projecting the pictures of moving objects on the screen. The instantaneous photographs of the successive positions of the moving body are photographed on a continuous film with the help of a special camera called the movie camera, with an automatic shutter at the rate of nearly 16 per second. The film duly developed is projected intermittently with a similar shutter as above so that it opens when the film is stationary and closes when it jerks off.

Computer: A complicated electronic machine which can perform incredibly complex calculations at incomprehensible speeds. It was invented by Charles Babbage. It can do whatever we know how to order it to perform. A computer consists of a Central Processing Unit (C.P.U.) and a number of peripheral units. A computer does not do anything which a human being cannot do. Only that it does is much faster and accurately.

Dewar Flask: is a double-walled glass flask, the inner surface of the outer vessel and the outer surface of the inner vessel of which have been silvered. The vacuum is created in the space between the two walls. This principle successfully prevents any interchange of temperature of the contents, because: (1) glass is a bad conductor (2) convection is not possible because there is vacuum between the walls and (3) a little radiation that takes place from the inner vessel is reflected by the inner surface of the outer wall.

Daniel Cell: In this a rod of zinc is placed in dilute sulphuric acid contained in a cylindrical porous pot. The porous pot and its contents are placed in a large cylindrical copper vessel which also functions as positive pole of the cell. The space between the porous pot and the copper vessel is occupied by a solution of copper sulphate. The hydrogen produced by the action of the zinc on sulphuric acid travels towards the copper electrode. On delivering its electricity to the copper, it reacts with the copper sulphate turning copper out of the solution and forming sulphuric acid. The particles of copper liberated from the solution adhere to the outer copper vessel and thus the hydrogen is rendered harmless so far as polarisation is concerned.

Diesel Engine: It is a particular type of internal combustion engine, known as compression ignition engine. The air inside the cylinder is usually compressed to over 500 lbs. per sq. in. and the temperature is attained up to 800°F. At this stage the oil is injected into the hot compressed air, which gets ignited immediately, thereby producing a continuous gas stream, which pushes the piston upward. And thereafter the engine gets into operation.

Dynamo: The origin of the electricity in a dynamo is the transformation of mechanical energy into electrical energy. It depends on the principle of electro-magnetic induction whereby a current is produced on traversing a magnetic field.

Electric Bell: In an electric bell, there is one horse-shoe electromagnet, which plays an important role. A soft iron armature which is connected to a hammer H, is placed in front of the pole pieces of the electromagnet.
One end of the coil of the electromagnet is connected to the terminal T2 while the other end is connected indirectly to the terminal T1 (i.e., through the soft iron armature which rests on the spring contact as shown in the diagram).
On connecting the terminals T1 and T2 through battery, the electromagnet attracts the soft iron piece, and the hammer H in turn strikes the gong G, which produces a sound. Simultaneously, the contact between the spring and the screw breaks which demagnetises the electromagnet and the soft iron piece falls back to make up the circuit once again. The process is repeated again and again, which produces a continuous sound.

Electric Lamp: The electric lamp is based on the principle that when an electric current is passed through a very fine metallic filament inside an evacuated glass bulb, it is heated so as to render the wire white hot or incandescent. The wire being very thin offers great resistance to the passage of the current so that considerable heat is developed and the temperature rises to make it luminous and thus emit light. The resistance generally increases as the temperature rises and soon an equilibrium is reached and there is no further rise of temperature, the amount of heat radiated by the filament being equal to that generated in it by the electric current. In order that the metallic filament shall not oxidise or rust, oxygen is removed from the bulb by pumping out air or generally some inert gas such as nitrogen or some other gas is made to fill the bulb.

Electric Motor: An electric motor is a device which converts electrical energy into mechanical energy. A D.C. motor generally consists of several segments of a coil of a wire of a large number of turns wound over a soft iron cylinder called the armature. It is mounted on an axle about which it revolves and is placed between the poles of an electromagnet called the field magnets. There are the commutator, brushes and the leads. It is based on the principle that a conductor carrying current experiences a force when placed in a magnetic field.

Electro Cardio-gram (E.C.G.): It is actually a graphic picture of the heart-beat which the physician can make use of in the diagnosis. When the heart beats, its muscles contract and this causes a change in the electrical potential of the system. This change in potential is recorded on a paper by an electrical instrument known as electrocardiograph. The electrodes are connected to the two wrists and the left leg of the patient, and the machine acts like a galvanometer, the needle of which rests on a rotating drum covered with a paper, and thus the movements of the needle are recorded.

Electromagnet: whenever an electric current passed through a coil of wire, a large number of turns, wound round a soft iron core, the iron core gets magnetised and it becomes a powerful magnet, and is known as an electromagnet. This magnetism is temporary and lasts so long as the current passes through the coil. Looking at the end of the soft iron bar if the current in the coil is clockwise in direction that end of the bar is South Pole; if the current is counter-clockwise, that end is a North Pole.

Electron Microscope: It is just analogous to optical microscope in a way that beams of electrons are focused by magnetic lenses in a similar way to the focusing of light beams in the ordinary optical microscope. Germans were the pioneer to invent the electron microscope, during the year 1930. Direct magnification up to 10,000 times is possible. Still higher magnification is possible with the Proton Microscope.

FAX: Short for facsimile, it is a device that transmits pictures, drawings, text to a similar device at the receiving end, using telephone lines.

Fibre Optics: It is a branch of physics based on the transmission of light through transparent fibres of glass or plastic. These optical fibres can carry light over distances ranging from a few inches or centimetres to more more than 100 miles (160 kilometres). Such fibres work individually or in bundles. Some individual fibres measure less than 0.004 millimetre in diameter.
Optical fibres have a highly transparent core of glass or plastic surrounded by a covering called a cladding. Light impulses from a laser, a light bulb, or some other source enter one end of the optical fibre. As light travels through the core, it is typically kept inside it by the cladding. The cladding is designed to bend or reflect-inward-light rays that strike its inside surface. At the other end of the fibre, a detector, such as a photosensitive device or the human eye, receives the light.
Uses of Optical Fibres: Optical fibres have a number of uses. Various industries use optical fibres to measure temperature, pressure, acceleration, and voltage. In fibre-optic communication systems, lasers transmit coded messages by flashing on and off at high speeds. The messages travel through optical fibres to interpreting devices that decode the messages, converting them back into the form of the original signal. Fibre-optic communication systems have a number of features that make them superior to systems that use traditional copper cables. For example, they have a much larger information-carrying capacity and are not subject to electrical interference. In addition, signals sent over long-distance fibre-optic cables need less amplification than do signals sent over copper cables of equal length.
Optical fibres are well-suited for medical use. They can be made in extremely thin, flexible strands for insertion into the blood vessels, lungs, and other hollow parts of the body. Optical fibres are used in a number of techniques that enable physicians to look and work inside the body through tiny incisions.

Fire Extinguisher: works by spraying continuous streams of carbon dioxide gas, which does not support combustion, and so acts as a fire extinguishing agent. Fire extinguisher is a medium size metallic cylinder fitted with a head-knob and a handle. At the time of emergency, the knob is struck against the floor, and carbon dioxide gas begins to evolve. Inside this cylinder a bottle of dilute solution of sulphuric acid is embedded in sodium carbonate powder. When the bottle is broken, sulphuric acid reacts with sodium carbonate to produce large quantities of the gas.

Fusion Torch: is an instrument to be evolved by the U.S. Atomic Energy Commission. It will use the power of the Hydrogen bomb to vaporise solid waste like junk-cars and bearcans, into their basic elements. The idea is based on the assumption that within a few years scientists will be able to harness the energy of the Hydrogen bomb—Controlled thermo-nuclear fusion—for use in electrical power plants.

Geiger Counter: A G.M. counter or Geiger-Muller counter is a device used for detecting and/or counting nuclear radiation and particles.

Heart Lung Machine: A machine which operates the function of the heart and lung at the time when the heart or lung is under operation. It directs the circulation of blood into body.

Incandescent lamp: If a body of sufficiently high melting point say platinum wire is raised to a high temperature, some of the radiations coming out fall within the range termed “light”. The range comprises of radiation of short wave lengths and high frequencies. When such a body is heated it emits different colours at different temperatures, and ultimately, it gives dazzling white light at 1500°C and above. So the incandescent lamp consists of a metal of a high melting point (generally tungsten) enclosed in an evacuated glass globe and heated by an electric current. The filament is either in the form of an open spiral of straight wire or in the form of a ring of coiled wire. This lamp consumes about 1.4 watt per candle.

Internal Combustion Engine: is an engine in which energy supplied by a burning fuel is directly transformed into mechanical energy by the controlled combustion of the fuel in an enclosed cylinder behind a piston. It is usually applied to the petrol- burning or Diesel oil-burning engine.

Jet Engine: The essential components of the jet engine is the Gas turbine. It drives the rotary air compressor, which supplies compressed air to the combustion chamber, where a fuel like kerosene oil or gasoline enters and burns. The hot exploded gases are then expelled to the rear in a high velocity jet exhaust. It is the reaction of the plane on this jet of ejected gases that drives it forward.

Jet Propulsion: It is now being commonly employed for propulsion of aircraft and the underlying principle is Newton’s third law of motion, that is, “to every action there is an equal and opposite reaction”. Here a gas turbine drives the rotary air compressor which supplies compressed air to the combustion chamber, where the fuel-like gasoline enters and burns. The hot exploded gases are expelled to the rear in a high velocity jet exhaust. It is the reaction of the ‘plane on this jet of fastly ejected gases that drives it forward. It has made possible supersonic speeds.

Difference between Rocket and Jet Engine: The essential difference between the propulsion of a jet engine and a rocket is that the gas turbines used in a jet engine require air to supply oxygen for the burning of the fuel. Rockets contain both fuel and an oxidizer to make them burn. Liquid oxygen is often used. So a jet engine would work only in the lower strata of the atmosphere where sufficient oxygen can be supplied by the air-compressors. The high velocity jet from a rocket is available for thrust in the upper atmosphere and even beyond the limits of our atmosphere. For rocket flights of course, the wings and rudders would be absolutely useless since there would be no air to exert force on them.

LASER: or Light Amplification by Stimulated Emission of Radiation, LASER is a device that harnesses light to produce an intense beam of radiation of a very pure, single colour. The power of the beam can be low (as in a food store laser scanner which reads prices on packages) or high (as in lasers used to cut metals). The first laser was built in 1960.

Lightning Conductor: It consists of a metal rod, the upper part of which is made up of copper with a number of conical points, the lower portion being an iron strip which extends deep into the earth’s moist layers. A lightning conductor protects the building from the effect of lightning in two ways: (i) The pointed conductors are charged by induction oppositely thus setting up an opposite wind which brings about a slow and silent discharge of the cloud. (ii) If however the lightning does strike, the discharge may be carried to the earth through the metal strip without doing any damage to the building. In ships also, lightning conductors are fixed to the masts and carried down through the ship’s keel-sheathing.

Loud Speaker: It is a device for converting electrical energy into sound energy. There are various types of loud speakers but the commonest and most efficient type used now-a-days is the moving coil type. It is based on the principle that when a varying current is passed through a conductor in a magnetic field, the conductor is acted on by a variable force and if the current is oscillatory, the conductor is set into vibrations.

Mariner’s Compass: is an apparatus which is used to guide the sailors. The needle always points north-south. It consists of a magnetised bar with a card bearing the directions viz., north, south, east etc. The card is correctly mounted above and firmly attached to the magnetised bar. When the magnet moves in relation to the ship’s course, the card automatically moves with it.

Motor-Car: A motor-car usually consists of the following working parts: (i) Internal combustion engine (ii) Gear Box (iii) Battery (iv) Carburettor (v) Dynamo (vi) Radiator.
Working: In order to operate a motor-car, the petrol from a container is ignited with the help of the battery. The vapours produced thereof are allowed to mix with air in the carburettor section, and thereafter the mixture is allowed to enter the cylinder of the internal combustion engine. The gases on expansion push the piston upwards thereby moving the crank-shaft, which in turn moves the main axle of the car. The motion of axle is controlled by the gear box.

Periscope: It is a device for viewing objects which are above the eye-level of the observer, or are placed so that direct vision is obstructed. It is usually used by the crew of a submarine to survey the ships etc., on the surface of the sea while the submarine is under water. It also enables sailors to observe objects on the other side of an obstacle without exposing themselves. It consists of a long tube, at each end of which is a right-angled prism, so situated that, by total internal reflection at the longest faces, light is turned through an angle of 90° by each prism. The light from a viewed object thus enters the observer’s eye in a direction parallel to, but below, the original direction of the object.

Phytotron: is a big machine costing two million dollars and capable of producing any type of climate to order. It has been installed in Duke University, Durham, North Carolina to facilitate studies of environmental biology—particularly growing of plants under varying climatic conditions. The machine can duplicate any set of climatic conditions from the tropical to the Arctic in the brick and glass building in which it is housed. It has six specially equipped green houses and 40 controlled plant chambers. It is a useful device for the study of environmental biology.

Radar: precisely means: Radio, Angle, Detection And Range. It is one of the interesting developments of wireless waves the principle of which has been utilised in the radio location technique or popularly known as RADAR. It is an electrical device used for the detection and location of the aircraft with the help of radio frequency waves.
Working: Wireless waves having very short wavelengths are set free in the shape of concentrated beam to flood or cover the required area of the sky. An aircraft entering that particular area is supposed to intercept the spreading waves, and an echo is reflected back to the transmitting station. In addition to detection of the aircraft, its distance from a particular place can also be calculated by recording the time taken by the wireless waves in travelling back. A discrimination between the aircraft of an enemy and a friendly nation can be made by understanding the nature of Echo.

Refrigerator: It is an apparatus or chamber for producing and maintaining a low temperature. The principle employed in the working of a refrigerator is that heat is absorbed by a liquid as it evaporates, thus producing a cooling effect. The substance commonly employed is liquid ammonia sulphur dioxide.

Rocket: The underlying principle of the flight of a rocket is Newton’s Third Law of Motion viz., To every action there is an equal and opposite reaction. It is a self-propelled vehicle which depends upon the force provided by a fuel carried along with it. As the fuel burns, products of combustion are forced out at terrific speed at the rear of the vehicle and ejection imparts motion to it in the forward direction. It has its own oxygen supply for burning the fuel and therefore, there is no dependence on air for combustion or propulsion.

Rocket Bomb: If a rocket engine is used as a missile to carry an explosive charge it is termed as a Rocket Bomb. The principle of a rocket engine is the same as that of a jet engine but unlike the jet engine it carries its supply of oxygen with it to burn the fuel and is thus independent of the oxygen of the air. The hot gases formed in the combustion of the fuel are led through a nozzle. If a quantity of gas of mass m leaves the nozzle in time t with a velocity v, the force exerted on the mass of gas and hence the force also on the rocket = mv/t. Such a rocket bomb can be hurled from a place outside our atmosphere.

Safety Lamp, Davy’s: It is based on the principle of rapid conduction of heat by a metal. In the miner’s safety lamp, the flame of the lamp is surrounded by glass and above this is a space surrounded by five copper gauzes. Inflammable gases which may be present in the mine can pass through and burn inside the lamp. The copper gauze conducts away the heat so rapidly and effectively that the ignition point of the gas outside the gauze is never reached and thus the possibility of an explosion is avoided.

Seismograph: It is an instrument used for the registration of earth tremors, and consists of principle of a heavy pendulum system, the supporting framework following the ground movements and the bob remaining at rest on account of its large inertia thereby setting up a relative movement between the two parts of the seismograph. This movement is recorded with the help of electromagnetic transducers, galvanometers and electronic amplifiers. In order to record the displacements completely, usually three seismographs are made to set at one particular station.

Sound Barrier: Before the advent of aircraft with supersonic speeds, it was apprehended that when the speeds of the aircraft and sound were equal, the compressional waves produced by the flight of the aircraft will be unable to get away and will give rise to a sound barrier which will offer a considerable resistance to the motion of the aircraft and huge structural stresses and strains will be called into play attended by great noise likely to react unfavourably on the crew. But no such effects have been observed now that the speed of the jet-propelled aircraft and rockets far exceeds that of sound.

Spring Balance: A Spring Balance is used for measuring weights. The principle involved is that the stretching in the case of a Spring is proportional to the load suspended and if a load of 1 kilogram produces a stretching of 1 cm, a load of two kilograms will stretch it by 2 cm and so on. The spring is held at the upper end and load is suspended by a hook attached to the lower end with a pointer attached to the upper end of the spring which moves over a scale.

Steam Engine: is a machine utilizing steam power through a device by virtue of which heat is converted into mechanical energy. The steam engine has two main parts: (i) boiler, and (ii) proper engine. It consists essentially of a cylinder in which a piston is moved backwards and forwards by the expansion of steam under pressure.

Stereoscope: It is an optical device that makes photographs seem to have three dimensions. An ordinary camera sees things only in a flat plane and never in the round. But if two cameras set several inches apart photograph the same object simultaneously, and if these two photographs are then mounted side by side and viewed through a combination of lenses and prisms in such a manner that the two units enter the two eyes without strain, the resulting mental picture (image) appear to have three dimensions. Everything is seen in the round, the way our two eyes normally view things. These are employed in aerial survey and in astronomical telescopes.

Submarine: may be regarded as a ship having a variable and controllable specific gravity. It is equipped with large ballast tanks (in the low, the middle and the stern of the ship) into which water can be admitted through valves so that the vessel can be made to sink when desired. On the water being expelled again by pumps worked by compressed air, the ship rises to the surface. Inside the water it is the electric motors which drive it forward and there are horizontal rudders (or hydroplanes) which are fitted on both sides of the vessel so that by tilting them the vessel is gradually submerged, the same rudders help to maintain it at a desired depth of submergence.

Tape Recorder: It is an instrument which converts sound waves into electrical impulses which are recorded as a wavy groove on the tape. When it is required to produce the voice, the electrical impulses are again converted into sound waves.

Telephone: It is a device to produce sound to enable two persons to talk to each other from distance. The circuit, which is closed when the line is connected, consists of a transmitter and a receiver connected by an electrical conductor. The transmitter which is usually a carbon microphone causes variable electrical impulses to flow through the circuit. In the telephone-receiver, these impulses flow through a pair of coils of wire wound upon soft iron pole-pieces which are attached to the poles of a magnet. An iron diaphragm near these coils experiences variable pulls and vibrates so as to produce sounds corresponding to those made into the microphone.

Telephotography: is a process by which the transmission of moving objects is made by radio from one place to another. A succession of still pictures is transmitted at the rate of twenty-five per second which gives an illusion of continuous movement. The television camera changes the light pattern of the transmitted scene into a series of electrical signals which modulate a very high frequency radio carrier wave. The received signals are changed into light variations and reassembled on the screen of a cathode-ray tube at the receiver.

Teleprinter: It is an instrument which prints automatically messages sent from one place to another. It consists of a telegraph transmitter with a type-writter key-board by which characters of a message are transmitted electrically in combination of 5 units, being recorded similarly by the receiving instrument. The receiving instrument then translates the matter mechanically into printed characters.

Telescope: A simple refracting astronomical telescope is an optical arrangement for seeing very distant objects. Two convex lenses are mounted at the ends of two tubes so that by sliding one tube within the other, the distance between the lenses can be changed and the images thereby can be focused correctly. The lens at the larger end of the telescope is of considerable focal length and is called the object glass and a smaller lens of short focal length is called the eye-piece. Parallel rays proceeding from a distant object form its real image at the principal focus of the object glass. The position of the eye-piece is adjusted so that a magnified virtual image of it is seen. Since the real image is inverted, this virtual image is also upside down—a fact of little importance in astronomical work. For viewing terrestrial objects, the real image formed by the object glass is re-inverted by another convex lens before it is magnified by the eye-piece.

Television: It is the transmission of images of moving objects by radio waves. The scene to be transmitted or its image on a photo-mosaic inside an iconoscope camera is scanned with the help of a fine beam of light traversing horizontally and vertically. The reflected pulses in the former case are picked up by photoelectric cells which convert light energy into varying electric currents, or in the latter case, the photo-mosaic with the help of suitable electrical circuits generates varying currents. These currents are amplified with the help of valve amplifiers and are then made to modulate the carrier waves from a transmitter. At the receiving station, the electrical vibrations are reconverted into light waves which are collected on the fluorescent screen of a cathode ray oscilloscope at the same rate with which they are generated at the sending station. With the help of the property of persistence of vision possessed by the eye, we can see on the screen an exact photograph of the transmitted scene.

Thermometer, Clinical: A clinical thermometer is used to note the temperature of a human body and has graduations from 65°F to 100°F. It consists of a thin glass bulb connected with a thick walled capillary tube known as the stem. There is a constriction in the bore near the bulb. When the thermometer is placed below the tongue (or in the arm-pit) of a person, mercury in the bulb gets heated and expands. The force of expansion pushes the mercury past the constriction, which thus rises into the stem. When thermometer is removed, the temperature falls and mercury contracts. But the level remains intact as the thread is now broken at the constriction. The temperature can thus be conveniently read. The mercury can be again brought into the bulb by giving it a slight jerk.

Thermos Flask (Vacuum Flask): It is used to keep hot liquids hot and cold liquids cold. The principles involved in its construction are: (i) It is made of glass which is a bad conductor of heat; (ii) As there is vacuum between the walls, convection is not possible; (iii) The outer face of the inner vessel is silvered, so there is very little radiation as polished surfaces are bad radiators. The inner surface of the outer vessel is polished which serves as a good reflector of any small radiation from the inner surface.

Tokamak T-3: is a machine designed by Russians to harness fusion reaction for peaceful purposes. A fusion reaction takes place under extreme pressure and temperatures such as exist in the core of the sun. In this machine such conditions are created by generating a hot gas or plasma. The Russians are already at work on an improved version of the machine which should achieve self-supporting generation of fusion-energy.

Transformer: It is an apparatus by which the voltage of an alternating current is made higher (step-up Transformer) or lower (step-down Transformer) or its frequency. Transformer is made up of two coils, one of a small number of turns of thick wire and the other of a great number of turns of thin wire. A current going through the first of these causes an induction current of higher voltage in the second. If the main current goes through the second one, induction current of a lower voltage is generated in the first coil.

Transistor: It is an active component of an electric circuit which may be used as an amplifier or detector. It consists of a small block of a semi-conducting material to which at least three electrical contacts are made, two of them being closely spaced rectifying contacts generally and one ohmic or loose (non-rectifying) contact. Transistors are now being used in radio receivers, in electronic computers, in electronic control equipments, in place of vacuum tubes where the required voltages are not too high. They are much smaller than their vacuum tube counterparts, consume less power and have no filaments to burn out.

Ultrasonoscope: It is a compact, diagnostic instrument designed to measure and use ultrasonic sound (with a frequency higher than 20,000 cycles per second, beyond human hearing). It emits brief bursts of ultrasound which are reflected back by bone, fluid or tissue in the body and give an “echo-gram”. The instrument can be helpful in detecting deep-seated brain tumours, defective heart valves and abnormal growths.

Videophone: The world’s first commercial videophone service was started for limited experimental use in Pittsburgh, Pennsylvania. It is as much of an advance on the ordinary telephone as the addition of sound and colour was to the movies. The visual dimension also increases the functional utility of this communication apparatus, but the trouble so far has been in designing and making videophones which will be cheap enough to be installed and used by thousands of people.

PROMINENT SCIENTISTS

Abdul Kalam, Dr A.P.J.: is credited with advancement of missile technology in India. He was honoured with Bharat Ratna award on November 26, 1997. He is known as “father of India’s Missile Technology”. Elected 11th President of India.

Alvares, Luis W.: is an American physicist teaching at the University of California, Berkeley, U.S.A. He won the Nobel Prize for Physics in 1968 for an important breakthrough he made in elementary physics in 1960 when he discovered a new resonance particle—a discovery that shattered the then prevailing notions as to how matter was built.

Anfinsen, Dr Christian B.: of the U.S.A.’s National Institute of Health, Bethseda, Maryland was one of the three co-winners of the Nobel Prize in Chemistry, 1972.

Archimedes: Greek mathematician (born in Sicily) who lived about 250 B.C. is known for the discovery of the Archimedes’ principle viz., The volume of any insoluble solid can be found by noting its loss of weight when immersed in water. He is also credited with the invention of Archimedean Screw, a cylindrical device for raising water.

Arrow, Kenneth, J.: of Harvard University, U.S.A. is co-winner of the Nobel Prize for Economics, 1972 with Sir John Richard Hicks of Oxford University. The two men are known for their pioneering contributions to general economic equilibrium and welfare theories.

Aryabhatta: (A.D. 476-520) after whom India’s first scientific satellite has been named, was a great Indian astronomer and mathematician. Among his important contributions are the recognition of the importance of the mov ement of the earth round the sun, determination of the physical parameters of various celestial bodies, such as diameter of the earth and the moon. He laid the foundations of algebra and was responsible for pointing out importance of “zero”.

Avogadro, Amedeo: (1776-1856) Italian physicist; founder of Avogadro’s hypothesis: “Equal volumes of all gases under similar conditions of temperature and pressure, contain equal number of molecules.” He also defined a molecule.

Bardeen, Prof John: of the University of Illinois (U.S.A.) is co-winner of the Nobel Prize for Physics, 1972 (with Prof Leon N. Cooper and Prof John Robert Schrieffer) for researches into the “theory of super-conductivity” usually called the BCS theory.

Barnard, Christian: South African surgeon who shot into world news in December 1967 when he completed the first heart transplant operation on Louis Washkansky.

Beadle, Dr G.: American scientist awarded Nobel Prize for medicine in 1958 for his work concerning the actual basis of heredity—the way in which characteristics are transmitted from one generation to another.

Becquerel, Henri: (1852-1908) French physicist known for his discovery in 1896 of Becquerel rays, the first indications of radio-activity; these rays were later named gamma rays. He shared Nobel Prize for Physics with the Curies in 1903.

Berzelius, J.J: (1779-1848) Swedish Chemist, known for introduction of chemical shorthand symbols and atomic weights.

Bessemer, Sir Henry: (1813-1898) English engineer. He invented the process for the manufacture of steel known after his name.

Bhabha, Dr H.J.: (1909-66) Indian scientist. He published important papers on Cosmic Rays and Quantum Theory. He was professor at the Indian Science Institute, Bangalore; Chairman, Atomic Energy Commission; Director, Tata Institute of Fundamental Research; President, Indian Science Congress in 1951 and presided at the Atoms for Peace Conference held at Geneva in 1956. He had many significant researches in structure of atom and contributed largely to the setting up of atomic reactors at Trombay (Mumbai).

Bhagvantam, Dr S.: is an eminent Indian scientist who has made a rich contribution to research in radio astronomy and cosmic rays. He has published more than 150 research papers and several books. He retired in October 1969 as the Scientific Adviser to the Ministry of Defence, and Director General of the Defence Research Development Organisation. He is an old-time associate of Sir C.V. Raman.

Bhaskaracharya: Born in A.D. 1114, he was almost the last great Hindu mathematician and astronomer until modern times. He wrote Sidhanta-Siromani in 1150 which consisted of two mathematical and two astronomical parts. Bhaskara anticipated the modern theory on the convention of signs (minus by minus makes plus, minus by plus makes minus). He also anticipated Kepler’s method for determining the surface and volume of sphere.

Bhatnagar, Dr Shanti Swarup: (1895-1955) great Indian scientist. He was Director of Council of Scientific and Industrial Research (C.S.I.R.). A chain of National Laboratories has been established in the country due to his able organisation and unbounded energy.

Bohr, Neils: (born 1885) Danish Physicist. He was awarded Nobel Prize for Physics in 1922. He greatly extended the theory of atomic structure of devising an atomic model in 1913 and evolving theory of nuclear structure; assisted America in atom bomb research.

Borlaug, Norman Ernest: American agricultural scientist and winner of the Nobel Prize for Peace in 1970. He was one of those who laid the groundwork of the Green Revolution.

Bose, Sir J.C.: (1858-1937) Eminent Indian physicist and Botanist; founder of Bose Research Institute, Calcutta. Inventor of crescograph which is used to magnify movements made by plants.
Bose, S.N.: Eminent Indian scientist who won fame by expounding the Bose-Einstein theory, which is concerned in detection of a group of nuclear particles—named after him ‘Boson’ in recognition of his contribution to the subject; contributed to Plank’s law. Professor of physics, Calcutta University; nominated member to the Council of States. Awarded Padma Vibhushan in 1954. He died on February 4, 1974.

Boyle, Robert: (1627-1691) Irish natural philosopher; one of the founders of modern chemistry and Boyle’s law: “Temperature remaining constant, volume of a given mass of gas varies inversely as its pressure.”

Bragg, Sir William: (1862-1942) British physicist known for researches on the behaviour of crystals with regard to X-rays incident upon them. Author of the book: “Atomic Structure of Minerals”.

Cavendish, Henry: (1731-1810) English physicist and chemist; he discovered properties of hydrogen in 1766 and identified it as an element.

Chadwick, Sir James: (1891-1974) British physicist. He discovered the particle in an atomic nucleus which became known as the neutron, because it has no electric charge.

Chandrasekhar, Dr Subramanian: He was a scientist of Indian origin settled in the U.S.A., who shared the 1983 Nobel Prize for physics with an American, William Fowler. He was one of the most outstanding astrophysicist of the world.
His theory of stellar evolution—the birth and death of stars—is more than 30 years old. When he first propounded his finding that old stars just collapse and disappear in the light of denser stars of low light, the world’s top-flight astronomers laughed at him and rejected his theory. A disappointed Dr Chandrasekhar left Trinity, Cambridge, to pursue his research in the University of Chicago. Over the next two decades the “Chandrasekhar Limit” became an intrinsic part of text-books on advanced astrophysics. Global recognition and awards poured in, and the 1983 Nobel Prize tops a remarkable career spanning almost half a century.

Charak: (c.A.D. 80-180) was a court physician to Kushan king Kanishka. His writings are invaluable in the study of Hindu medicine.

Charles, Jacques Alexander Cesar: (1746-1823) a French scientist of great repute. He was the first to make a balloon ascension with hydrogen. He is known for his work on the effect of temperature on the volume of gases.

Clarke, Arthur C.: He is known for his suggestion of the concept of Geostationary Orbit.

Clark Maxwell, James: (1831-79) British physicist. His theoretical work prepared the way for wireless telegraphy and telephony. His principal works include: Perception of Colour, Colour Blindness, Theory of Heat, Electricity and Magnetism, Matter and Motion.

Claude, Albert: is a biologist of Luxembourg who shared the 1974 Nobel Prize in Medicine. His field of research relates to causes and treatment of cancer.

Columbus, Christopher: (1446-1506) A well-known Italian navigator set out on his first voyage in 1492; he discovered West Indies Islands, Cuba and Bahamas; he also discovered South America in 1498.

Cooper, Leon N.: Of the Brown University, Providence, Rhode Island (U.S.A.) was one of the three co-winners of the Nobel Prize in Physics, 1972 for researches into the theory of super-conductivity.

Copernicus: (1413-1543) A prominent astronomer of Poland who discovered the “Solar System”.

Cornforth, John Warcup: co-winner of the 1975 Nobel Prize in Chemistry is a deaf professor. He is an Australian living in England. His chief distinction is mapping out the formation of cholesterols which he calls “a great discovery” and contains the key to, for instance, sex hormones.

Curie, Madame Marie: (1867-1934) Polish physicist and chemist; famous for her discovery of radium was awarded Nobel Prize in chemistry in 1911 and shared Nobel Prize in physics in 1903 with her husband and Becquerel.

Dalton, John: (1766-1844) British scientist. He was founder of the Atomic Theory and law of Multiple Proportions.

Darwin, Charles: (1809-82) was the British scientist who discovered the principle of natural selection. His famous work is “The Origin of Species”.

Davy, Sir Humphrey: (1771-1829) British chemist. First to apply electric current for the isolation of metals. Studied anaesthetic action of nitrous oxide, properties of chlorine and alkali metals.

Debreu, Gerard: Gerard Debreu of the University of California at Berkeley, who has been awarded the 1983 Nobel memorial prize in economics is known for his research on market equilibrium in which he “incorporated new analytical methods into economic theory”.
Mr Debreu has expanded on a mathematical model designed by the two men in the early 1950s that confirmed the logic of Adam Smith’s “theory of general equilibrium” in which prices supply and demand tend to reach a balance within a free market economy.

Delbrueck, Dr Max: is a German-born American doctor working at the California Institute of Technology. He was one of the three American co-winners of the Nobel Prize for Medicine, 1969 for discoveries in molecular genetics.

De Vries: is known for Mutation theory.

Dhanvantri: a great physician during the reign of Chandragupta Vikramaditya (375-413 A.D.).

Dhawan, Prof Satish: He is former Chairman of the Indian Space Research Organisation (ISRO). Under his dynamic leadership India entered Space Age by launching “Aryabhata”, a scientific satellite, into space on April 19, 1975.

Edelman, Dr Gerald Maurice: of U.S.A. is co-winner of the Nobel Prize for Medicine, 1972. He is known for researches into the chemical structure of blood-proteins or antibodies which shield the human body against infection. He shared the prize with Dr Rodney Robert Porter of Oxford. The two Nobel-laureates were able to break the giant molecules formed by antibodies into their component sections.

Edison, Thomas Alva: (1847-1931) American inventor of Dutch-Scottish parentage. He started life as a newsboy and then a telegraph operator. His inventions include: phonograph, the incandescent lamp, a new type of storage battery, an early form of cinematography etc.

Einstein, Prof Albert: (1879-1955) was German-Swiss world-famous scientist known for his theory of relativity. He was awarded Nobel Prize for his work on photoelectric effect.

Faraday, Michael: (1791-1867) An eminent English scientist; showed great prominence in the field of electromagnetism; discovered the laws of electrolysis and wrote a number of useful books on the subject.

Fleming, Alexander: (1881-1955) British bacteriologist. His notable discovery was lysozyme (1922), followed by penicillin (1929)—an antibiotic drug.

Fleming, Sir John Ambrose: (1849-1945) British physicist and engineer who was pioneer in the development of the telephone, electric light and radio.

Fraunhofer: German physicist. He gained prominence on the researches of ‘Light’ while performing spectrum-analysis of Sunlight; he discovered the spectrum to be crossed with some indifferent black lines. And the lines are so named as Fraunhofer Lines.

Freud, Sigmund: (1856-1939) originator of psycho-analysis, born of Jewish parents. Works: The Interpretation of Dreams; The Psychopathology of Every-day Life; The Ego and the Id; Civilization and Its Discontents.

Gabor, Dr Dennis: Who won the 1971 Nobel Prize award for Physics is a 71-year old British electrical engineer working as a scientist in the U.S.A. He was cited for his “invention in development of the holographic method”—three dimensional photography. Dr Gabor was the 16th Briton to have won the Nobel Prize in Physics. He was born and educated in Hungary. He later worked as research engineer in Germany and came to join the staff of the Imperial College in London in 1949. He invented holography in the late forties. But the science became fully developed with the coming of the laser in 1960. A holographic image is so lifelike that a viewer can see around things in a holograph by moving his head just as he looks around the real object.

Galileo: (1564-1642) Italian scientist. He was professor of mathematics. His view that all falling bodies, great or small, descend with equal velocity, made him unpopular with the orthodox scientists. He improved telescope and with it was the first man to see the satellites of Jupiter.

Gell-Mann, Prof Murray: was the recipient of the 1969 Nobel Prize for Physics. He is a teacher in the California Institute of Technology. Born in New York in 1929, Prof Gell-Mann has been the leading theorist in elementary particle research for the last 15 years. He was the 28th American to be awarded the Nobel Prize for Physics in which the U.S.A. now leads. The Nobel Prize was given to him for “his classification of elementary particles and their interactions”.

Goddard, Robert H.: was an American who mentioned the possibility of shooting a rocket to the moon in a paper entitled “A Method of Reaching Extreme Altitudes” published by him in 1919. By 1926 he had put some of his ideas into practice. He is looked upon as one of the pioneers of space research.

Graham, Thomas: (1805-1914) Scottish chemist called the “father of colloidal chemistry”. He did remarkable work on diffusion of substances in solution.

Heisenberg: is known for his theory of Uncertainty Principle.

Hahn, Otto: was a German pioneer of nuclear research. He won the Nobel Prize for Chemistry in 1944. It was Hahn who had proved in 1938 that atomic fission can be achieved by bombarding uranium with neutrons. The discovery revolutionised atomic science.

Hall, Charles Martin: (1863-1914) American chemist who discovered the modern method of extraction of aluminium by electrolysis of bauxite in 1886.

Harvey, William: (1578-1675) English physician who discovered the circulation of blood.

Herzberg, Dr Gehard: has been awarded the 1971 Nobel Prize in Chemistry, for his researches in atomic and molecular structures, particularly free radicals. He is the first Canadian to win a Nobel Prize in Chemistry.

Holley, Robert: Co-winner of the Nobel Prize for Medicine, 1968, belongs to Cornell. His researches into the genetic code and its function in building protein led to the discovery of the complete structure of a transfer RNA molecule and the way it works.

Hopkins, Sir Frederick Gowland: He was an eminent English biochemist famous for his important work on proteins and vitamins. He was awarded the Nobel Prize in medicine in 1929 for the discovery of Vitamin D.

Hoyle, Fred: is a British scientist and science-fiction writer who won the £ 1,000 Kalinga Prize in 1968.

Jenner, Edward: (1749-1823) Eminent English physician who discovered the vaccination system of alleviating small pox.

Josephson, Dr Brian: is a British scientist who co-shared the 1973 Nobel Prize for physics for “his theoretical predictions of the properties of a super-current through a tunnel barrier, in particular those phenomena which are generally known as Josephson effects”.

Joshi, Prof S.S.: He has done commendable work on physical and chemical reactions under electric discharge on active nitrogen; colloids; hydrogen peroxide; permanganates and a phenomenon called “Joshi Effect”.

Joule, James Prescott: (1874-1937) a great English physicist who first demonstrated that mechanical energy can be converted into heat.

Kepler, Johannes: (1571-1630) German astronomer. He discovered 3 laws of planetary motion that bear his name viz., (1) The orbit of each planet is an ellipse with the sun at one of the foci; (2) the Radius vector of each planet describes equal areas in equal times; (3) The squares of the periods of the planets are proportional to the cubes of their mean distances from the sun.
Kepler had evolved a set of laws governing man in space with rare prescience. In a kind of allegory, he referred to the dangers of solar radiation, the need to overcome gravitational resistance, gravitational capture of spacecraft by the moon etc. What he wrote nearly 360 years ago was, however, little understood and his family was persecuted for it. His mother had to die in jail having been condemned as a witch.

Khorana Hargobind: who shared with two others the 1968 Nobel Prize for Medicine is an Indian by birth and an American by domicile. He deciphered the genetic code and later created an artificial gene.

Krishnan, Dr K.S.: (born 1898) collaborated with Sir C.V. Raman in the discovery of “Raman Effect”. President, Indian Science Congress, 1949; delegate to several international scientific conferences; Director, National Physical Laboratory, New Delhi.

Lavoisier, A.L.: (1743-1794) French chemist; established law of Indestructibility of Matter, Composition of Water and Air.

Lister, Joseph: (1827-1912) British surgeon. He was the first to use antiseptic treatment for wounds; introduced antiseptic surgery.

Lodge, Sir Oliver Joseph: (1851-1940) British physicist. He is chiefly known for his researches on radiation, and the relation between matter and ether.

Lovell, Sir Bernard: He is professor of Radio-Astronomy in the University of Manchester and is also Director of the Jodrell Bank Observatory. He remains very much in the news for tracking space-ships.

Lysenko: Author of Agro-biology, Lysenko gained fame as a Soviet geneticist. In 1948, he declared the Mendelian theory obsolete and erroneous.

Marconi: (1873-1937) Italian scientist; pioneer in wireless telegraphy and radio.

Max Planck: He was a German theoretical physicist who formulated the quantum theory which revolutionized physics. He was awarded the Nobel Prize in 1918.

Mendel, Johann Gregory: (1822-84) Austrian monk and naturalist whose discovery of certain principles of inheritance (heredity) is of deep significance in the study of biology.

Mendeleef, D.I.: (1834-1901) a Russian chemist, founder of periodic law and famous for the development of petroleum and other industries in Russia.

Meyer, Victor: (1848-1897) discovered a method to determine the molecular weights of volatile substances.

Morley, Edward William: (1818-1923) American chemist and physicist best known for his work in determining the composition of water by weight.

Moseley, Henry G.: (1887-1915) British physicist who did valuable work on atomic structure, and in 1913, devised the series of atomic numbers.

Nagarjuna: the renowned chemist of Buddhist era whose works are mostly preserved in China and Tibet. A great Philosopher and Chemist. He makes a mention of crucibles, distillation stills, sublimation, colouring process, alloying of metals, extraction of copper and use of many metallic oxides in medicines. About chemistry he said, “As long as the science of chemistry prevails, let hunger, pain and poverty not torment men.”

Nag-Chowdhury, B.D.: an eminent Indian nuclear physicist, known all over the world.

Narlikar, J.V.: Indian scientist; co-author of Hoyle-Narlikar Theory of continuous creation. The theory of which he is co-author has been hailed as supplying some important missing links in Einstein’s theory of Relativity. The new theory of gravitation propounded by both the scientists, Narlikar and Hoyle, shows that gravitation is always attractive and there is no gravitational repulsions.

Newton, Sir Isaac: (1642-1727) was the British natural philosopher. He discovered binomial theorem; the differential and integral calculus. He expounded the universal law of gravitation. He is author of Principia Mathematica.

Nirenberg, Dr Marshall: is a U.S. molecular biologist who shared the 1968 Nobel Prize for Medicine with Dr Robert Holley and Dr Hargobind Khorana. Nirenberg is the author of a very simple but ingenious experiment which helped a great deal in clarifying the general character of the genetic code.

Oberth, Hermann: is a Rumanian-German Professor who is credited with establishing the experimental basis of modern rocketry. In 1923, the publication of his book, “The Rocket into Interplanetary Space” aroused great interest in space travel.

Ohm, George Simon: (1787-1854) physicist and mathematician; discovered the law known as Ohm’s Law.

Onsager, Lars: is a U.S. Professor who became a Nobel laureate in 1968 by winning the prize for Chemistry “for the discovery of the reciprocal relations bearing his name which are fundamental for the thermo-dynamics of irreversible processes”.

Paraceisus: (1493-1541) a Swiss mystic and chemist. He was the first to employ laudanum and antimony in Pharmacy.

Parson, Sir Charles: (1854-1931) British engineer; inventor of Parson steam turbine.

Pasteur, Louis: (1822-95) He was a French chemist who discovered the causes of fermentation in alcohol and milk and founded the Pasteur Institute in 1888. He made researches in silkworm disease, anthrax, and hydrophobia.

Pauling, Linus: American bio-chemist. He applied the quantum theory to chemistry and was awarded Nobel Prize (1954) for his contribution to the electrochemical theory of valency.

Porter, Dr Rodney Robert: is Professor of Biochemistry in Oxford University. Dr Porter is known for his discoveries relating to the chemical structure of antibodies.

Priestley, Joseph: (1733-1804) British Chemist; discovered oxygen and methods of collecting gases.

Pythagoras: is known as the father of Geometry.

Rainwater, James: of the U.S.A. who co-shared the 1975 Nobel Prize in Physics is known for the development of the theory that atomic nucleus is not always spherical but can also be egg-shaped which has no immediate practical meaning but is extremely essential to scientists.

Ramanna, Dr Raja: former Director of Bhabha Atomic Research Centre at Trombay. He was one of the Indian scientists associated with staging India’s first nuclear blast at Pokhran on May 18, 1974.

Raman, Sir C.V.: (1888-1970) Eminent Indian Scientist (F.R.S.) National Professor of Physics and founder Director of Raman Research Institute, Bangalore. He was awarded Nobel Prize for his discovery of ‘Raman Effect’ (Feb 28, 1928). His work on study of crystal structure is of unique importance. Feb 28 is celebrated every year as National Science Day.

Ramanujan, Srinivas: (1887-1920) Indian mathematician who contributed to the theory of numbers, theory of partitions, and the theory of continued fractions.

Ramsay, Sir William: (1852-1916) English chemist who discovered helium and later on neon, argon in collaboration with Rayleigh and others. He was awarded Nobel Prize in 1904.
Rao, Prof U. Ramachandra: is the Director of Indian Scientific Satellite Project (ISSP) at Peenya near Bangalore.

Ray, Sir P.C.: (1861-1944) founder of Indian Chemical Society and Bengal Chemical and Pharmaceutical Works Ltd., and author of ‘Hindu Chemistry’. His work about nitrous acid and its salts deserves special mention.

Richards, T.W.: He was Prof of Chemistry at Harvard University in U.S.A. He did notable work in the accurate determination of atomic weights and was awarded Nobel Prize in 1916.

Roger Bacon: (1214-1294) He was inventor of Gun Powder and founder of experimental science; man of remarkable gifts and inventive power.

Rontgen, W. Konrad: (1845-1923) German physicist. He discovered X-rays, also called Rontgen rays. He was awarded the first Nobel Prize in 1901 for discovery of X-Rays.

Ross, Ronald: (1857-1932) leading British physician who discovered the cause of Malaria; awarded Nobel Prize for medicine in 1902.

Rutherford, Daniel: (1749-1819) a Scottish scientist who is given the credit for the discovery of nitrogen.

Rutherford, Lord: (1871-1937) won a Nobel Prize for his work on structure of atom and radio-activity.

Ryle, Sir Martin: of the U.K. who shared the 1974 Nobel Prize in Physics is known for the development of “aperture synthesis” technique designed to identify stellar objects through radio signals.

Saha, Dr Meghnad: (1893-1956) late Palit Prof of Physics, University College of Science and Technology, Calcutta University—well known for his researches in nuclear physics, cosmic rays, spectrum analysis and other branches of theoretical physics.

Sanger, Dr Frederik: British scientist awarded Nobel Prize in Chemistry in 1958 for his work in determining the composition of the insulin molecule. By his discovery he has put science a step forward towards knowing how disease attacks the human body. In 1980, he became only the fourth person ever to be awarded a second Nobel Prize.

Sarabhai, Dr Vikram A.: former Chairman of India’s Atomic Energy Commission and the Indian Space Research Organization (ISRO) died on December 30, 1971. Dr Sarabhai was an eminent physicist mainly interested in the astrophysical implications of Cosmic Ray Time Variations.

Sen, P.K. (Dr): is the Indian surgeon who performed Asia’s first heart transplant operation in Mumbai.

Simpson, Sir James Young: (1811-70) British physicist who was largely instrumental in the introduction of chloroform as an anaesthetic in 1847.

Soddy, Frederick: (1877-1956) British physical chemist. He was a pioneer of research into atomic disintegration. He coined the term “isotopes”; did classic work on radioactivity.

Solvay, Earnest: (1838-1922) Belgian chemist known for devising a process known after his name for manufacture of sodium carbonate.

Susruta: was a fourth century Hindu surgeon and physician. He wrote an important book on medicine and also a thesis on the medical properties of garlic.

Sutherland, Dr Earl W.: was the recipient of the Nobel Prize for Medicine, 1971. He is credited with the discovery that the hormones in the human body produce another substance known as cyclic A.M.P., which activates them and controls the body’s cells. He has demonstrated that changes in the level of cyclic A.M.P. in the body can influence its disease-resisting capacity. This discovery opens up new vistas for the development of drugs that can treat diseases which have so far been regarded as incurable.

Teller, Edward (Dr): is a U.S. nuclear scientist who has played a major role in developing the hydrogen bomb. He is in fact known as the “father of the H-bomb”.

Thomson, Sir J.J.: (1856-1940) British physicist. He discovered the electron which inaugurated the electrical theory of the atom. He is regarded as the founder of modern physics.

Tsiolkovsky: was a Russian teacher who in 1903 published a treatise presenting remarkably accurate calculations on rocket dynamics and space-travel. He is looked upon as the earliest among the pioneers who laid the foundations of space exploration. The Russians call him the “Father of Rocketry”.

Varahmihira: (505-587) was a distinguished Indian astronomer, mathematician and philosopher. He was one of the nine gems of the court of king Vikramaditya.

Verne, Jules: (1828-1905) French science-fiction writer was author of “From the Earth to the Moon” published in 1865. The book carried a more or less accurate prediction of the launching and flight of Apollo-8.

Volta, A.: (1745-1827) Italian physicist and pioneer of electrical science; invented voltaic pile, the electrophorus and electroscope. The volt is named after him.

Voronoff, S.: Russian scientist best known for his method of preventing or delaying senility by grafting healthy animal glands, into the human body.

Watson and Crick: known for DNA double helix.

Watson-Watt, Sir Robert: British physicist. He developed radar.

Watt, James: (1736-1819) was Scottish engineer. He invented steam engine.

Yukawa, Dr H.: (born 1907) predicted a new particle meson which holds the protons and neutrons of the atomic nucleus. He is the first Japanese to win the Nobel Prize in Physics (1949).

Pioneers in Science

Pioneers in Science
Inventions and discoveries in Physics and Chemistry
Anderson—Discovered positive electrons.
Archimedes—Discovery of the Principles of lever and of specific gravity; invention of the famous Archimedean screw.
Avogadro—An Italian scientist known for Avogadro’s Hypothesis.
Bacquerel—Radio-activity of uranium.
Baird—Television.
Baron Napier—Logarithms.
Benjamin Franklin—Invented lightning conductor.
Bessemer—Steel smelting process.
Bhabha, Dr H.J.—Research in Cosmic rays and Quantum theory.
Binet—Intelligence Test.
Birbal Sahni—Researches in Botany.
Bose, J.C.—Invented Crescograph and published many works on plant physiology. He discovered that plants have sense and perception.
Bose, S.N.—Discovery of a group of nuclear particles named after him “Boson”.
Boyle—Boyle’s law; Pressure x volume = constant at a constant given temperature. Boyle was the greatest scientist of England in his time.
Bohr—Electron Theory—Atomic structure.
Braun, Dr Wernher von—space flying.
Bunsen—Invention of the spectroscope.
Carothers—Nylon plastics.
Cavendish—Discovery of chemical composition of water; discovery of hydrogen (Inflammable Air); ‘rare gases’.
Chadwick—Discovery of the neutron.
Chandrasekhar—Mathematical Astrophysics.
Charles Darwin—Theory of Evolution; Origin of Species.
Clarke, Arthur C.—Concept of Geostationary Orbit.
Curie, Madame—Discovery of radium.
Dalton—Atomic theory; laws of chemical combination; law of partial pressures; the law of multiple proportions.
Democritus—Greek philosopher—(Atomic theory).
Dewar—Invented cordite, liquid oxygen and introduced thermos flask.
Einstein—Theory of relativity.
Euclid—Science of geometry.
Fahrenheit—Fahrenheit mercury thermometric scale in which freezing point is –32° and boiling point is 212°.
Faraday—Electromagnetic induction and laws of electrolysis.
Fermi—Discovered artificial splitting of atoms.
Freud—Doctrine of Psycho-analysis.
Gay Lussac—Law of gases.
Gauss—System of absolute electric measurements.
Good Year—Discovered the art of vulcanising rubber.
Herschel, William—Discovered the Planet—Uranus.
Hertz—Electrical waves.
Hippalus—Founder of scientific astronomy.
Hoffmann—Discovered the first aniline dye.
Kelvin, Lord—Dynamical theory of heat.
Khorana, Dr Hargobind—Deciphering the genetic code.
Kodak—Film and photographic goods.
Lablanc—Manufacture of washing soda.
Lawrence—Invention of cyclotron.
Lockyer—Helium gas.
Louis Braille—Perfected his system of reading and writing for the blind.
Marconi—Wireless telegraphy; radio.
Maria-Montessori—‘Montessori’ method of teaching children.
Maxwell—Electro-magnetic Theory of Light.
Meghnad Saha—Effect of pressure on Radiation through bodies.
Mendel—Laws of heredity.
Mandeleev—Periodic Table.
Morse—Morse system of electric telegraphy.
Newton—Laws of gravitation; Law of Motion.
Nobel—Dynamite.
Oliver Lodge—Physicist. Researches in wireless communications.
Oppenheimer—Researches in atomic theory.
Otto Hahn—Discovery of uranium fission.
Parkes—Celluloid.
Parsons—Steam turbine.
Pavlov—Theory of Conditioned Reflex.
Perkin—‘Mauve dye’.
Pitman—Founded the Pitman system of phonographic shorthand.
Planck—Quantum theory.
Plimsoll—Introduced a line of demarcation on the ships beyond which the ships cannot be loaded.
Priestley—Discovery of Oxygen.
Raman, C.V.—“Raman Effect” on polarisation of light and theories on crystals and diamond formation.
Ramanathan—Molecular scattering of light in fluids.
Ramanujam—A great Indian mathematician.
Ramsay—Discovery of Inert gases such as Argon, Neon, Helium etc.
Ray, P.C.—Researches in chemistry.
Regnault—Experiments in regard to the physical properties of bodies and their relation to heat.
Roger Bacon—Gun powder.
Rontgen—Discovery of X-rays.
Rohmkorff—Induction coil.
Rutherford—Atomic Research; succeeded in splitting the atom for the first time in 1918.
Shalimar—Paints.
Stephenson—British engineer and pioneer in Railways. He was the first to put a locomotive on the line that was able to draw a train of 31 carriages.
Thomson, J.J.—Discovered electron.
Travers—Discovery of Neon gas (Working with Ramsay).
Urey—Discovery of Heavy Hydrogen.
Volta—Current electricity and electric battery.

Pioneers in Mechanical Inventions and Discoveries
Austin—Motor Car.
Bell, Graham—Telephone.
Berliner—Microphone.
Brequet—Helicopter.
Bushwell—Submarine.
Caxton—Printing Press.
Colt—Revolver.
Daimler—Gas engine.
Davy—Miner’s Safety Lamp.
Diesel—Internal Combustion engine (Diesel engine).
Dunlop—Pneumatic tyre.
Edison—First electric bulb and gramophone.
Faraday—Dynamo.
Fick—Law of Diffusion—Fick’s Law.
Frank Whittle—Jet propulsion.
Fulton—Stream boat.
Galileo—Telescope.
Gillette—Safety razor.
Guttenburg—Art of Printing.
Hoe—Rotary Printing Press.
Howe—Sewing Machine.
Huygens—Pendulum clock.
James Watt—Steam engine (patented in 1769).
Landstrom, J.E.—Safety Matches.
Macmillan—Bicycle (1842).
Mauser—Magazine of rifle.
Mercator—Celestial and a terrestrial globe.
Montgolfier—Balloon (1883)
Pascal—Calculating Machine.
Puckle, James—Machine gun
Shockley—Transistor.
Sholes—Typewriter.
Stephenson—Railway engine.
Swinton—Military tank.
Torricelli—Barometer.
Watt, Robert Watson—Radar.
W. & O. Wright (Wright Brothers)Aeroplane (1903).
Waterman—Fountain pen.
Zeiss—Lenses; Camera.

Pioneers in
Medical Inventions and Discoveries
Banting—Insulin (as a palliative for diabetes).
Barnard, Christian—Replacing the human heart.
Brahmchari, U.M.—Cure of Kala-a-zar fever.
Davy—Isolation of metals by electricity; studied properties of chlorine.
Domagk—Sulpha drugs as bactericides.
Eijkman—Cause of Beri-Beri.
Finsen—Discovered curative effect of ultra violet rays; photography.
Fleming, Alexander—Penicillin (in 1929).
Harvey—Circulation of blood.
Hahnemann—Homoeopathy (founder).
Hopkins, Frederick Gowland—Vitamin D.
Jenner—Smallpox Vaccination.
Koch—Tubercle Bacillus.
Lainnec—Stethoscope.
Lister, Lord—Antiseptic treatment.
Pasteur, Louis—Treatment of rabies; cure of hydrophobia.
Ronald Ross—Malaria Parasite.
Salk, Jonas E.—Anti-polio Vaccine.
Simpson and Harrison—Chloroform.
Waksman—Streptomycin.