Air Cooler: An apparatus for cooling the air. Here air is blown through water and atmosphere cooled.

Altimeter: An instrument used in aircrafts for measuring altitudes

Ammeter: An instrument used for measuring electric current.

Anemometer: An instrument to measure the speed and pressure of the wind.

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Beaufort scale: It is used to measure wind force.

Barograph: An instrument which registers automatically the altitude reached by an aeroplane.

Barometer: An instrument to measure atmospheric conditions and changes.

Callipers : A compass with legs for measuring the inside or outside diameter of bodies.

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Calorimeter: An instrument used for measuring quantities of heat.

Carburettor: An apparatus for charging air with petrol vapours in an internal combustion engine.

Cinematograph: An apparatus for projecting pictures on the screen in so rapid a succession that picture seems to be in motion.

Crescograph: An instrument for recording electrically the response of living matter to various kinds of stimuli.

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Cardiograph: Is a medical instrument for tracing heart movements.

Chronometer: Is a clock to datermin longitude of a vessel at sea.

Cyclotron: It is an apparatus for smashing atoms.

Computers: These are data-processing machines, which provide the information according to the requirements.

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Dictaphone: A trade name for a tape recorder.

Dynamo: A machine used for transforming mechanical energy into electrical energy.

Electric Motor: Machine for using electricity as a motive power.

Electrometer: An instrument for measuring electrical potential differences.

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Epidiascope: For projecting fLms as well as images of opaque articles on a screen.

Eudiometer: It is a glass tube for measuring volumes changes in the chemical reactions between gases.

Fathometer: Is an instrument used for measuring depth of the ocean-

Gramophone: A machine for reproducing recorded sound.

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Hydrophone: An instrument for measuring the density of liquids with that of water, hygrometer: An apparatus for measuring the humidity of air. Internal Combustion Engine: An engine in which heat energy added the air within the working cylinder and converted into mechanical work through the medium of a piston or by a turbine rotator. Lactometer: A typical hygrometer for testing pure milk. Laser: A device to throw a thin beam of light that is carried over great distances.

Water Meter: For measuring gallons of water consumed.

Voltameter: For measuring electricity consumed.

Magneto: A part of the motor car that converts mechanical energy into electrical energy.

Manometer: For determining the pressure of a gas. Micrometer: An instrument for measuring distance of angles. Microphone: An instrument which intensifies and renders audibly the faintest possible sound.

Microscope: An optical instrument for producing greatly magnified images of very small objects.

Periscope: Optical instrument used in trench warfare and in submarines for enabling an observer to see surrounding objects from a lower level.

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.

Pyrometer: Is an instrument for measuring high temperatures. Radar: An instrument to detect the presence of enemy aircraft, submarine, etc., and also to determine its direction, distance and speed. Radiogram: A combined radio and gramophone. Refract meter: It is an instrument to measure refractive indices. Radiometer: An instrument for measuring the radiant energy of light and heat.

Samaphore: System of signalling between two places generally ships. Seismometer: It is an apparatus for measuring the origin of earthquakes.

Sextant: An instrument for measuring angle. Spark Plug: Device for producing an electric spark to set off combustion in the cylinder of a petrol engine.

Stethoscope: A doctor’s tool to listen to the beat of the heart. Stereoscope : A binocular optical instrument through which a double Photograph taken from two slightly different angles by two lensed cameras is viewed.

Speedometer: An instrument which registers the speed of the vehicle

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.

Telstar : It is a space communication satellite developed by Bell for overseas communications. It was launched on July 10, 1962 from Cape Kennedy (U.S.A.). Telstar, in addition to telephone calls, enables television microwave transmissions to be made from and to any country with a receiving and transmitting station.

Telemeter: Is an apparatus for recording physical events happening at a distance.

Theodolite : An instrument for use in land surveying for measuring vertical and horizontal angles.

Thermometer: It is an instrument to measure the temperature.

Thermionic valve : Used in wireless telegraphy and radio broadcasting.

Thermostat: It is an instrument which controls temperature automatically. It is used in refrigerators, air-conditionsers, geysers etc.

Transformer: It is an electric apparatus which is used to convert high voltage to low and vice versa.

Tachometer: An instrument for measuring the speed of aeroplanes, motors, etc.

Television: It is the transmission of images of moving objects by radio waves.

Telescope: An instrument designed to view the distant object easily.

Teleprinter : An instrument which prints automatically messages sent from one place to another on telegraph lines.

Viscometer: Is an instrument to measure viscosity.

Voltmeter: It is an instrument to measure the potential difference across two points of an electrical circuit.

Voltameter : It is an apparatus for producing electrolysis in liquids,

Wattmeter: Is an instrument for the direct measurement of power in watt of an electrical circuit.