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How to ? Science And Technology Question & Answer – Part 6

Science Question and Answers Riddle Part 6

In How to know, about science and technology series we will provide you information about science and technology, We are in making part of series and every part will contain 8-10 scientific questions and answer !

HOW DOES A PHOTOCOPIER WORK?

A photocopier makes instant copies of pages of books and other documents. You place the page on a
glass plate and press a button. The page is lit up from inside the machine. An image of the page is then produced, made of particles of dark powder.

There are two main kinds of photocopiers, Xerographic copiers use ordinary paper while electrostatic copiers require special coated paper.

The paper passes through a bath of toner, and the particles cling to the charged parts of the paper to produce the copy.

WHAT DOES A WORD PROCESSOR DO?

A word processor is a kind of A electronic typewriter. You type in words and they appear on a screen, Then the processor types all the words onto paper automatically. It types as many copies as required, and you can make changes without having to type everything out again.

The word processor is in fact a kind of computer. It has a memory which stores all the words that you type into it at the keyboard. Then, whenever required, the processor fetches the words from its memory and sends them to its typing unit to be typed onto paper.

HOW ARE STATUES MADE?

A sculptor may carve a statue from a block of stone or of wood. Using a hammer and chisel, he or she chips away at the block to form the statue. Metal statues are first made in clay, and a mould is made. The statue is cast by pouring molten metal into the mould and leaving it to set.

A sculptor who carves a statue has to take great care not to cut away too much stone or wood from the block. Then the final statue may be delicately polished to make
the surface smooth and shiny.

HOW ARE STATUES AND MODELS CAST?

First a clay figure is made, then a mould is made by covering the figure in plaster. The figure is removed, and the middle of the plaster mould is almost filled with a core of material. Then molten metal is poured between the mould and the core.

The ‘lost-wax’ process is often used to cast metal statues. Hot wax is poured into a plaster mould of the clay figure. Then liquid metal is poured through a hole into the mould. It melts the wax, which runs out of the mould, and then sets to produce a hollow metal statue or model.

HOW DOES A CAMERA TAKE PICTURES?

The lens on the front of a camera makes a picture appear on the film inside the camera. By looking into the viewfinder, you can see the picture that the camera will take. You then press the shutter release to take the photo.

The light rays that come from an object in front of the camera are refracted (bent) by the lens to project an image of the object on to the film. The image is upside down and back to front, but the picture is seen the right way when a print or slide is made. When the shutter release is pressed, the shutter opens for a fraction of a second and exposes the film.

HOW DOES A FLASH WORK?

The bulbs in a flash-cube contain A metal wire or foil and a small tube of powder. When the shutter release
is pressed, it makes a spring strike the tube and fire the powder. This heats the wire or foil in the bulb, making it burn brightly and produce a flash of light.

A flash-bulb contains oxygen, so that the wire or foil burns with a very bright light. The light is slightly yellow and this is why flash-bulbs for daylight colour film are blue. The blue container changes the colour of the flash to the white colour of sunlight.

HOW ARE COLOUR SLIDES MADES?

A colour film has three layers that take yellow, red and blue pictures of a scene. A colour slide or print contains three layers that are yellow, red and blue. When you look at a colour print or slide, these three colours combine in various ways to give a full-colour picture.

The three layers are sensitive to different colours in the light. The film also contains a transparent yellow band which helps to separate the colours in the light. When the slide is viewed, white light passes through it to the eyes. The yellow, red and blue images combine to give a full-colour picture,

HOW DOES A MOVIE CAMERA WORK?

A movie camera has a film like an A ordinary camera. But instead of taking just one picture at a time, it takes many pictures every second. As the film moves past the lens in the camera, a shutter continually opens and closes to give a long line of pictures on the film. Then the film is developed and shown on a screen.

Many movie cameras take a cassette of film. The cassette contains a long strip of film that lasts several minutes. It has an opening through which the film passes into the film gate. A claw mechanism pulls on the sprocket holes in the film to advance it frame by frame.

HOW ARE CARTOON FILMS MADE?

In a cartoon film, drawings seem to move. In fact you are seeing 24 different drawings every second, which gives the illusion of movement.

Each of the drawings is photographed separately with a special movie camera, Each frame of the cartoon is photographed on an animation stand. The drawing is placed on a table and the camera is mounted on a frame above. So that artists need not paint the whole of every frame, parts of the picture are painted on separate transparent sheets. Then these are placed on top of a background illustration to build up each frame.

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