Make a Pinhole Camera
How does a camera change a big scene into a small picture? To see for yourself, make a pinhole "camera." Start with an empty cardboard box. A round oatmeal box works well. Punch a hole in the center of the bottom by pushing a pencil through it.
Now place a piece of waxed paper over the open end of the box and hold it there with tape or a rubber band. Your pinhole camera is complete.
Sit in a dim room that has a bright object in it, such as a lamp or a window that lets in daylight. Lay a blanket over your head and the pinhole camera.
Hold the camera at arm's length, with the waxed paper toward you and the punched-out hole sticking out from under the blanket. Point the camera at the bright object. On the surface of the waxed paper, you will see a picture of the object””backward and upside down.
A real camera uses the same principle as your pinhole camera except that a real one does the job better. A real camera holds a piece of film instead of waxed paper. That film is coated with chemicals that are changed by light. They make the image into a lasting picture.
In a real camera, the lens does the same kind of job as the little hole””it forms a backward, upside-down image. But the lens lets in a lot more light so the film can do its work quickly.
Source: highlightskids.com
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