SCIENCE FROM JUNK - OPTICS EXPERIMENT

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MAKE A PINHOLE CAMERA

This is an exciting working science model which can be built with household materials and will give you countless hours of fun showing it to kids or friends! 

Do you know how does a camera change a big scene into a small picture? You can see this yourself by making a pinhole "camera."

YOU WILL NEED:
Shoe-box
Wax paper or piece of white plastic cut from a shopping bag

INSTRUCTIONS:
1. Punch a hole in the center of the short side wall by pushing a pencil through it.
2. On the opposite side from the hole, create a rectangular opening.
3. Fix the piece of plastic sheet or wax paper to this opening using a stapler.
4. Close the shoe-box.

Your pinhole camera is complete!

Hold the camera at arm's length, with the waxed paper/sheet toward you. Point the camera at the bright object. On the surface of the waxed paper/sheet, you will see a picture of the object—backward and upside down.





SCIENCE BEHIND:

Each point in the scene emits light, and, just like the flashlight, the beam of light from that point passes through the pinhole and creates a point of light on the plastic sheet. All of the points in the scene do that at the same time, so an entire image, in focus, is created on the back wall of the room. The image is very dim because the pinhole is so small, but you can see it if the room is very dark.

A real camera uses the same principle as your pinhole camera. 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 image is brighter.

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