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You will need: Small cardboard box, ruler, pencil, scissors, razor blade, compass, gummed paper, greaseproof paper or tracing paper, candle.
SCIENCE EXPERIMENTS & AMUSEMENTS FOR CHILDREN BY CHARLES VIVIAN.
Simple Technical Steped Practical Projects for school and college students.
Make a Pinhole Camera
You will need: Small cardboard box, ruler, pencil, scissors, razor
blade, compass, gummed paper, greaseproof paper or tracing paper, candle.
Here is an interesting experiment which will give endless fun. You need a small cardboard box for the body of your camera. Choose one with a nice, deep lid.
First, hold both the box and the lid up to a bright light, as in Fig, 1. Mark any places where you can see even a pinpoint of light.
The box used here had battered corners and these allowed a considerable amount of light to leak through. All these weak points were covered with brown gummed paper (Fig. 2) until no more light could be seen through them.
When satisfied that your box is completely lightproof, draw two diagonals to find the center point of the lid. Use a compass to make a clean hole through the center point, as shown in Fig. 3.
A rectangular hole (aperture), measuring about 2.5-inches by 1.5- inches must now be cut from the bottom of the box. Mark the best position in the center of the box, and then carefully remove the piece of cardboard, with the aid of ruler and razor blade (Fig. 4).
Now place a screen of fine greaseproof paper over the 'window' in the bottom of the box. Use the finest tracing paper or greaseproof paper that you can obtain, as this will provide the best results. Secure the screen with strips of gummed paper, as in Fig. 5.
Your pinhole camera is now complete. Slip the lid into position on the box.
Place a lighted candle a few inches away from the front of the camera, in a darkened room. An image of the candle will appear in an inverted position on the greaseproof screen. By sliding the box in or out of the lid this image can be made larger or smaller.
Aim the camera at the
electric light in a room and an inverted image of this will appear on the
screen. Focus the camera on the window of your room on a sunny day and the
window will appear on your screen -but it will appear upside down.
The reason for this
reversal of image is shown in Fig. 7. The rays of light carrying the picture of
the subject through the pinhole to the screen travel in straight lines.
This camera, of course, has no film and will not
give you any prints.
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