Fun with Science – The Cause of the Camera!

Can you imagine the world today without a camera?

No pictures, no videos and no selfies! Can’t say we would enjoy being in such a world, can we? But do you know, how did the camera came to be about? What is the principle behind a camera?

It all works with the magical world of lens, light and focus. Today, we take you through an activity which tells you how  an entire scene unfolds in front of your eyes and gets small enough to be captured in a photograph. The only limitation is that your handmade model cannot capture and memorize the photo. You can call it a live camera!

You will need

  • A magnifying lens salvaged from a magnifying glass (also available at stationery stores)
  • Wax paper
  • A cardboard
  • Glue
  • Cellophane Tape

How to Make

The distance where the lens gives the sharpest image is the focal length of the lens. Measure the focal length of your lens by holding it against a window and projecting the image of outside trees/building/sky etc on a paper by holding it on the opposite wall.  Measure this length. Let’s call it x.

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  1. Cut the cardboard into five square pieces whose sides measure the same as the focal length of the lens, i.e. x.

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2. Take four of these cardboard pieces and stick them using a tape making a cube shaped box with four sides.

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3. Take the fifth square cardboard piece and make a neat circular hole in the center of the cardboard, slightly lesser in size than the diameter of the lens.

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4. Tape the lens on the circular hole.

 

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5. Tape the cardboard piece with lens to any of the open ends of the cubicle tube and seal the edges of the all cardboard walls properly.

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6. Cut a wax paper and stick it to the other open end of the cube. Make sure that the paper is taut and firm, with no wrinkles on it.

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7. Your camera is ready! Point the lens to a bright landscape (preferably sunlit) and enjoy the upside-down image on the wax paper.

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Why is the image inverted?

To form an image, light has to bounce off an object, travel towards the lens, and continue on to the back of the camera where the image is formed. Also, we need to remember that light always travels in straight lines.

When we see the tree in front of us, and we attempt to capture it, the light bounces off the top of the tree towards the lens. Similarly, there is another ray of light that bounces off the base of the tree towards the lens. This now forms a triangle. Now, the light will continue to travel inside the camera to the wax paper. If you extend the imaginary line in which the light traveled from the top of the tree to the lens, you will find that it ends at the bottom of the wax paper. In the same way, continuing the line from the base of the tree would end up at the top of the wax paper. In other words, all the light rays are inverted from where they started out. An upside-down view from out of the window on your wax paper!

In the old days, the cameras simply displayed the inverted image. Later on, they came up with a method using prisms to flip the image over inside the camera so it would display right side up. And electronic cameras flip the image electronically for you. But whatever the kind of camera, the same basic principles of optics apply.

Get this experiment with some add-ons in form of a kit right now! Click Here!

Editor’s Note:

Meet Bhagyesh and team at the Hyderabad Kids Fair (June 2-5 2017) at Hitex, and do some amazing experiments with them at the FREE Science Workshop !

 

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