Pinhole Images

You Need:

   1. 1 room that can be darkened 1 candle
   2. 1 jar lid 1 roll of wax paper
   3. 1 pair of scissors 1 roll of aluminum foil
   4. 4 clothespins (or blocks of wood) 1 pin
   5. 1 box of paper clips (or a stapler) 1 roll of masking tape

Part A

What to Do

1. Make an aluminum foil ‘sandwich’, by cutting a pair of cardboard
frames and clipping or stapling a sheet of foil between them.
2. Make another ‘sandwich’, using wax paper instead of foil.
3. Support the two ‘sandwiches’ with clothespins, so that they stand
straight up, or ‘tack’ the ‘sandwiches’ to blocks of scrap wood,
4. Mount a candle in a jar lid (to catch the drippings).
5. Set the foil sandwich about 15 cm in front of the candle, and the wax
paper sandwich another 15 cm in front of the foil.
6. Use a hatpin to punch a small, clean pinhole in the foil. Punch the
hole at the same level as the top of the candle.
7. Light the candle, and then darken your room. Caution! Do not leave a burning candle unattended!
8. Describe what you see on your wax paper ‘screen’.

Think about it! (And try It!)

1. Is the image of the flame right side up or upside-down?
2. How can you make the image on the screen larger?
3. How can you make the image on the screen smaller?
4. When is the image the same size as the actual flame?
5. What happens to the brightness of the image when you make the image larger?
6. What happens if you punch two pinholes in the foil?

Part B

You can make a pinhole ‘camera’ from a fruit juice can, a jam tin, a coffee can, a shoe box, or any container that can be made light-proof.

What to Do

1. Tape a square of aluminum foil over a small window at the front of the box.
2. Use a hatpin to punch a small hole in the middle of the foil.
3. Make a ‘screen’ the same way as in Figure 1, but make it just big enough to fit inside the box. It is movable.
4. Make a small peephole to permit you to see the image without darkening your room.
5. Put the lid on the box and see what you can see! Aim your camera at a scene outside your window.

Caution! Never look directly at the sun. Doing so can result in permanent damage to your eyes.

This article is brought to you by the Big Little Science Centre
Visit their web site at: http://www.blscs.org/
Contact Gord at (250) 554-2572 or gord@blscs.org

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