Instructables
Picture of Build a Pinhole Magnifier

When I first learned about this device, it was called a "Pinhole Microscope."  I don't think it has enough magnification to be considered a microscope, so I'm just calling it a magnifier.

Materials:

Clear beverage bottle (a half-liter water bottle in this case)

Dark, opaque plastic piece, large enough to cover the top ot the bottle. (top from a peanut can) Cardboard, like from a cracker box, will also work.

Tools:

Knife, scissors, or both (Okay, I'm using tin snips.  They were easier to find!)
CA cement (Superglue, Crazy Glue or the equivalent)
Pin (not shown)
Sandpaper (not shown)
 
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Step 1: Cut the bottle

Picture of Cut the bottle

Cut the neck off the bottle just below where it starts to widen.  This should give you a section about 1" (25mm) long.  Sand the cut edge smooth, so nobody cuts themselves on it.

Step 2: Cut the disk

Picture of Cut the disk

Cut a circular piece of your opaque material, just large enough to cover the top of the bottle.

Step 3: Glue

Picture of Glue

Glue the material over the top of the bottle.  You may want to roughen the bottle top a bit with the sandpaper first.

Once the glue is dry, poke your pinhole in the center of the opaque material.  Start small, it's a lot easier to make the hole larger than it is to try to make it smaller.

Step 4: Finished


Put the object you wish to view under the magnifier, make sure you've got plenty of light, and look through the pinhole!
rickharris3 years ago
Add a drop of water on top of the pin hole and you will increase the magnification many many times.

Early magnifiers started as pin holes - this allows your eye to focus at a shorter range. And then moved to using small round glass beads as a lens magnifying many 100's of times.

Good project. - try the water.
gerbilboy (author)  rickharris3 years ago
Good idea if a plastic top is used, not so good if somebody tries cardboard. In fact, I now recall a version that used clear plastic wrap stretched over the too of a bottle, held in place with a rubber band, and a drop of water placed on the center of the wrap.
A bit of nail varnish round the hole in the card would solve the water + card problem :-)