Microscopes out of water drops
Bryan Bishop
http://www.rockcastle.org/activities/watermagnifier/watermagnifier.html
http://bizarrelabs.com/micro.htm
"You can easily make a model based on Leeuwenhoek's microscope. A very
simple one is built from only a paperclip. Straighten out the
paperclip with a pair of pliers (small needle nose pliers work best
for this project). Bend a small, complete loop in one end of the clip.
The loop should be about 1/16 inch (1.5mm) across and as round as
possible. Try not to heavily scratch the metal forming the loop. Rub a
little oil or grease on the loop to give it a fine coating. Dip it in
water (preferably distilled) and slowly remove it. A drop of water
should form that will act as a lens. It is not nearly as strong as
Leeuwenhoek's lenses, but it is the same spherical shape, and will
magnify at about 2x or more."
"""
A table top model can also be constructed, which is a little easier to
use for small specimens. Cut a strip of metal about 4 inches by 1 inch
(100mm x 25mm) from a metal food can or from sheet stock about the
same thickness. File the edges if they are jagged or sharp. Place the
metal strip on a piece of wood, and mark the exact center. Drill or
punch a hole app. 1/16-inch (1.5mm) through this center mark. However
you make this hole, keep in mind that it should be as round as
possible, and that it should be clean and free from burs. The metal
should not "pucker" around the hole, which can happen if it is
punched. It is a good idea to polish around the hole with light grit
paper to clean it up. Blow out any dust that remains afterwards.
Bend the ends of the strip down to form a stand. Oil or grease around
the hole as above, and, using a pencil, transfer a drop of water to
the hole so that the drop remains in the hole. Place a small sheet of
window glass on top of two cans, which are set at either end of the
glass. Carefully place the metal strip on the center of the window
glass, being careful not to dislodge the water drop "lens". Prop a
small mirror under the glass so that light is reflected from it and up
through the lens. Place whatever it is you want to examine beneath the
lens (pollen, small insects, grains of salt or sand, etc.). Focus by
gently pressing on the strip.
"""
"Some interesting little lenses made of oil droplets can be seen in
some kinds of soup such as chicken broth. Little drops of oil from
the chicken's fat float on top of the broth. They are more like
lenses than drops of water are, but they are hard to lift and use.
Try cutting a tiny strip of newspaper picture and see if you can slide
it under such a "broth lens" to make the picture dots larger."
Also interesting--
Water-drop projector
http://heybryan.org/books/papers/Water-drop%20projector.pdf
Water droplet lens microscope and microphotographs
http://heybryan.org/books/papers/Water%20droplet%20lens%20microscope%20and%20microphotographs.pdf
Fast focusing using a pinned-contact oscillating liquid lens
http://heybryan.org/books/papers/Fast%20focusing%20using%20a%20pinned-contact%20oscillating%20liquid%20lens.pdf