DIY Microscopes
Activity by Claire Bomkamp, UBC volunteer
Adapted from: http://www.instructables.com/id/10-Smartphone-to-digital-microscopeconversion/
For each microscope:
• Stack of books (~3" tall)
• Small books/magazines for height adjustment
• Slide or piece of plexiglass
• Tape
• Hairpin
• Laser pointer lens
• Light source
• Smartphone or tablet with camera
Remove the lens from the laser pointer (do this ahead of time): This may be more or less
difficult depending on the brand of laser pointer you choose. There are instructions available
here:
http://www.instructables.com/id/10-Smartphone-to-digital-microscope-conversion/
but this method may not work for some brands. In this case, take off the front of the laser
pointer and use a knife or razor blade to saw off the black plastic piece at the base. The lens
is inside of this; it may take some extra work to remove the plastic from the lens itself. The 2in-1 laser pointers from the dollar store at Broadway & Blenheim are good since you can use
the extra light for your light source. The lenses are slightly hard to get out though.
Set up the microscope (you can have the students do this themselves): Hold the lens
between the two prongs of a bobby pin (it’s easier if the lens sits inside one of the “bumps”).
Tape the bobby pin to the phone/ tablet so that the lens sits directly in front of the camera
(see the instructables page for picture). If the phone/tablet has a case you will probably want
to remove it. Test whether the setup works by holding the camera ~1cm from a coin or a
piece of paper with text on it. Move the phone/ tablet up and down slowly, and the thing you
are looking at should come into focus. If not, try flipping the lens around - it may or may not be
symmetrical (the ones in the kit work either way).
For backlit specimens: Set a textbook or stack of books (3 inches high at least; hardcover is
best) on a table. Set your slide on top of the book so that ~1 inch hangs off of the edge. Place
a ~0.5-1cm stack of small books/ magazines on top of the slide, and set the phone/ tablet on
top of this so that the camera is directly above the slide. Place your light source directly below
the slide. You can either tape it to the table or have someone hold it. You may need to adjust
the height of the camera with respect to the slide to get your specimen in focus by adding
extra layers of paper. I find it helpful to have it adjusted slightly higher so that you can put light
pressure on the phone/ tablet using your hand to adjust the focus as you look.
For side lighting: Place the specimen on the table and prop the camera above it using
magazines. Put the light next to the specimen and adjust as needed. Having a dark
background can help for viewing some specimens (such as water bears).
Supplies for collecting and preparing samples:
• Cups
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•
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Food coloring
Vinegar
Isopropanol
Transfer pipettes
toothpicks
petri dishes
Prepared slides
Samples to bring:
• Onion (cut up ahead of time)
• Pond water
• Seawater
• Moss/ lichen (soak ahead of time, see below for details)
• Prepared slides from LTS supply room
You can take the students outside to collect their own samples, and/or ask the teacher to let
them know in advance that they can bring in things from home.
Onion skin is a good first sample to look at since it’s easy to see individual cells and the
students can see how the microscope works before going to collect their own samples. Peel
off the thin membrane that separates the layers (you will not be able to see individual cells
with a thicker section). Place a piece on your slide and add a small drop of water or food
coloring/ stain. You should be able to see fairly well using no stain, but adding a bit of food
coloring diluted with water (1:10 or so) can help to differentiate the cell walls a bit more
clearly. You will be able to see individual cells under the microscope, and if you zoom in you
can sometimes make out the nucleus as well. Moving the light around will change how well
you can see the cells; in my experience the best position is below the slide but slightly off to
the side.
Tips for finding water bears: http://tardigrade.us/how-to-articles/how-to-find-tardigrades/
Questions:
How is this microscope different from one you would find in a lab? It can't make things as big,
it's harder to focus, it's way cheaper, etc. But the way it works is basically the same!
What can you see under the microscope? Cells, possibly nuclei, larger structures.
Can you see atoms and molecules under the microscope? No, those are way too small!
Proteins are big compared to most other molecules and they're still much too small (there are
exceptions such as certain polymers, can talk about this if you have time).
For older groups or if you have discussed light: If we had a better lens could we see atoms
and molecules? No, limited by wavelength of light. You can also discuss EM (also limited by
wavelength but you can still go quite a bit smaller than with light) and AFM.