(Remember that to teach true science, you must teach the art of exploration and discovery, and how to be creative. You might not have the piece of expensive equipment needed to do the job at the professional level, but you can "invent" something that may work good enough for you to explore or scout ahead enough to know if you are on the right track. Hence, in the following is a bit of play-acting.)
If you need thin slices of living or raw material, you would want a microtome in a freezer (cryostat). Tell the students about how it works. Then wish aloud that you had such a device. Move on to something else for a few minutes. THEN turn the light bulb on and yell: "I have it! For a crude microtome, we could use a nut and bolt. Let me look around in my desk drawer - maybe I have one amongst the junk in there. By golly, I have one! Let's see if we can make it work." You are giving them one of the most important lessons they can get as Homo sapiens - the tool user: how to be a tool maker. (And you can mutter about such things as you put things together - an inserted anthropology lesson!)
You need a rather large nut and bolt (3/8 inch diameter or larger; length is hardly relevant). And the nut must have at least one smooth side because across it you/they will slide a razor blade. Strong suggestion: use brass nuts and bolts: (a) don't rust, and (b) won't dull the razor blade.
- screw the bolt about halfway into the nut.
- heat the nut a little and put a drop of wax into the "cup" on the other side of the nut from where the bolt went in.
- cool to the point that the wax is mushy
- immediately stuff a bit of whatever it is into the cup and let the wax cool and set.
- lay the "apparatus" down onto the table top so that a side of the nut is flush on the table, and the head of the bolt is also touching the table. It would be good if you had a bolt with a hexagonal head so its flat side can lie on the table.
- Pressing the apparatus tightly down onto the table to prevent any rotations of thepart, use the surface of the nut as a guide, and slice off the protruding part of the lump of plant matter.
- turn the bolt clockwise into the nut so that its next face lies flush with the table, and slice again. If slice is too thin, rotate bolt two faces and slice again.
- Once you get slices of the right thickness, always rotate the appropriate number of faces.
- Immediately place the slices in water to prevent their rapidly drying out.
- Once you have enough slices, you must then worry about how to mount them on the slides.
