Nothing too fancy, a stereo dissecting scope of up to 40x is fine. Even 12X is OK. Zoom is nice, but usally some loss of resolution comes with zoom. Loss of resolution and loss of depth of field also comes with increasing magnification.
Illumination is as important. Although we usually need reflected light (light coming from above the sample), transmitted light (light coming up through the sample) is good for some stuff.
For me, clean lenses, good lighting, depth of field, and high resolution are more important than magnification, within some limits of course. "Depth of field" refers to how much of the 3-D sample is in focus at one time, parallel to the lens.
The classic description of resolution: Picture a long, straight, flat highway. Stand in the middle and look down the road at night. You can see an oncoming pair of headlights from far away, but you see a single light, not a pair. Adequate resolution is when you see that the lights are a pair, not a single lamp. I suppose a "dot per inch" pixel-size analogy might get the point across better. The point is that being able to just see a light in the distance is not as important as being able to discern that there are two lights, not one.
At Huntington Gardens, where the lab session will be, I remember the dissecting scopes as adequate. I expect we will set up a couple of compound microscopes (transmitted light only with slides) with a few things to show the group.
