You’ve bought your kid a stereo microscope as a birthday present and now wonder what to look at. Or maybe you are teacher and want to give your class an introduction into (stereo) microscopy and need some specimens to look at (or maybe you bought yourself one, and now want to start out observing…)
Requirements of the specimen
When microscoping with children, I recomend the
- Not too abstract: The specimen should not be too abstract for the children. I mean, YOU may be interested in the circuitry of computer electronics parts under the microscope (and they DO look interesting), but for kids I’d suggest something more tangible.
- Flat: A flat object makes it easier to adjust the depth of field. Most of the object will then be in focus.
- Contrast: A high contrast makes it easier to see structures and details.
Specimens to look at
- Safe: This is self-explanatory. Do not use organisms or substances that are hazardous.
- Rocks: Collect some smooth rocks, wash and clean them in running water. Either observe the rocks while they are wet (and still shiny) or make them shiny by polishing them with a drop of oil. Shiny rocks have more contrast and simply look better than dull ones.
- Leaves: They are flat and transparent. They can be observed both with the light source from the top and from the bottom.
- Insects: This can be problematic. The insects should be dead, otherwise they are too difficult to observe, moving around all the time. Be aware that catching insects (such as butterflies) may not be allowed, as some of them are protected.
- Foods: Cornflakes, cut open fruits, seeds, mushrooms can make very educational samples. Place the cut surface is horizontally under the stereo microscope, and you won’t have a depth of field problem.
- Money: Count the scratches on the coins! The highly reflective surface of the coins make them an easy specimen.
- Pictures: This is the first specimen that we use in school when teaching the students how to use the stereo microscope. Printed pictures are made of many dots, which can be observed. Many kids did not know this. This way the children learn how to focus properly and how to change magnification. Later we give them specimens with a thickness.
- Own fingers: Here it is important to instuct the children to rest their fingers on the platform of the microscope. Many children will attempt to view their fingers by holding them mid-air beneath the objective. It is nearly impossible to find a proper focus this way.
- Own handwriting: This is a good possibility to estimate size and magnification.
- Textiles: stretch them flat and observe how they look different in epi- and trans- illumination.
Specimens not to look at
- Dust: some kids may have a dust allergy (mites), but it depends on the type of dust.
- Body fluids (blood): for hygienic reasons. And they are not interesting anyway at a low magnification.
- Spoiled food: fungal spores are not healthy to breath in, and bacteria on food are not good…
- Anything else which can be considered dangerous