Hunting Down the Hay Bacillus – Educational Microscopes in Biology Teaching


Learning begins with perception. Sensory impressions are branded in our mind and become the building blocks of knowledge. The more intensively young people are involved in the lesson and the more experiences they can make themselves, the easier they find it to learn. Hands-on microscopy is therefore a key component of modern science teaching, for example at the Philippinum Grammar School in Weilburg, where students love working with Leica educational microscopes.

"I guess there’s something moving in here." This sentence is often heard in Grade 7 of the Philippinum Grammar School. Whether a hay infusion or waterweed: the 15 students subject each plant cell and organism to close scrutiny under the educational microscopes from Leica Microsystems – and make amazing discoveries.

Searching for unicellular organisms in a hay infusion

Before the hands-on microscopy session begins, the biology teacher Hélène Theobald recaps the key facts on microscopes and microscopy with her class: How do I prepare my specimen properly, how do I get a sharply focused image, what’s an “objective nosepiece”? To start with, they all examine a small waterweed leaf, a so-called tape grass that roots at the bottom of lakes, ponds and other stagnant or slow-flowing waters. The students are then asked to inspect a small sample of the hay infusion under the microscope. Ms. Theobald has already prepared the mixture of pond water and hay three days before, and since then quite a few life forms have developed in it. Numerous small single-cell organisms, such as the hay bacillus or paramecia, are swimming around undetected in the murky yellow liquid.

“That’s really hard to identify“

Without hesitating, they all set about preparing their specimen slides. One single waterweed leaf is enough to begin with. Under the microscope the students can see the cell structure of the leaves. The results are immediately saved and documented, just like in a proper laboratory. Looking for unicellular organisms in the hay infusion turns out to be somewhat more of a challenge, though. "I don’t really know what I’m seeing here. It’s not easy to identify," says one of the children with a skeptical look through the eyepieces. "The single-cell organisms all look the same to me. They’re all round and have little hairs." On top of this, the children have to work swiftly, because the organisms dart to and fro to escape the illumination of the microscope. They still find what they’ve been looking for, however: the hay bacillus – or at any rate something that looks like the hay bacillus.

“You see things you can’t see with your eyes alone.”

The children are fascinated by what they can see through the microscope. "The waterweed is really beautiful under the microscope. The individual cells are arranged in rows and little white dots and lines. You don’t see that normally," enthuses 12-year-old Marlene. Max (13) is impressed, too: "The exciting thing is that it’s so close up. It’s simply awesome to see how the cell is built." Emily (13) is particularly pleased by the fact that she can obtain a result herself. "It’s not like just copying something from the blackboard. I like the way you can do something yourself and try things out," she says.

Working like a real scientist

And that is one of the aims of this hands-on biology lesson. "We want to show the children how scientists work and how they get their results. Microscopy work is part of the process, and an extremely important haptic experience," the biology teacher Hélène Theobald explains. One of the reasons why microscopy is so much fun is the quality of the microscopes. "With Leica microscopes it’s easy to get a really good image fast," Theobald says. "The children don’t have to do a lot of searching and don’t need much help even though they’re beginners. For me, that’s the proof of a good microscope." The children share her opinion. "The microscope is easy to set, it’s easy to get an image and then you’re ready to start," says Moritz (13). "I have the feeling that the Leica microscopes produce sharper images than the others," Marlene says. "I guess the old microscopes were heavier to carry, too."

At the end of the lesson, all the students are satisfied with their microscopic discoveries. Some of them have seen the hay bacillus, others have seen algae, Amoeba proteus, flagellates or colpidium. Their appetite has now been whetted for future lessons. "I’d like to look at an animal hair," says Max. Emily wants to examine even more living organisms, while Marlene is keen to have a look at petals. Moritz is keen to inspect blood or an animal cell under the microscope.  They may still have the opportunity to do some of these things, as microscopy is on the curriculum in the ninth and eleventh grade, too.

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