Few research instruments are as widely used in science as are microscopes. They are very extensively utilized in universities, industries, hospitals, specialized assay services, forensic labs, mineralogy, crystallography, etc. Microscopes and microscopy recently have become more available and more adapted for science education, beginning in primary (elementary, grade) schools. For those of us working with microscopes, they not only let us do our specialized job in scientific research, but also provide quite a lot of fun.
The fundamental concepts and terms for using microscopes and understanding microscopy in general (see: “Part 1” ), and, light microscopy (see: “Part 2” ) and electron microscopy (see: “Part 3” ) in particular, have been covered previously. This fourth article gives my views about the value of microscopy for teaching science in primary and secondary (middle, high) schools. Beginners reading Part 4 should first study Part 1.
Why is microscopy really, really good for early science education?
I believe that early science education is not only essential for future scientists, but also is badly needed for everyone else. I am especially enthusiastic about using microscopy for science education in primary schools, since it: (1) features hands-on learning, (2) is not selective for any one branch of science, (3) involves doing, seeing, thinking, questioning, and discussing, (4) can be open-ended since the young students will utilize their native curiosity to look at additional specimens of their own choice, and (5) raises early interest in some students for becoming a scientist. Addition of hands-on microscopy to primary and secondary school science classes will make them wonderfully better than the traditional science teaching that emphasizes memorizing facts and figures. That old approach neither elicits student enthusiasm and individual interest in science, nor prepares students to live in a modern world that is dominated by new and changing technology. Education with microscopy is education in science and technology.
Microscopy for science education: what will actually be learned?
In addition to learning how to operate light microscopes, young students will relate this to many other areas of knowledge and activity. Coursework with microscopy teaches at 2 distinct levels: direct knowledge, and indirect knowledge. Direct knowledge covers essentials in optics, design and features of different microscopes, specimen preparation, imaging, and measuring. Microscopy in secondary schools should include introductory instruction about electron microscopes, crystallography and diffraction, and, spectroscopy. Indirect knowledge is given when an image from microscopy is shown to illustrate a didactic subject in some other course (e.g., flowers or minerals, disease bacteria or viruses, the human eye, biofilms, LEDs, solid state computer devices, normal and cancer cells, polymers, etc.). Understanding microscopy thus helps students to learn about many other subjects. Specimens selected for classroom use always should include some objects already familiar to students, and, be coordinated with concurrent other courses.
What does microscopy do for science education that books and videos do not do?
For young students in primary school, looking is not enough! They must learn to see (e.g., substructure which is not visible to the naked eye), to think (e.g., why do we not always look at specimens only with the highest magnification lens?), to discuss (e.g., how can the diameter of human hairs best be measured?), and to ask questions. For learning, classes using microscopes have at least 7 major advantages over reading textbooks:
1. microscopy is a hands-on activity;
2. microscopy simultaneously involves activity by the eyes, hands, and brain;
3. “facts” are not learned; instead, how to use visual information, how to operate this optical instrument, and what exists in unseen worlds, are learned;
4. microscopy is very conducive to classroom discussions and Q&A, and is suitable both for individual efforts and group work;
5. optics of microscopes can be extended to also involve binoculars and telescopes;
6. students will learn both about optics and microscopes and about the different specimens being examined and discussed; and,
7. microscopy is fun! Dr.M. and some other scientists even consider microscopes to really be toys, as well as research tools!
One example of a primary school science class using light microscopy.
This laboratory class uses magnifying glasses (see: “Part 2” ) and dissecting light microscopes to examine a paper towel, a sheet of notebook paper, a bird feather, and skin on the human arm. It is preceded by a full introductory class that defines and explains lenses, magnification, resolution, and the basic design of the dissecting light microscope. Students each will study one specimen at a time; between specimens, their teacher engages them with questions and discussion.
In this primary school science class, the students should learn:
1. the practical aspects of what was presented in the preceding introductory class;
2. differences in magnification and resolution for the naked eye, a magnifying glass, and a dissecting light microscope;
3. that not everything which exists can be seen by our own eyes;
4. that papers are made of small fibers compressed together to varying degrees;
5. that flight feathers of birds are complex structures made of regularly spaced fibers attached to a stiff backbone strut; and,
6. that several sizes of hairs are present on normal human skin.
Duration for this lab session can be from 1-3 hours. If needed (e.g., because class time is limited to 45-60 minutes in length), the session described can be enlarged to become 2-3 consecutive sub-sessions; in that case, the specimens can be divided amongst the different periods. Note that everything listed above is done without imaging; if imaging is available, it certainly should be used and additional time will be needed. Ideally, this class can be followed later by another class working with compound light microscopes.
One example of a set of secondary school science classes involving microscopy.
For secondary schools, science classes using microscopy can be more detailed, and will include: (1) more emphasis upon the specific specimens being examined, (2) making actual calibrated measurements with a light microscope, and, (3) discussions and Q&A at a more advanced level. Electron microscopy also should be included (see next section).
This example uses a set of 3 consecutive sessions. The first class will instruct about the general design of a compound light microscope. A second class either will use compound light microscopes, or will watch projected images of one being used by their teacher, with 4 specimens: (1) a piece of a paper towel, (2) a piece of notebook paper, (3) a stained blood smear, and (3) a drop of pond water containing some protozoa. If available, imaging is performed and copies are distributed for each student’s notebook. The third class will be a Q&A session covering measurements of length; this features how images are calibrated for making size measurements, and an introduction to the standardized science scales for length. The first and third sessions will last for one hour each; the second class might require 2 or more hours.
In this secondary school science class, the students should learn:
1. the concepts for magnification, resolution, and practical usage with magnifying glasses, dissecting light microscopes, and compound light microscopes;
2. what can be visualized in a paper towel and a piece of notebook paper with a magnifying glass, dissecting light microscope, and compound light microscope;
3. what differences can be visualized in a stained smear of blood cells with the naked human eye, a dissecting light microscope, and a compound light microscope;
4. what are the standard scales for linear size;
5. how are accurate length measurements of small sizes made with microscopy; and,
6. how small are red blood cells?
Treatment of electron microscopy for science classes in secondary schools.
Only very few secondary schools have an electron microscope in-house. This important aspect of microscopy thus must be taught by showing images and videos, both of which are readily available on the internet (see “Part 3” ). At the very least, secondary school students should learn (1) the basic design of the transmission and scanning electron microscopes, and (2) their operational capabilities; this instruction can be given in one hour. In addition, a second hour-long class will present discussion of the most fundamental differences between light microscopes and electron microscopes:
1. electrons are charged, but photons are uncharged (i.e., they are neutral); thus, electron microscopes use electromagnetic lenses, while light microscopes use glass lenses;
2. electron microscopes have better resolution and give higher useful magnifications than do light microscopes;
3. electron microscopes can visualize individual atoms, unlike light microscopes;
4. light microscopes can image living cells, unlike electron microscopes;
5. light microscopes easily can produce no radiation damage, unlike electron microscopes;
6. light microscopes can examine wet or hydrated specimens much more easily than can electron microscopes; and,
7. electron microscopes cost much more to purchase and operate than do light microscopes.
Lets go beyond the usual classroom teaching!
One very special approach for teaching about electron microscopy in schools is to invite an electron microscopist from a local university or industry to present a gratis illustrated session describing what they do with electron microscopy in their work. For this teaching activity to succeed in secondary schools, the visitor absolutely must: (1) simplify their presentation from the usual very detailed coverage, (2) not use more than a few specialized terms, and (3) leave a good 15 minutes (out of 50-60 total) for student questions about electron microscopy. I know that almost all electron microscopists would be pleased to contribute to local science education of schoolchildren (or adults!) in this way; the Microscopy Society of America provides instructions on “Locating a Microscopist-Volunteer” , which offers helpful advice for finding a suitable presenter.
Resources for science teachers about using microscopy in their classes.
There is an amazing amount of help available! Science teachers need not fear the fact that they have never before operated a microscope, because there are good instructional programs for their learning to do that. These include workshops on “how to do it” for light microscopes. Very much guidance, instruction, and practical help is available on the internet, including articles by teachers about their experiences with using microscopy in a school classroom. For example:
(1) Commercial manufacturers of light and electron microscopes, digital cameras, and microscopy accessories often offer extensive instructional material on their websites.
(2) Some light microscopes now are specifically manufactured for use in school classrooms, and cost much less than any used or new research instrument. Look up “light microscopes for schools” or “teaching light microscopy” in any Web Browser, and you will see prices and descriptions about what is available. For extensive guidance on the essential tasks of selecting what to buy and finding funds for purchasing, see: https://www.microscopy.org/education/projectmicro/buying.cfm .
(3) Some well-designed classes and needed materials for light microscopy are available commercially. These include complete kits with teaching guides and student manuals, raw specimens and prepared slides, and, all needed small equipment.
(4) Useful advice from teachers who already are using microscopy in their science classes is presented on quite a few websites (i.e., search for “Microscopy in the classroom” or “Teaching microscopy in schools”).
(5) “Microscopic Explorations” is a much acclaimed guidebook by GEMS (Great Explorations in Math and Science) that is targeted to Grades 4-8 in primary schools ( http://lhsgems.org/GEMmicro.html ).
Both light and electron microscopy are used extensively in industry and in all 3 branches of science. Microscopes can play a significant role for science education in primary and secondary schools. Use of microscopy in the classroom is distinctive because it: (1) involves eyes, hands, and the brain; (2) emphasizes learning for doing and understanding, rather than just acquiring another bunch of facts; and, (3) is directly related to learning about other topics in science and non-science. Teachers of science should seek to become more aware of what class modules already are available, and of the opportunities that teaching microscopy will provide to elevate the effectiveness of their classes.
Recommended by Dr.M for science teachers: further good internet resources.
1. Several very useful instructional materials for using microscopes in the classroom are offered by the Microscopy Society of America (see “Project MICRO” at: https://www.microscopy.org/education/projectmicro/index.cfm ). This national science society offers over 300 educational DVDs on all aspects of microscopy; some are good for young students in schools (see: https://www.microscopy.org/education/dvdlibrary.pdf ).
2. Hooke College of Applied Sciences and the McCrone Group offer a good description of their programs to instruct science teachers to use light microscopes, so they then can teach this in their classes (see: “Education – Helping Teachers Use Microscopy to Engage Students in Science” ).
3. For a fascinating video story about a graduate student (Mark McClendon) giving presentations on scanning electron microscopy to classes of young students, see: “Beyond the Bench: Bringing Electron Microscopy into the Classroom” by Bethany Hubbard (2014).
4. A good list of microscopy websites is available from the John Innes Centre in the U.K. at: http://www.jic.ac.uk/microscopy/links.html . The Microscopedia web site features applications of microscopy to primary school education, and, includes a variety of news and reports from the world of microscopy (see: http://www.microscopedia.com/Resource/Application/22?ccgid=4 ).
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