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Journal of Biological Education
ISSN: 0021-9266 (Print) 2157-6009 (Online) Journal homepage: https://www.tandfonline.com/loi/rjbe20
Applications of microscopy in science education:
gifted youth, public school, and the next-
generation science standards (NGSS)
Joel I. Cohen
To cite this article: Joel I. Cohen (2020): Applications of microscopy in science education: gifted
youth, public school, and the next-generation science standards (NGSS), Journal of Biological
Education, DOI: 10.1080/00219266.2020.1720772
To link to this article: https://doi.org/10.1080/00219266.2020.1720772
Published online: 28 Jan 2020.
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Applications of microscopy in science education: gifted youth,
public school, and the next-generation science standards (NGSS)
Joel I. Cohen
T. W. Pyle Middle School, Montgomery County Public Schools Maryland (MCPSMD), Bethesda, MD, USA
ABSTRACT
Microscopy is not specifically mentioned in the Next Generation Science
Standards (NGSS), and consequently secondary education limits its use to
learning parts, procedures, and observing fixed specimen slides. However,
when alternative approaches (See Section IV in this paper) are encour-
aged, microscopy provides opportunities for hands-on learning, engage-
ment, use of models, and gaining a sense of size, scale, and hierarchical
organisation. This article reviews living organism- and ecosystem-based
microscopy originally designed for gifted and talented education, and
how it could support the NGSS Life Science Framework. The paper begins
with a review of curriculum, then discusses (1) five ongoing microscope
applications relevant to the NGSS, including mini-ponds modelling eco-
system-organism functions; (2) data from pre- and post-testing as
a measure of comprehensive learning; and, (3) a culminating communica-
tion project/exhibit on pond life, environmental conditions, and pollution
effects.
KEYWORDS
Gifted and talented; biology
education; protists;
pollution; secondary
education; NGSS; Microscopy
Computer science is no more about computers than astronomy is about telescopes, biology is about micro-
scopes or chemistry is about beakers and test tubes. Science is not about tools. It is about how we use them, and
what we find out when we do. –Dijkstra (2000)
Introduction
Biology teachers face numerous obstacles when introducing lessons dependent on the use of living
specimens in the classroom. By adopting such approaches, teachers comply with the mounting
pressures and constraints imposed on their curriculum (Wright and Boggs 2002), including the
time needed to meet state educational standards. For these reasons, many secondary and under-
graduate courses rely on dry mount specimen slides to teach introductory microscopy, with
students limited to basic observations and learning only basic operations.
This article follows one describing a cellular encounter (Cohen 2014) as one means to expand
principles of the NGSS while further challenging students in their education. Each paper provides
the means to work in ‘extenders’and accelerated activity while still covering the basics.
This paper contrasts experiences with teaching microscopy in two settings: (1) over 10 years of
teaching public-school seventh-grade biology classes, and (2) 7 years teaching a three-week summer
course for gifted and talented students. Over this time, the secondary course adopted standards,
homogenised lessons, common tasks and end-of-quarter assignments (MDE 2011;https://www.
montgomeryschoolsmd.org/curriculum/science/). The microscope’s use was limited to its opera-
tion, one procedural assessment, and viewing of fixed specimen slides to distinguish between uni
CONTACT Joel I. Cohen cohenji@comcast.net
JOURNAL OF BIOLOGICAL EDUCATION
https://doi.org/10.1080/00219266.2020.1720772
© 2020 Royal Society of Biology
and multicellular life. Elodea was the only live specimen used for viewing chloroplasts and a house
plant for viewing stomata, with no further opportunities for discovery or investigation.
While the NGSS are limiting in terms of advancing microscopy to any great degree (NGSS
LeadStates, 2013), other approaches recognise opportunities from expanding its use in biology. For
example, Storksdick (2015) sees using microscopy as a way to further ‘the vision for science
education reform.’He notes that the microscope allows exploration of the unseen, and aids in the
exploration of natural phenomena, facilitating labs that touch on the eight science and engineering
practices identified by NGSS (Table 1).
While states implementing the framework have noted that ‘NGSS focuses much more on doing
science with real-world application as opposed to only memorizing content,’(Fogarty 2016), states
and school systems seem unaware of professional positions for those trained in microscopy.
Scientists have developed new staining techniques and are using microscopes beyond the com-
pound light model. These new approaches can scientifically illustrate and create images used to
diagnose illness by capturing organisms in what appears as an almost artistic format (Lutkoski
2019) so unique that images hang in art galleries.
Microscopes are also used to confirm the presence or absence of specific environmental patho-
gens detected by biofilms. Colonies of bacteria begin to grow on the biofilm strips which must later
be identified. This confirmation of a particular bacterium is made almost exclusively through the
microscope (Henk 2003).
Finally, microscopy jobs are growing and specialising. The box below shows one such position.
Compiling these ads would give students a real-world feel for opportunities that do not require
extensive post-graduate degrees. Thus, competency in microscopy, along with other biological
content, can lead to practical work outcomes.
The Analytical Instrumentation Facility (AIF) at NC State University is seeking an expert staffscientist to lead
its efforts in biological electron microscopy and associated sample preparation techniques. The AIF is
a leading microscopy . . . .
The course developed for John Hopkins Centre for Talented Youth (CTY) has also changed from
previous approaches relying on prepared slides and a final week focusing on DNA to one of
living specimens and objects of a size where compound light microscopes have a comparative
advantage. The course is titled Through the Microscope (SCOP), Session II, and employs the
microscope as a tool to explore, compare and contrast organisms representing the six kingdoms
of life.
The six kingdoms selected are consistent with the three-domain, six-kingdom classification
system that arose after the discoveries of Dr. Carl Woese, Kandler, and Wheelis (1990), regarding
distinctions between what have been termed the Archaea, Bacteria and Eukarya domains. Within
these domains, especially due to the separation of the Archaea from Bacteria, six kingdoms are
used instead of five, as follows: Archaebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia.
This system is now the basis for classification in standard American textbooks (See for example,
Reece et al. 2014; Coolidge-Stoltz et al. 2009). Details of selected course activities are presented
subsequently, along with others available from the author in a companion workbook (Cohen
2019).
Table 1. Eight NGSS science and engineering practices for the classroom.
(1) Asking Questions and Defining Problems
(2) Developing and Using Models
(3) Planning and Carrying Out Investigations.
(4) Analysing and Interpreting Data
(5) Using Mathematics and Computational Thinking.
(6) Constructing Explanations and Designing Solutions
(7) Engaging in Argument from Evidence
(8) Obtaining, evaluating and communicating information.
2J. I. COHEN
Plausible opportunities to support NGSS core ideas through microscopy
Searching the NGSS web site (https://www.nextgenscience.org/standards/standards) for micro-
scopes or microscopy does not reveal any ‘hits.’As already noted by Storksdick (2015), theoretically
though, there seem to be several areas where students could extend their understanding of NGSS
disciplines in conjunction with microscopic laboratories. Table 2 identifies five component ideas of
seeming compatibility and mutual interest with the approaches described in this article. These five
component ideas, out of a total of 14, that have the greatest potential to benefit from the activities
described, when adjusted for age and grade level.
Opportunities for change
Introduction. In this section, ongoing approaches for using microscopy are considered in regard to
NGSS core ideas considered above. Examples benefit from changes made over the time spent
teaching Through the Microscope (SCOP), offered by John Hopkins’Centre for Talented Youth
(CTY). The curricular approaches and activities described were designed by the author, and used in
agreement with the course’s administration provided by CTY staff(https://cty.jhu.edu/summer/
grades2-6/catalog/science.html#scop).
The course is taught over a three-week period, beginning with the fundamentals of scale and
scope, followed by microscope theory, and operational procedures and safety. Special attention is
paid to Antonie van Leeuwenhoek, and his drawings made with ‘the simple microscope,’as they
were ‘so striking, owing to the minuteness of the structures that he dealt with and the accuracy of his
observations,’(Clay and Court 1975). Next, students begin studying living specimen growth and
development of organisms representing each of the kingdoms of life. Student preparation of
mounted slides and a culminating project on freshwater pond life and pollution follow.
This paper presents an analysis of some of these experiences, organisms selected, laboratory
objectives, and their culminating posters and presentations. The course now uses the microscope
to enter a world requiring ‘the close observation of organisms –their origins, their evolution,
Table 2. NGSS core ideas, components and five possible areas of synergy with microscope applications.
NGSS Core Idea Core Idea: Details Component Ideas
Ideas Complementary to
SCOP
LS1: Molecules to
organisms
Structures and processes LS1.A. Structure and function √
LS1B. Growth and development of
organisms
√
LS1.C Matter and energy flow X
LS1.D Information processing X
LS2 Ecosystems Interactions, energy and
dynamics
Interdependent relationships in ecosystems √
Cycles of matter and energy transfer in
ecosystems
X
LS2.C: Ecosystem dynamics, functioning and
resilience
√
LS2.D: Social interactions and Group
Behaviour
X
LS3 Heredity Inheritance and Variation of
Traits
LS3.A: Inheritance of traits X
LS3.B: Variation of traits X
LS4 Biological
Evolution
Unity and Diversity LS4.A: Evidence of common ancestry and
diversity
X
LS4.B: Natural selection X
LS4.C: Adaptation X
LS4.D: Biodiversity and humans √
JOURNALOFBIOLOGICALEDUCATION 3
their behaviour, and their relationships with other species,’(Wilcove and Eisner 2000; Green
2005).
It is intentionally designed to mirror the introduction to shore life provided by Rachel Carson in
her beginning to The Edge of the Sea,‘To understand the life of the shore, it is not enough to pick up
an empty shell and say “This is a murex,”or “That is an angel wing.”True understanding demands
intuitive comprehension of the whole life of the creature that once inhabited this empty shell: how it
survived amid surf and storms, what were its enemies, how it found food and reproduces its kind,
what were its relations to the particular sea world in which it lived,’(Carson 1955).
The course is designed for a class of 12 advanced fifth to fifth graders, but it can be modified to fit
32 as per public secondary school classes, with objectives set to high school standards. The relatively
short-term maintenance of a fresh water pond, stocked with protists and other organisms, can serve
as a model system for studying an organism’s interaction with environmental concerns, including
diminished biodiversity.
Some of the key topics covered by the course curriculum include: understanding structure and
function of the cell and selected organelles; interactions between living organisms and their
environment; key vocabulary words; plant development beginning with seed germination; and
a culminating ‘exhibit’featuring a group-made pond poster. The course incorporates the micro-
scope’s ability to illustrate various concepts necessary for learning and examining material germane
to these topics.
Many of these items would directly support long-term quarterly requests for proposals (RFA),
something now fashionable in conjunction with the NGSS. Success in students grasping complex
content in a short period is demonstrated in numerous ways throughout the course, but for this
paper, cumulative knowledge gained, as measured by the pre/post assessment is used, as seen in
Section V.
The following elements of the SCOP curriculum are a limited sample seemingly relevant to
NGSS component ideas, as shown in Table 2.
Use of protists
‘Aworld in a drop of water.’So thought Anton van Leeuwenhoek, as he observed and drew his tiny
‘animalcules,’(Silverstein and Silverstein 1969) for he was a person in the ‘habit of examining
everything under the sun,’(Grave 1984). Now, these are classified as protists, described as mostly
unicellular, widely divergent organisms with a nucleus. The complexity of their cellular structure,
some found in no other type of organism, is remarkable, being organisms that are neither plant,
animal or fungi. Because of their unique qualities, SCOP students examine a number of protists
each year. They serve as a microcosm of life’s diversity and are excellent when doing compare/
contrast analysis with specimens of the plant and animal kingdoms.
Thus, for this SCOP course, the microscope becomes that tool, when mastered, becomes an
extension of one’s eye into the unknown, harbouring the potential for remarkable sightings, as if to
one having eyes poor of sight following a gift of a pair of glasses. The protists included in the course
are chosen to be representative of nutrition groups, including (a) heterotrophic or animal-like
protists (protozoa) and (b) autotrophic organisms, which are plant-like protists. The final group,
decomposers/parasites, is not included to date.
Laboratory skills relevant to real-world microscopy
Many of the course’sspecimens are aquatic. Students learned to prepare samples from aqueous
media, sorting out the actual specimens from debris in the solution. Protist specimens include
Stentor, Spirogyra, Volvox, Euglena, Paramecium, Diatoms, Protozoa, seaweed, and Amoeba.
Forams (foraminifera) are also included, although only through fixed slides at this time. With all
these Protists available, each day the students anticipated dipping their pipettes and gathering up
4J. I. COHEN
a few drops from the vials of pond water containing individual organisms. They learned that no
matter the label on the vial, other organisms could also dart across their field of view. As their skills
matured, it mattered little whether they found the organism selected for that day’s study or
something entirely different that surprised them. Gradually that worry of finding the ‘right’speci-
men eased and they learned to pursue the names of whatever they found.
New techniques for mounting and slide preparation are available for school settings (see for
example, Dioni 2014). SCOP students became versed in making wet mounts, well mounts, and
permanent slides with fixative. They were confident in their searches for live organisms, bringing
them into their plastic pipettes and then able to find them again under the microscope. They
consulted with me as to whether the specimen would make a suitable permanent slide. Considering
the minute size of these organisms, these were significant accomplishments for their age group.
Students also learn techniques for safely acquiring live organisms, and depositing on slides for
viewing, including the green hydra, another microscopic animal, a creature of Herculean adventure.
To the students, it was a colossal microorganism with tentacles to trap prey and draw it into its
mouth cavity, making it seem all too similar to the nine headed monster that Hercules defeated.
I would open the container holding the live specimens, packaged with algae for food, the hydra
moving around in about 20 ml of water.
The students first viewed them through the stereoscopic dissecting microscope, reaching powers of
10and20X.Thisgavethemanideaofwhattheywereafter,andwheretogohuntingwiththeirpipettes.
After a quick observation, the hunt began, with students watching for them to appear, and then carefully
pulling them up with their pipette, and depositing the drop or two of pond water on the slide.
Beginnings of life and cell formation
While the issue of common ancestry and evolution was only touched in SCOP, an explanation for
common ancestry is prominent in the NGSS. For SCOP, how cellular life began, in terms of
formation of a membrane, and from there, chemical reactions occurring inside the membrane,
could lead to a primordial cell. As such, the formation of a membrane, and the ability to see it from
purely chemical processes was of importance to SCOP, especially as students came to the course
with USB drives to record these primitive membranes (See Figure 1 as an example).
Figure 1. Simple membranes produced from chemical reactions by student with photo taken on digital microscope. Image is
100x.
JOURNALOFBIOLOGICALEDUCATION 5
Creating freshwater ponds
What eventually become mini-ponds begin by adding 2 containers of Carolina Brand Mystery Mix
to 1.5 gallons of spring water in a 10 gallon aquarium. After 1 week of maturation, a second batch of
organisms (Carolina Brand Review Set) was added to the aquarium. By mid-second week, a third
Carolina product was added (Pond Mixture Living) to the aquarium plus .5 gallon spring water. This
total was then divided to form 12 mini-ponds, using 250 ml glass specimen jars filled half way. The
left-over was kept in the aquarium, in case of spills or evaporation. As the ponds matured, new
organisms entered growth and development, all observed by the students as they learned to sample
their ponds.
Organisms sampled include Paramecium, Euglena, Volvox, Hydra, Planaria, Diatoms, various algae,
Daphnia and others as available. Separate samples were kept of tardigrades, Didinium, Cyclops,and
Stentor. Students studied these organisms to understand their means of movement, digestion, growth and
development, and reproduction. This was accomplished by preparation of fresh mount slides viewed
under simple digital microscope where still shots and video clips recorded on USB drives.
By end of 3 weeks, students could successfully move microorganisms from ponds to slides; take
pictures; estimate length or width; and name them correctly. Examples of pictures taken by students
are seen in Figures 2 (cyclops) and 3(tardigrade). Taken together, these outcomes could supple-
ment the limited work done on fixed slide specimens required by Montgomery county curriculum.
Metric scale for microorganisms
The objects and their dimensions in metric scale, as seen in Table 3, are but a few of those used in
SCOP to configure a metric scale. This is constructed on special architect paper, and goes from 0 to
10
23
and a second range from 10° to 10
−20
. Numerous images with their scale are made to place
upon the scale, so that when done there are two parallel lines, one for the range of positive
exponential scientific notation line above for the negative exponents or those objects of decreasing
size. Further details on this available from the author.
Figure 2. The Cyclops female with egg sacs, a member of the Crustacea, representative of the Animal kingdom. 100x. Slide mount
and photo by student.
6J. I. COHEN
Pre and post testing: measuring gain in cumulative knowledge
Over the past 7 years, the required pre- and post-course test has been modified to better elicit
student responses from lower to higher order thinking. In 2019, it had a total point value of 38, and
ranges from microscope procedures, scale of size, and optics, to questions requiring extrapolation as
to use of microscopes and pond organisms. CTY administration requires the collection of before
and after data to evaluate its course, students and instructor. The data from 2012 to 2019 are shown
in Table 4. Results indicate a sizeable increase in breadth and depth of knowledge from beginning to
end of the course.
Figure 3. A water bear, or Tardigrade, showing numerous body functions and carrying eggs in two internal sacks. X100. Student
prepared mount and photograph.
Table 3. Illustrative table showing approach taken for lessons on scope and scale, featuring scientific notation, metric
measurements, and objects to cut and paste.
Object Measured (Metric Units) and Placed on Scale Scientific Notation Size in Metric units
Height: students measure 10° 1.5 x 10° = 1.5 metres
Length: T. rex 10
1
1.2 x 10
1
= 1.5 decametre
Height: Empire State Building 10
2
4.3 x 10
2
metres = 4.3 hectometre
Height: Mt. Everest 10
3
8.8 x 10
3
metres = 8.8 kilometres
Hand: students measure width 10
−1
1.3 x 10
−1
metres = 1.3 decimetres
Finger: students measure length 10
−2
1.2 x 10
−2
metres = 1.2 centimetres
Organ: human heart 10
−2
10 x 10
−2
metres = 10 centimetres
Microorganism: water bear (tardigrade) 10
−3
1.5 x 10
−3
metres =1.5 nanometers
Table 4. Seven years of pre and post-testing data for the 3-week summer course, through the microscope.
Testing Year
# of stu-
dents
# of Points
per test
Pre Test Score:
Class Average
Post test
Score: Class
Average
Average Point
Value Increase
Average
Percentage ‘Post-
test’
Average
Percentage ‘Pre-
test’
2019 12 38 26 34 8 90 67
2018 11 37 17 30 13 81 57
2017 9 37 21 34 13 92 57
2015 13 36 18 26 8 72 50
2014 12 36 18 31 13 86 50
2013 12 34 17 27 10 79 50
2012 12 33 19 28 9 85 58
JOURNALOFBIOLOGICALEDUCATION 7
The test is taken by each of the 12 participating students, with an average age of 9 years old, an
average of seven boys and five girls, each student having scored above grade level on tests
administered by John Hopkins before admittance.
Summary
Over the 7 years of available data, the average of all pre-test scores was 56%, followed 3 weeks later
with the post-test, having an average of 84%. This is a 28% increase by end of the course. In 3 weeks,
students have helped create a ‘community’in the lab and focus on each topic, given the extra time
and resources available. The final example of student work, as mentioned in the abstract, comes
from the presentation and construction of three freshwater pond posters.
While the trends in the pre/post data are evident, gains could be attributed to other factors
besides the interventions mentioned. To ensure a fair evaluation, the same test was used in both
instances. However, in an attempt to enhance validity, the pre-test was given in the second hour of
the first day and students did not see the test again until the next to last day of the course. For the
sake of comparison, one might compare scores from Session I, having a totally different curriculum,
as compared to the curriculum and data described here. However, one teacher would not have
access to data evaluating another teacher.
Culminating pond poster: obtaining, evaluating and communicating information
As their technical skills matured, I focused on my second objective –to teach comprehensively,
especially for the Protists, allowing them, as Rachel Carson had suggested, to understand their place
Figure 4. One section of Pond Poster emphasising tardigrade, planaria, and effects of human pollution.
8J. I. COHEN
in life, not just on a glass slide, but in their natural habitat –what is it like to be a paramecium, how
did they move, and who chased after them as food. To do this, we made a pond in the classroom,
their natural habitat, and regularly sampled from it. In so doing, their original focus on microscopic
life reached back out to what the macroscopic.
It is easy to overlook these predator–prey relationships, as traditional microscope instruction is
about structure and function. We don’t ask what it eats, or what it is eaten by. However, to
understand an organism’s place in an ecosystem, such as a pond, this is exactly what was needed.
An example of one of the ponds is shown in Figures 4 and 5, each one emphasising the placement of
two organisms and the effect of pollution on their life cycle.
As their knowledge grew, we worked on group projects, where students adopted an organism,
sought out its niche and role in the pond ecosystem, and how its structure helped ensure its survival.
We spent time in the computer lab, with books, and to observe their slides and look again for live
specimens of their organism. Soon, it was time to talk to the class about what they had learned.
Figure 5. Second section of Pond Poster emphasising the paramecium and hydra, and effects of human pollution.
JOURNALOFBIOLOGICALEDUCATION 9
Acknowledgments
The author wishes to express his appreciation to many individuals at John Hopkins CTY, who have carefully
monitored and evaluated the annual changes made in the SCOP course, allowing it to reach its present
format. Second, numerous technical specialists at Carolina Biological Supplies have provided invaluable help and
insight on many of the products used, which have made the course and organisms what it is today.
Disclosure statement
No potential conflict of interest was reported by the author.
ORCID
Joel I. Cohen http://orcid.org/0000-0002-2390-5983
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