Nektarios Tsagliotis explains how to build an effective microscope using simple materials – enabling your students to discover a hidden world, just as Robert Hooke did in 1665.
Hooke (2009), painted for
The Open University, UK.
Among the items in front of
him are his book,
Micrographia, and a
microscope
Image courtesy of Rita Greer;
image source: Wikimedia
Commons
Like the telescope, the microscope was made famous by the achievements of one of its earliest users. When we consider the telescope in history, we think of Galileo Galilei (1564–1642) and his pioneering observations of the Moon and planets. Similarly, the English scientist Robert Hooke (1635–1703) was one of the first to realise the potential of the microscope. In his book Micrographia, published in 1665, Hooke astonished the public with a fantastical world, where everyday objects such as needles and hairs, ants and spiders, were transformed by magnification.
Hooke’s Micrographia
Image courtesy of the Project
Gutenberg
From a very early age, Robert Hooke’s curious mind drew him into many scientific fields (for this reason he has been called the ‘Leonardo of England’). In 1662, he was hired by England’s recently founded academy of science, The Royal Society, to carry out studies with the microscope. Three years later, he published these and many of his other studies in Micrographia.
This huge book is filled with descriptions of what Hooke saw under the microscope. He claimed that his goal was to use ‘a sincere hand, and a faithful eye, to examine, and record the things themselves as they appear’. Along with descriptions, Hooke included stunningly detailed drawings of the objects he viewed. His lively drawings of insects made them seem, as he remarked, ‘as if they were lions or elephants seen with the naked eye’. The book was a great success and is still considered a masterpiece of scientific literature.
Micrographia was the inspiration for my classroom project, which had two aims. First, to build a working microscope inspired by early models from inexpensive, easily obtainable modern materials that students could use in class; and second, for the students to investigate the microscopic world for themselves, taking Robert Hooke’s studies as a starting point and producing their own observations in the form of sketches and descriptions.
The microscope I built with my students is a modified version of one described by researchers at the Museo Galileo in Florence, Italyw1. It is similar in construction to those used by Hooke and other scientists during the late 16th and early 17th centuries and has the same essential elements: two lenses (objective and eyepiece), a microscope tube, and a diaphragm to reduce optical distortion. The modern materials we used include plastic lenses, each of which was extracted from a single-use disposable camera.
Image courtesy of Nektarios
Tsagliotis
Once built, the microscope has a magnification of approximately 20 times – quite sufficient to reveal the wonders of the microscopic world as Hooke saw them.
This microscope is durable and portable, and can be assembled quickly once the materials have been collected, cut and glued appropriately (see online videow2). It can be used repeatedly for microscope studies and / or observations, requiring minimal maintenance, such as lens cleaning and battery supply for the spotlight. Moreover, it can be stored easily in the classroom and laboratory, as it occupies a small space.
These are plastic tubes used for electrical home installation, obtainable from hardware stores and / or electrical supplies shops.
If you have a compact digital camera, you can even take photos of your magnified specimens. Hold the camera against the eyepiece lens, keep it steady and you will be surprised at the clarity of the images you produce.
A: The new eyepiece; B: the
field lens, which was the
eyepiece of the original
microscope; C: the objective
lens
To achieve even sharper images, with less distortion, you can build a version with an additional lens (a field lens) between the eyepiece and the objective. For this you need to have used a tube connector rather than a film container for the eyepiece, since the film container’s diameter is too wide to hold the lens. Then all you have to do is add another lens-and-washer unit at the top of the connector: this is the new eyepiece. The eyepiece of the original model (described above) becomes the field lens of the three-lens model.
The idea is for 10- to 14-year-old students to use the microscope in a similar way to Robert Hooke, recreating an authentic scientific method of discovery. The students view an object using the microscope and then produce a detailed sketch and a description. Afterwards, the class discusses their results.
in Hooke’s Micrographia
Image courtesy of the Project
Gutenberg
Tsagliotis
My students were enthusiastic about the activity, making a big effort to work in a ‘scientific’ way, like Hooke. Even those who complained that they could not draw tried hardw7 and attempted to describe the object verbally. The whole project encouraged my students to ‘do science’ themselves, demystifying it in the process: they were using an instrument that they had built themselves using simple materials.
This project is part of the research work undertaken by the Greek group for the ‘History and Philosophy of Science in Science Teaching’ (HIPST) projectw8, funded under the 7th Framework Program, Science in Society-2007-2.2.1.2 – teaching methods.
The author would like to thank the coordinator of the Greek research group of the HIPST project, Fanny Seroglou (associate professor at the Aristotle University of Thessaloniki) for her support on the project.
This website also offers a collection of historical texts about 17thcentury microscopy.
For a photographic account of how to construct our microscope, as well as a more advanced one with three lenses (objective, field lens and eyepiece), click on ‘constructing the microscope’.
Tsagliotis N (2010) Microscope studies in primary science: following the footsteps of R Hooke in Micrographia. In Kalogiannakis, M Stavrou D, Michaelidis P (eds) Proceedings of the 7th International Conference on Hands-on Science. 25-31 July 2010, Rethymno-Crete, pp. 212–221. www.clab.edc.uoc.gr/HSci2010
Vannoni M, Buah-Bassuah PK, Molesini G (2007) Making a microscope with readily available materials. Physics Education 42(4): 385-390. doi: 10.1088/0031-9120/42/4/008