Sight is perceived as the most reliable confirmation about the nature of an object (See Vision in Science). Additionally, in order to differentiate the human as more advanced than the other animals with whom we share the evolution of the eye, humans seek to improve upon our capacity for sight (See Externalization of Vision). These two factors place an emphasis on improving visualization and imagery in science which is manifested in ongoing research into the development of new techniques in microscopy and the imaging of outer space. New instruments of visualization increase the certainty of scientific facts. Science is constantly aiming to increase its imaging capabilities on the macro and micro scales, and in turn has produced a wide variety of different techniques for visualizing objects of different scales. When considered in the context of more recently developed microscopy techniques, the utility of the magnifying glass in biological research is limited. Nonetheless, the persistence of the magnifying glass, and of microscope and telescope designs with lower resolving powers than the most up to date versions, indicates that there are many contexts for visualization techniques that propagate the use of technologies like the magnifying glass.
The manner in which new technologies develop is addressed by Leroi-Gourhan in his work 'Gesture and Speech: “the origin of form lies in the pursuit of ideal function; at the same time, however, we have seen that approximation to functional perfection is the rule in all but exceptional cases. The reasons for this are to be found in two opposing trends. The former lies outside aesthetics and pertains to the ‘favorable environment’ theory…: Neither the material…nor the technique…available to…man enabled him to make a perfect tool…Efficient forms are therefore subject to diversity in time and space which is related to the stage of development of the technique concerned.” This trend can be observed in both the development of the telescope, an increase in the scale of observational science, and in the development of the microscope.
Observation of the skies using refraction has been done since the time of Galileo, who observed the Medici stars in the sky in 1609. As telescopes developed, Galileo’s design was replaced by the design of Johannes Kepler, which enabled visualization of a larger area in space. However, in order to produce a quality image, the light rays must be focused at the same point; this required large increases in the length of telescopes, a flaw which decreased the practicality of Kepler’s design. New lens crafting techniques developed in the early 1800s produced lenses with increased size and degree of precision which increased the capabilities of telescopes. By the 1890s, although the size limitations of lens production were overcome, physical limitations of the materials used prevented telescopes from further increasing their capabilities. Instead, the capabilities of the reflecting telescope, which utilizes a mirror, began to be explored. Reflective telescopes continue to be used today, but in order to increase their precision they are being launched into orbit around earth instead of remaining within the atmosphere. New telescopes image infrared light, which allows visualization of objects normally invisible if they are too dim or blocked by dust (1).
The development of telescopes exemplifies the trend in science to increase the scope and capabilities of visualization techniques. Astronomers throughout history have developed ways to increase their imaging capabilities through creative employment of optics and materials available. It is apparent that there is an emphasis in astronomy on increasing the capability of telescopes to image objects on a large scale.
Under the Microscope: A brief history of microscopy states that “the smallest distance we can resolve with our eyes is about 0.1 to 0.2 mm. This is the resolving power of our eyes so any instrument that can exceed that is a microscope” (Croft 58). As resolution of microscopy techniques increases, a rhetoric was created surrounding this decrease in scale. In addition to the centimeter and millimeter, the micrometer or micron was developed, the nanometer, and the Ångstrom (listed in order of decreasing size). To put these in perspective, a human hair has a diameter of about 200 microns and the thickness of a piece of paper is equivalent to 1 million Ångstroms.
On the micro scale, biologists also work to increase the imaging capabilities they possess. Optical microscopy techniques, which utilize multiple lenses and the properties of light, cannot resolve any specimen smaller than 0.2 micrometer due to limitations imposed by the properties of light and optics. Nonetheless, there are techniques to examine specimens of about 2000 Ångstrom, which involve changing the light source in order to resolve specimens of this size. In order to obtain a higher resolution of less than 10 Ångstroms in size, use of an electron beam to image a specimen, called electron microscopy, is used. Its magnification capabilities from 1000 to 250,000 times the size of the specimen allows for high resolution details of cell structure. Directions for microscopy include infrared microscopy, which utilizes energy of a different wavelength and in some cases is able to overcome limitations of optical microscopy.
There is a trend towards increasing imaging capabilities in science, whether it is on the micro or macro scale. These technologies "evolve...to give us a degree of efficacy which overall is increasing,” a trend readily observable in the increased magnification properties of microscopy technologies (Leroi-Gourhan 279). These varying degrees of resolution are useful in many contexts; whereas the compound light microscope, an optical tool, is widespread in biology classrooms, electron microscopy can be used to create high resolution images of cells, and others to create 3D images. Simple reflective telescopes are in household use, whereas the most complex technologies are used in astronomy laboratories and by the National Aeronautics and Space Administration. Although the utility of the magnifying glass as an extension of vision in biological research is limited, its resolution capabilities are sufficient and often preferable for many uses outside of the biology laboratory.
Back to The Microscope versus the Magnifying Glass.
(1) http://amazing-space.stsci.edu/resources/explorations/groundup/
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