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Chapter 26 | Vision and Optical Instruments 1167
26 VISION AND OPTICAL INSTRUMENTS
Figure 26.1 A scientist examines minute details on the surface of a disk drive at a magnification of 100,000 times. The image was produced using an electron microscope. (credit: Robert Scoble)
Chapter Outline
26.1. Physics of the Eye 26.2. Vision Correction 26.3. Color and Color Vision 26.4. Microscopes
26.5. Telescopes 26.6. Aberrations
Connection for AP® Courses
Seeing faces and objects we love and cherish—one’s favorite teddy bear, a picture on the wall, or the sun rising over the mountains—is a delight. Intricate images help us understand nature and are invaluable for developing techniques and technologies in order to improve the quality of life. The image of a red blood cell that almost fills the cross-sectional area of a tiny capillary makes us wonder how blood makes it through and does not get stuck. We are able to see bacteria and viruses and understand their structure. It is the knowledge of physics that provides the fundamental understanding and the models required to develop new techniques and instruments. Therefore, physics is called an enabling science—it enables development and advancement in other areas. It is through optics and imaging that physics enables advancement in major areas of biosciences.
This chapter builds an understanding of vision and optical instruments on the idea that waves can transfer energy and momentum without the transfer of matter. In support of Big Idea 6, the way light waves travel is addressed using both conceptual and mathematical models. Throughout this unit, the direction of this travel is manipulated through the use of instruments like microscopes and telescopes, in support of Enduring Understanding 6.E.
When light enters a new transparent medium, like the crystalline lens of your eye or the glass lens of a microscope, it is bent either away or toward the line perpendicular to the boundary surface. This process is called “refraction,” as outlined in Essential Knowledge 6.E.3. In both the eye and the microscope, lenses use refraction in order to redirect light and form images. These