[pic] HISTORY OF MICROSCOPE Oddly enough, the compound microscope was invented before the single lens microscope. But the instruments were not very good to start with and much more could be seen with very small lenses of short focal length. In about 1597 two Dutch eyeglass makers, Zaccharias Janssen and his son Hans were experimenting with lenses in a tube. They observed that nearby objects viewed through two lenses in line were magnified. Their device was the first compound microscope
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eventually become reinfected because the germs would have spontaneously generated. But the curved-neck flask never became infected, indicating that the germs could only come from other germs A compound light microscope is a microscope with more than one lens and its own light source. In this type of microscope, there are ocular lenses in the binocular eyepieces and objective lenses in a rotating nosepiece closer to the
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of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Lens A lens is an optical device which transmits and refracts light, converging or diverging the beam. Thin Lens Equation A common Gaussian form of the lens equation Linear magnification Numerical quantity that determines the scale of the image produced by an objective. It is equal to the ratio of the lengths l and l’ of
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Binding Between Ocular Lens Crystallins Linked to Cataract Formation Abstract As biological resistance against cataracts, proteins called α-crystallins in the lens of the eye are present to keep denatured crystallins from precipitating and forming cataracts. Over time, these α-crystallins are increasingly bound to denatured proteins and contribute to the conglomeration of other crystallins themselves. Since the eye does not replace these essential proteins, the incidence of cataract formation increases
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Phase Contrast Microscopy Phase Contrast Microscopy, first described in 1934 by Dutch physicist Frits Zernike, is a contrast-enhancing optical technique that can be utilized to produce high-contrast images of transparent specimens, such as living cells (usually in culture), microorganisms, thin tissue slices, lithographic patterns, fibers, latex dispersions, glass fragments, and subcellular particles (including nuclei and other organelles). In effect, the phase contrast technique employs an optical
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positive lenses and observed. Using the thin-lens equation, the focal length of three given lenses were examined and used to find the angular magnification of the microscope. After the angular magnification was calculated, a to-scale ray diagram was drawn to identify the findings. 1. Introduction A compound microscope has a magnification by two lenses. One of the lenses is objective, which produces a bigger image of the object. The second is an eyepiece lens that is used like a simple magnifier to
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Chapter 15: Refraction and Lenses Refraction of Light If water waves in a ripple tank travel from water with a depth of 1 cm into a shallow area with a depth of .3 cm, the water will slow down. In a ripple tank the depth can be changed by placing a sheet of plexiglass or glass in the water. In the picture to the right the area to the left is deeper water and the the the right is shollow. The picture shows that when the water travels into a shallow area and slows down, the wavelength will
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front of the retina instead of on the retina, which results in blurred vision. This occurs when the eyeball becomes too long and prevents incoming light from focusing directly on the retina. It may also be caused by an abnormal shape of the cornea or lens. Myopia can affect both children and adults. Some of the signs and symptoms of myopia include: * Headaches * Eyestrain * Squinting * Difficulty seeing distant objects, such as highway signs Myopia can be corrected with eyeglasses
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14. To your diagram, add the cells of the non-neural retina. 15. Name the glial cell found in the retina. 16. Draw a rod and a cone, showing outer segment, inner segment, mitochondria, nucleus and synapse. 17. Explain how the cornea and lens function to focus an image of the external scene on the retina. 18. Explain why everything looks blurred if you open your eyes under water, and why you can see perfectly well when you have a face mask (relate this to Snell’s Law of refraction
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contains a platform with a hole beneath it. The object for examination rests upon the platform over the hole, and light passes through the item from either a mirror or lamp under the hole. The image passes through the lens of the microscope which magnify it several times, depending upon the lens used. Different with the microscope and the naked eye with the letter e? * Ink under the microscope appears different from the normal view. It completely looks different. You can see the details clearly
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