Inquiry 8: How Does It Work? Binoculars, Periscopes, and Kaleidoscopes
Binoculars are really just two refracting telescopes joined together with a hinge. Soon after telescopes were invented, people started to fasten two of the long tubes together to make binoculars. These long binoculars, however, were heavy and difficult to handle. Since it was difficult to keep these tubes parallel to one another, the image seen was often doubled.
Around 1900 a German physicist named Ernst Abbe made a pair of binoculars using prisms that reflected the incoming light twice. This meant that it was possible to make a shorter instrument. Also, by using two prisms the image that formed appeared right side up.
Binoculars are currently found in three designs: 6x30, 7x50, and 8x30. The first number refers to the magnification of the binoculars and the second number gives the diameter of the objective lens in millimeters. When using binoculars, you look at an object and light reflects off the object and enters the front of the binoculars through the objective lens. This forms an image that is upside down and reversed. Prisms correct the image before we see it through the magnifying eyepiece lenses.
Life Science - Use binoculars to observe birds. Record some of the following features used for the identification of birds: the shape and color of the eyes, feet, color of the plumage, shape of the head, shape of the tail feathers, and beak shape and color. You may also want to sketch what you observe. Then, using guidebooks for the identification of birds, try to determine what kind of birds you were watching.
Periscopes are instruments that allow the viewing of objects that are not in the direct line of vision. They are often found in submarines and may have tubes up to 10 meters long. Tanks also contain periscopes that allow people inside of a tank to view the surrounding area while remaining protected inside of the vehicle. The development of fiber optics led to the development of other types of periscopes that allow doctors to view inside the human body without having to perform major surgery. These types of periscopes are called endoscopes or cystoscopes and are very useful in the medical field.
Make a Periscope - Construct a periscope by using the directions that follow. This activity will allow you to experiment with mirrors and the correct placement of them in the scope.
The kaleidoscope was invented by Sir David Brewster around 1816 and patented the following year. The device uses the image-forming properties of combined inclined mirrors. Depending on the number of mirrors and the angle between them, the kaleidoscope will produce multiple symmetrical patterns. Since its introduction, the kaleidoscope has been sold primarily as a toy, but has practical uses as well.
A simple kaleidoscope is made of two thin, wedge-shaped mirror strips touching along a common edge or a single sheet of bright aluminum bent to an angle of 45 or 60 degrees. The mirrors are enclosed in a tube with a viewing eyehole at one end. At the other end is a thin, flat box that can be rotated. This flat box is made from two glass disks, the outer one ground to act as a diffusing screen. In this box are pieces of colored glass or beads. When the box is turned or tapped, the objects inside tumble into different groups and when the diffusing screen is illuminated by natural or artificial light, six or eight different symmetrical images appear. The number of combinations and patterns is without limit.
There are five different types of kaleidoscopes. The chamber kaleidoscope has an enclosed object case with free-tumbling jewels, glass, beads or other objects. The liquid chamberscope has an object case filled with liquid (usually glycerin) in which the jewels, glass beads, or other objects float. The wheel scope has one or more wheels at its objective end that may contain glass, translucent rocks like agates, pressed flowers, beads, jewels, or other objects. The refillable scope features a removable object chamber. The contents of this chamber can be changed and users can experiment with their own assortment of colors and objects. The teleidoscope uses mirrors and lenses alone so that anything that is viewed, is multiplied.
Make a Pringles Can Kaleidoscope - Design your own kaleidoscope out of a Pringles can with the following directions.
Make a Paper Towel Roll Kaleidoscope - Design your own kaleidoscope out of a paper towel roll with the following directions.
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