Elenco Fiber Optics Voice Data Kit - Manual (Page 17)

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Together they form an interesting and imaging combination
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You may have asked yourself, "What good is a piece of material composed of thousands of optical
fibers?" Why not just look through a piece of glass or plastic? In this experiment you will see how fiber
optics can be combined with lenses to focus an image that can be viewed at all angles...and solve a
difficult problem that we encounter if we use regular lenses.
M M M M aaa a tttt eeee rrrr iiii aaa a llll ssss N N N N eeee eeee dddd eeee dddd ::::
Ulexite (off-white, irregular-shaped rock)
10
Ч 10 Ч 2.5 mm (.4 Ч.4 Ч .1 inch) fiber optic faceplate
25 Ч 25 Ч 6 mm (1 Ч 1 Ч .25 inch) piece of plastic
Lens, double convex, approximately 25.4 mm (1 inch) diameter
Piece of white paper
FFFF OO O O LLLL LLLL OOO O W W W W TTTT HHHH EEEE SSSS EEEE SSSS TTTT EEEE PPPP SSSS ::::
• Find a room with one or more windows. Turn off the lights and shut all window coverings
except one.
• Hold the lens up in one hand and with your other hand
hold the piece of paper behind the lens. Turn your back to
the window so light is coming in over your shoulder. The
flat surfaces of the window, paper and lens should all be
parallel to each other. Hold the lens approximately 4 to 5
cm (1.6 to 2 inches) away from the paper. Focus the image
of the scene outside the window on it by moving the lens
either closer or further away from the paper to focus the
image as clearly as possible. (The distance from the lens to
the paper is slightly longer than the focal length of the
lens.)
• This time you will be facing the window and holding the
lens and Ulexite in front of you. Replace the paper with
the Ulexite and position the lens about the same distance
from the Ulexite that you found to best focus the image in
the previous step. Is the image you see on the surface of
the Ulexite upright or inverted?
• Replace the Ulexite with the fiber optic faceplate. What
are the differences between the images you see through
the Ulexite and the faceplate?
• Replace the fiber optic faceplate with the 25 × 25 mm
(1 × 1) piece of plastic. Can you see the same image on the
plastic as you did with the Ulexite and faceplate?
R R R R EEEE SSSS UU U U LLLL TTTT SSSS ::::
The lens should focus the image (or scenery) from the
window onto the white paper with a separation of 4 to 5 cm
(1.6 to 2 inches). The image will appear upside down (inverted).
The image formed by the lens onto the Ulexite will not be visible
from the lens side and only visible from the opposite side. The
image viewable on the Ulexite will be inverted and the same size
as it was when imaged onto the paper. The image formed by the
lens onto the faceplate will be identical in size and shape as the
image seen on the Ulexite, only clearer and without the
yellowish tint. No viewable image can be seen on either side of
the plastic piece, due to the lens.
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