Microscope and Its Uses (1949)

[Music] the microscope is one of the most useful instruments you'll use in your study of science it is one of the oldest and most universally used of all Optical instruments and the microscope is just as essential for your work as a student as it is for the work of the trained scientist there are many types of microscopes some more elaborate than others some made for special purposes but essentially they are all for the same purpose to magnify plant and animal life and other matter of minute size to a degree agree that it may be seen studied the powerful eye of the microscope extends the range of your eye when you use it correctly the microscope is your window into the world we seldom see a world of strange creatures a world where a single drop of water may be teing with scores of one- celled animals and yet this strange World is Yours to explore yours to investigate by means of your microscope as the first step in learning to use the microscope we must become familiar with the names of the main parts of the standard instrument the base is so named because it supports the microscope it is fairly heavy to make the instrument stable the stage may be compared to the stage of a theater it holds the specimen to be viewed and therefore is where the action takes place the objectives are the lenses which are nearest the specimen or Slide the objectives are attached to the revolving nose piece which allows the objectives to be easily changed the tube is part of the main body of the microscope so named because of its tubular shape the eyepiece is the lens located at the top of the tube nearest the eye the adjusting knob is used for focusing and the mirror for reflecting light onto the specimen an additional focusing knob is found on most modern microscopes it is used for critical focusing which we'll learn more about shortly so you're ready to begin using the microscope care in moving the instrument from place to place is one of the first precautions you must learn always carry the instrument by gripping it firmly carry it carefully in front of you and keep it upright so the eyepiece can't drop out in using the microscope the first step of preparation is in making certain that all lens surfaces are clean and free of dust and lint if the instrument hasn't been used for a Time the lenses will probably need cleaning use lens tissue never your handkerchief and gently clean the objectives and the eyepiece the glass from which the lenses are made is soft and easily scratched so be very careful then unless you are instructed otherwise tilt the microscope body until it is in a comfortable position for you to use adjusting the mirror for the best light is your next problem place a slide on the stage and direct the light onto the portion of the slide that you'll be viewing turn the low power objective into viewing position by revolving the nose piece the low power objective is the shorter of the two it'll snap into place now look into the eyepiece and turn the mirror slightly from side to side until the light appears to be even and comfortably bright turn the low power objective down with the adjusting knob until it nearly touches the slide but watch carefully if you turn too far you may break the slide and damage the microscope now look through the eyepiece and focus by turning the adjustment knob toward you until the specimen on the slide becomes distinct then use the fine adjustment knob to bring the specimen into sharp Focus this is called critical focusing most your studies of the small plants and animals will done using the low power objective since the low power gives you a better overall view of most plant and animal structure you will use the high power objective in some of your studies of cell structure however and it is important to know how to use it correctly first turn the revolving nose piece until the high power objective snaps into place now before focusing carefully adjust the high power objective until it is is very near the top of the glass slide in focusing the high power objective turn the course adjustment knob toward you until you begin to see an image then slowly turn the fine adjustment knob back and forth until you're sure the specimen is in clear sharp Focus care in critical focusing will produce a clear sharp image that is easy to see in study a person trained in the use of the microscope learns to keep both eyes open while viewing the specimen this helps avoid ey strain and makes the work less tiring you can learn this technique too now don't squint try leaving both eyes open and covering one eye with your hand concentrate on The View through the microscope then slowly remove your hand doesn't work we'll try it again don't it'll come to you and it'll help to make your work much easier and now let's review the most important rules for using a microscope handle the instrument carefully it is delicate and expensive keep the lens surfaces clean with lens tissue adjust the mirror for even comfortably bright light carefully adjust the objectives to a position near the slide then Focus first with the course adjustment and complete the focusing with the fine adjustment both eyes open while studying the specimen remember that by mastering the use and operation of the microscope you are preparing yourself to use and understand even more