Microscope NotesThe compound microscope is a useful tool for magnifying objects up to as much as 1000 times their normal size. Using the microscope takes lots of practice. Follow the procedures below both to get the best results and to avoid damaging the equipment. Show
Field of ViewThe field of view is largest on the lowest power objective. When you switch to a higher power, the field of view closes in towards the center. You will see more of an object on low power. Therefore, it is best to find an object on low power, center it, and then switch to the next higher power and repeat. Depth of FocusThe depth of focus is greatest on the lowest power objective. Each time you switch to a higher power, the depth of focus is reduced. Therefore a smaller part of the specimen is in focus at higher power. Again, this makes it easier to find an object on low power, and then switch to higher power after it is in focus. A common exercise to demonstrate depth of focus involves laying three different colored threads one on top of the other. As the observer focuses down, first the top thread comes into focus, then the middle one, and finally the bottom one. On higer power objectives one may go out of focus as another comes into focus. Microscope TroubleshootingProblem #1: The image is upside down and/or backwards.
Problem #2: Everything is dark.
Problem #3: I can't find anything on low power!
Problem #4: When I moved to a higher power, everything disappeared!
Problem #5: The image is blurry on all powers.
Problem #6: The image is blurry only on a particular power.
Microscope DrawingsWhen drawing what you see under the microscope, follow the format shown below. It is important to include a figure label and a subject title above the image. The species name (and common name if there is one) and the magnification at which you were viewing the object should be written below the image. All relevant parts of the drawing should be labelled on the right side of the image using straight lines. Lines should not cross. Drawings should be done in pencil, while labels should be in pen or typed. Remember that total magnification is determined by multiplying the ocular x objective. Viewing Prepared Slides*** Don't hoard slides! You can only view one at a time, so that's all you should be holding. Return it before getting another, and if you break it, tell your instructor so that it can be properly cleaned up and replaced! ***
Making a Wet Mount (Live Prep) Slide
Further InvestigationDigital microscope for Macintosh or Windows Investigating pondwater organisms Powers of 10 (1977 version) Make your own microscope Why must the specimen be centered before switching to a higher magnification quizlet?The specimen must be centered in the field of view on low power before going to high power because on high power, it is difficult to find the specimen.
Why should you put the specimen in the middle of the field before changing the power?The field of view in a microscope is highest on the lowest power objective. When one switches to higher magnification power, the field of view is more concentrated towards the center. Therefore one can see the object more clearly on lower power.
Why is it essential to position the specimen in the center?Make certain that the portion of the specimen you wish to view is exactly centered in the field of the low-power objective. This is necessary because the microscopic field of view is smaller under high magnification than under low magnification.
Why do you need to focus the specimen under the lowest magnification first before switching to a higher magnification?The depth of focus is greatest on the lowest power objective. Each time you switch to a higher power, the depth of focus is reduced. Therefore a smaller part of the specimen is in focus at higher power. Again, this makes it easier to find an object on low power, and then switch to higher power after it is in focus.
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