The oil immersion objective lens provides the most powerful magnification, with a whopping magnification total of x when combined with a 10x eyepiece. But the refractive index of air and your glass slide are slightly different, so a special immersion oil must be used to help bridge the gap. Without adding a drop of immersion oil , the oil immersion objective lens will not function correctly, the specimen will appear blurry, and you will not achieve an ideal magnification or resolution.
Oil immersion lenses are also available from some manufacturers in lower magnifications, and provide higher resolution than their "high dry" counterparts. There are several other objective lens magnifications available with utility for particular applications.
The 50x oil immersion objective, often used in place of the 40x objective, is used as a gold standard for observing blood smears. The 60x dry is sometimes chosen over a x oil immersion lens for higher magnification without the need to use immersion oil. However, the numerical aperture an indication of resolving power of an objective of a x dry objective is much lower than that of a x oil immersion objective and, as a result, the ability of the lens to resolve fine details in the specimen is much lower, too.
It is important to always use the correct immersion media e. Categories Blog. View wishlist Shopping Cart: 0 Items. Your shopping cart is currently empty. Close Checkout. View cart Your Wishlist: 0 Items. Your wish list is currently empty.
A common demonstration involves looking at the letter "e" on a slide. When you move the slide left, does the image move left or right? Problem 2: Everything is dark. Is the microscope plugged in? Is the power switch on? Is the objective lens snapped into position? Is the light control set correctly?
If you are on the highest power objective, did you forget immersion oil? Problem 3: I can't find anything on low power! Center the coverslip of the slide under the objective lens. Focus up and down with the coarse adjustment knob. Problem 4: When I moved to a higher power, everything disappeared!
Return to the previous lower power objective. Center the object in the field of view. Go to the higher power objective and use only the fine focus.
Problem 5: The image is blurry on all powers. Clean the microscope's ocular lens. Only use lens paper! If you rotate the ocular and the specks move, there is dirt on the ocular lens and it should be cleaned. Clean the slide. A tissue, paper towel, or cloth can be used. Problem 6: The image is blurry only on a particular power. If you move it, you will have it in the wrong position.
If your scope has the knob, find out where it is and avoid it. This is directly under the hole in the stage where light passes through to the slide. It is controlled by a level which opens and closes an iris to let more or less light through the slide. In some specimens there is not much contrast between the colours and shades of the different components being magnified.
Changing how bright the view is by adjusting the diaphragm can allow you to better see some of the details you are trying to magnify. There is a compound microscope for each student. Carry out the activities listed below and fill in the blanks as you do so. Skip to main content. Module 4: Microscopy I — The Basics. Search for:. The Parts of a Compound Microscope and How To Handle Them Correctly Information Many important anatomical features, especially those that function at the tissue or cellular levels, are too small to be seen by the unaided eye.
Lab 4 Exercises 4. Pick up your microscope and physically move it to a new location. Bring it close enough that you can look into it comfortably from where you are sitting. Arrange it so that the stage is facing you and the eyepiece is rotated towards you.
What part of the microscope did you grab in order to pick it up and move it? Where are the locations of the two stage adjustment knobs on your microscope? Where is the location of the coarse focus knob? Where is the location of the fine focus knob? Is there a condenser adjustment knob? If so, where is it located? Find the diaphragm lever.
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