Reason 1: protect the objectives from damage If you focus the high power objectives with the coarse focus knob, then you risk slamming the objective into the slide, risking the damage of both. Some high power objectives are spring-loaded, with a front-part that retracts when touched by the slide. This is a protective mechanism.
• Calculate the total magnification that you used to draw the slide on high power (refer back to Introduction if needed). _____ Go back to the slide catalog and choose “Human” then “Blood” • Observe the slide under the 4x, 10x, 40x, and 100x objectives using the course focus, fine focus, and light adjustment to obtain a clear view.
Aug 24, 2010 · objective lens (usually 4x) because all the other ones are too long and the coarse adjustment knob may bring the slide up too qucikly, therefore it might break the slide or crush the specimen being...
BIOS242 Lab 3 Name: Fine adjustment knob: small, round knob on the side of the microscope used to fine-tune the focus of your specimen after using the coarse adjustment knob Aperture: the hole in the stage that allows light through for better viewing of the specimen Parfocal microscope objectives: The specimen being observed remains in focus when magnification is changed; i.e., …
NEVER USE THE COARSE FOCUS KNOB ON HIGH POWER! The high power lens should be very close to your slide when in proper focus. If you turn the coarse adjustment knob while on high power, the objective could easily break your slide.
The coarse adjustment knob is used ONLY with the low power (4X, 10X) objectives. When focusing under the 40X or 100X objective, ONLY use the fine adjustment, never the coarse adjustment.
Coarse and fine adjustment The coarse adjustment knob should only be used with the lowest power objective lens. Once it is in focus, you will only need to use the fine focus. Using the coarse focus with higher lenses may result in crashing the lens into the slide.
Never use the coarse adjustment knob when focusing with the high-power or oil immersion objectives in place as this can damage the objective or the slide.Dec 14, 2021
the Fine Focus KnobUse the Fine Focus Knob to bring the image into focus. When using 10x and 40x objectives, use ONLY the fine focus knob so that you don't scratch a lens or break a slide.
Why should the fine focus knob typically be used with the 10x and 40x objective lenses? The slide should be close to in focus after focusing at the 4X objective. Focusing with the course focus knob would result in too large a change in focus.
The light intensity decreases as magnification increases. There is a fixed amount of light per area, and when you increase the magnification of an area, you look at a smaller area. So you see less light, and the image appears dimmer. Image brightness is inversely proportional to the magnification squared.Apr 17, 2018
What happens if you try to use the coarse adjustment when the 10X lens is in place? The focus of the specimen would be unclear with a high objective power and the stage lifted high due to the coarse adjustment.
The body tube of the microscope should not be lowered while looking through the ocular lens because you do not want to lower the body tube too much and have it crack the slide. to move the body tube in order to focus on the specimen.
USE OF THE COARSE ADJUSTMENT MAY DAMAGE THE SLIDE AND THE LENS! You should notice that you can see the object, but it may be slightly out of focus.
COARSE ADJUSTMENT KNOB — A rapid control which allows for quick focusing by moving the objective lens or stage up and down. It is used for initial focusing. 5. FINE ADJUSTMENT KNOB — A slow but precise control used to fine focus the image when viewing at the higher magnifications.
The 100x lens is immersed in a drop of oil placed on the slide in order to eliminate any air gaps and lossof light due to refraction (bending of the light) as the light passes from glass (slide) → air → glass (objective lens).Sep 24, 2020
When light passes from a material of one refractive index to another (for example: from glass to air), it bends. In the space between the microscope objective lens and the slide (where air is), light is refracted, the light scatters and it is lost.
Before using immersion oil, make sure that your 100x objective lens is made for use with immersion oil.
Immersion oil should only be used if you have an immersion oil lens. The lens will actually have "oil", "immersion" or "HI" (homogeneous immersion) printed on it.
Your microscope has 3 magnifications: Scanning, Low and High. Each objective will have written the magnification. In addition to this, the ocular lens (eyepiece) has a magnification. The total magnification is the ocular x objective
1. Store microscopes with the scanning objective in place.#N#2. Wrap cords and cover microscopes.#N#3. Wash slides in the sinks and dry them, placing them back in the slide boxes to be used later .#N#4. Throw coverslips away.
Types of Microscopes. Light Microscope - the models found in most schools, use compound lenses to magnify objects. The lenses bend or refract light to make the object beneath them appear closer. Common magnifications: 40x, 100x, 400x. Stereoscope - this microscope allows for binocular (two eyes) viewing of larger specimens.
1. Gather a thin slice/peice of whatever your specimen is. If your specimen is too thick, then the coverslip will wobble on top of the sample like a see-saw, and you will not be able to view it under High Power.
Drawing Specimens. 1. Use pencil - you can erase and shade areas. 2. All drawings should include clear and proper labels (and be large enough to view details). Drawings should be labeled with the specimen name and magnification. 3. Labels should be written on the outside of the circle .