There are several reasons why you should use the coarse focus knob only with the 4x objective and not with the high power objectives. 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.
The fine adjustment knob is the smaller of the smaller of the two knobs and is located further away from the arm of the microscope. Most coarse and fine adjustment knobs are built with coaxial control in line with one another so you can easily switch from using the coarse focus adjustment knob to using the fine focus adjustment knob.
This preview shows page 4 - 7 out of 8 pages. DO NOT USE THE COARSE ADJUSTMENT KNOB WHEN USING THE 40X LENS OR HIGHER MAGNIFICATION. Even if you are going to use the 100X lens, start by focusing your specimen with the 4X or 10X magnification.
The coarse adjustment knob is the bigger of the two knobs and is located closest to the arm of the microscope. The fine adjustment knob is the smaller of the smaller of the two knobs and is located further away from the arm of the microscope.
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.
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. There is a warning it is not good to change coarse focus under high power.
Use the Coarse Focus Knob to bring the image into focus. 7. Use 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 do you need to start with 4x in magnification on a microscope? The 4x objective lens has the lowest power and, therefore the highest field of view. As a result, it is easier to locate the specimen on the slide than if you start with a higher power objective.
A: Only use the fine focus with the 40X and 100X objectives; can use the coarse focus with the 4X and 10X objectives.
Never go back to the 10x or 40x objectives after you have applied oil to the specimen since oil can ruin the lower power objectives. [The 4x objective can be used because it is high enough to be above the oil.] 7.
The gearing mechanism of the adjustment produces a large vertical movement of the stage with only a partial revolution of the knob. Because of this, the coarse adjustment should only be used with low power (4X and 10X objectives) and never with the high power lenses (40X and 100X).
When switching to the 100x lens, what should you use? 100x lenses should be used with a few drops of immersion oil to enhance the image.
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.
If switching between a dry 40x lens and a 100x oil lens, care must be taken not to get oil on the 40x lens, which could damage it.
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 coarse focus knob would result in too large a change in focus.
The coarse adjustment knob on most microscopes is along the lower middle part of the arm of the microscope as shown in the image below.
The basics of using a microscope tells us that we should start with the lowest power objective first and with the stage at its lowest position.
If your eyepiece (s) on your microscope is built facing away from the arm of the microscope then turning the knob away from you will raise the stage and turning the knob towards you will lower the stage.
Some microscopes will come with a tension adjuster. This allows you to manipulate the tension of the adjustment knob to determine how soft or how hard do you have to turn the knob to attain the desired level of movement from each revolution of the knob.
Knowing the difference between fine adjustment and coarse adjustment knobs on the microscope is an integral part of focusing the microscope.