Biology lab Microscope

Explain the difference between ocular and objective lenses.

The ocular lens, which is also called the eyepiece lens, is positioned at the top of the optical tube, while the objective lens is positioned at the bottom. Both of these lenses have important roles in magnification, but the objective lens also has other defined roles, such as resolving power.

Objective Lenses

The pattern of light formed by the specimen is focused into a real image by the objective lenses. When the proper illumination is provided the resolving power of a microscope depends on the quality of its objective lenses. There are four of them with magnifications of 4X, 10X, 40X, and 100X.

What actually happens to the specimen when you move the mechanical stage to the away from you?

When you move a slide away from you, the object appears to move towards you.

Does the diameter of the field or the area actually covered in the slide increase or decrease as you increase the magnification power from 40 (4X10), to 100 (10x10) to 400 (40x10)?

decrease

Does the working distance between slide and lens increase or decrease as you increase the magnification power from 40 (4X10), to 100 (10x10) to 400 (40x10)?

decrease

What parts are related with magnification?

microscope has two systems of lenses for greater magnification, 1) the ocular, or eyepiece lens that one looks into and 2) the objective lens, or the lens closest to the object.

Which (total) magnification makes easier to find something with the microscope?

scanning 4x

What parts allow you to control the light intensity?

Iris Diaphram lever Controls the intensity of the light coming from the bulb.

Fine Focus Adjustment Knob

this part moves the stage slightly to help you sharpen or "fine" tune your view of the specimen

Which (total) magnification was better to determine the size of only the dot of the letter "i"?

40x

What happened to the orientation of the letter "e" when observed under the microscope?

The letter should be upside down and reversed.

Which (total) magnification was better to determine the size of the whole letter "i"?

4x

What was the approximate size of the diameter of the field for each total magnification used in the lab?

?

What parts control the X, Y, and Z (vertical) movement of the slide?

?maybe If your microscope has a mechanical stage, you will be able to move the slide around by turning two knobs. One moves it left and right, the other moves it forward and back.

Name the 4 types of objective lens that are on the microscope and what is their objective magnification and total magnification?

1. Scanning Lens - 4X, 40X2. Low Power Lens - 10X, 100X3. High Power Lens - 40X, 400X4. Oil Immersion - 100X, 1000K

Objective lens

Lower lens

Explain how you determine the TOTAL magnification when using the microscope

Multiply the magnification of the lenses together. For example, if the eyepiece magnification is 10x and the objective lens in use has a magnification of 4x, the total magnification is 10 × 4 = 40. The total magnification of 40 means that the object appears forty times larger than the actual object.

What objective lens should be used first when observing a specimen?

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.

What actually happens to the specimen when you move the mechanical stage to the right and left?

The image is always upside down, so what you see through a microscope shows up as the opposite of what you are doing. Any movement of the object also shows up in the opposite way. When you move an object to the right, it appears to move to the left, and when you move it up, its image moves down

Working Distance

The space between the front mount (bottom) of the objective lens and the top of the coverslip of the microscope slide is the working distance. The working distance decreases as the objective lens magnification increases.

Total Magnification

The total magnification of the lens system is the product of the magnification the ocular times the magnification of the objective lens being used (ocular X objective).

Coarse Focus Adjustment Knob

This is used for rapid (or coarse) focusing on the specimen when using the scanning objective lens and the low power lens.

Mechanical Stage Adjustment Knobs

Two knobs that are located on the side of the stage and are used to move the slide around to locate your specimen. one knob moves the slide from side to side and the other moves the slide forward and backward. The mechanical stage permits precision movements of your slide , without you touching the slide yourself

Ocular lens

Upper lens (eye piece)

What objective lens gives the best magnification?

When coupled with a 10x (most common) eyepiece lens, total magnification is 40x (4x times 10x), 100x , 400x and 1000x. To have good resolution at 1000x, you will need a relatively sophisticated microscope with an Abbe condenser. The shortest lens is the lowest power, the longest one is the lens with the greatest power.