Biology Microscope Basics

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Questions and Answers

What is the proper way to carry a microscope?

Always carry the microscope with two hands and grasp the arm of the microscope with one hand and place the other under the base. Always holding it in an upright position so the eyepiece doesn't fall and do not swing the microscope. Place the microscope at least 6 to 8 inches from the edge of the desk.

What is the diaphragm of the microscope used for?

The diaphragm on the microscope is used to change the amount of light that is being allowed to enter through the slide.

What is the difference between the fine and coarse adjustments?

The coarse adjustment moves the objectives further or closer to the slide on the stage, while the fine adjustment brings the object specimen into sharp focus.

If your microscope lens is dirty, what should you use to clean it?

Lens paper Signup and view all the answers

What happens to the light intensity as you adjust the diaphragm?

As you open the diaphragm its widest, the most light is able to enter because it is open allowing all the light to come in. Signup and view all the answers

What happens to the size of the field of view of a microscope when you switch from low-power to high-power?

The field of view becomes a lot smaller, so you are able to see a lot less of the object instead of it fully. Signup and view all the answers

Explain why it is important not to use the coarse adjustment knob after you have moved to a power other than low.

Using the coarse adjustment knob after moving to a higher power could break the slide or damage the lens. Signup and view all the answers

When preparing a wet mount slide, why would you want to avoid trapping air bubbles under the cover slip?

Trapped air bubbles look like big blobs which can prevent you from seeing your specimen. Signup and view all the answers

Compare the position of the letter E as seen with the microscope to the position of the letter E on the slide. How has it changed?

Under the microscope, the E is upside down and backwards compared to the letter E on the slide. Signup and view all the answers

When you move the slide to the left of the stage, in what direction does the image appear to move?

The image appears to move to the right. Signup and view all the answers

When you move the slide away from you on the stage, in what direction does the image appear to move?

The image appears to move in your direction. Signup and view all the answers

What part of the microscope produces light?

The illuminator Signup and view all the answers

What is the purpose of the objectives?

To be able to focus in on an object or specimen and magnify it. Signup and view all the answers

Explain why a specimen that you wish to view with a compound light microscope must be very thin.

A compound light microscope shines a light through the specimen, so if the specimen is thick, light won't be able to pass through. Signup and view all the answers

What happens to the brightness of the field of view when you change from low-power to high-power?

The brightness of the field of view becomes a lot lower. Signup and view all the answers

How does color paper look different under high power? How does this demonstrate better resolution?

Under high-power magnification, paper appears as a tangled mass of fibers. Signup and view all the answers

How many times is the magnification increased when you change from low-power to high-power?

Four times Signup and view all the answers

How many times is the diameter of the field decreased when you change from low-power to high-power magnification?

How do you find total magnification?

Power X ocular (10x) Signup and view all the answers

The formula used to find the high-power field diameter is ____.

Low-power field diameter X low-power magnification / high-power magnification Signup and view all the answers

How to focus the microscope?

Locate the course adjustment knob which moves the objectives up-and-down. Practice moving it to see how it moves the objectives. Turn the course adjustment so that the low-power objective is positioned about 3 cm from the stage. Turn the revolving nosepiece until you hear the high-power objective click in position. Turn the nosepiece until the low-power objective clicks back into position. Raise the low-power objective by turning the course adjustment knob. Place a prepared slide on the stage so that it is centered over the stage opening. Use stage clips to hold the slide in position. Open the diaphragm to its widest to allow the most light to enter. Look at the microscope from the side and turn the course adjustment so that the low-power objective is as close as possible to the stage without touching it. Look through the eyepiece and turn the course adjustment to move the low-power objective away from the slide until the object comes into focus. Keep both eyes open while looking to avoid eyestrain. Once focused, turn the fine adjustment knob to bring the object into sharp focus. Once in focus, you may wish to adjust the diaphragm for clarity. Draw what you see. Rotate the nosepiece until the high-power objective clicks into place, look through the eyepiece and turn the fine adjustment knob to focus again, and draw what you see. Signup and view all the answers

How to prepare a wet mount slide?

Obtain a clear glass slide, also clean. Obtain a clear glass coverslip—handle with care as they are sharp and fragile. With an eyedropper, get a sample of pond water and place one drop in the center. Hold the coverslip at a 45° angle to the slide and gently lower it to avoid air bubbles. Center the slide on the stage and turn the low power into position to bring the specimen into focus. If needed, switch to high power and try to identify organisms. Signup and view all the answers

Study Notes

Microscope Handling

Always carry a microscope with two hands: one on the arm and the other under the base.
Keep the microscope upright to prevent damage to the eyepiece.
Place the microscope 6-8 inches away from the desk's edge.

Microscope Components and Functions

The diaphragm regulates light entering through the slide.
The illuminator produces light for viewing specimens.
Objectives focus and magnify the specimen.

Adjustments and Focus

Coarse adjustment moves objectives closer to or further from the slide; fine adjustment sharpens focus.
Coarse adjustment should not be used at high-power to avoid damaging slides and lenses.
The field of view decreases significantly when switching from low-power (100x) to high-power (400x).

Specimen Preparation and Observation

Specimens must be thin for light to pass through.
Wet mount slides should prevent air bubbles to ensure clear viewing.
The letter 'E' appears upside down and backwards under the microscope.

Image Movement

Moving the slide left makes the image appear to move right.
Sliding the specimen away causes the image to seem to move towards the viewer.

Light and Magnification

Light intensity decreases with higher magnification due to a smaller field of view.
Paper viewed under high power shows detailed fiber structures, indicating resolution quality.
Magnification increases by four times when switching from low to high power, but the field diameter decreases by ten times.

Total Magnification Calculation

Total magnification = objective power x ocular power (10x).

Microscope Focusing Procedure

Use coarse adjustment to position the objective approximately 3 cm from the stage.
Secure the slide with stage clips and open the diaphragm for maximum light.
Adjust focus first with coarse, then with fine adjustment; maintain light for clarity.

Preparing a Wet Mount Slide

Use a clean slide and coverslip, adding a single drop of fluid to avoid overflow.
Lower the coverslip gently at a 45° angle to minimize air bubbles.
Center the slide on the stage and begin with low power for initial focus.

High-Power Field Diameter Calculation

High-power field diameter can be derived from the formula: Low-power field diameter x (low-power magnification/high-power magnification).

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Description

Test your knowledge on the proper handling and functions of microscopes in biology. This quiz covers essential safety tips and parts of the microscope, ensuring you're well-prepared for laboratory work. Perfect for biology students looking to sharpen their skills.