Lab Homework #1- Microscope Usage and Troubleshooting

When evaluating a blood film you use the 100x oil immersion objective. If your microscope has 10x ocular lenses what would the total magnification of the cells on the blood film be? 

1,000 times

I’m looking at a urine sediment using the 10x objective. I can get the sample focused using the coarse focus knob. I can’t seem to get the sample in focus when I move up to 40x objective when I use the coarse focus knob. How would I fix the issue?

Instead of using the coarse adjustment knob when switching to the 40x objective, use the fine adjustment knob instead. Since the sample is focused with the coarse adjustment already, all that needs done is slight adjustment with the fine adjustment.

After placing a microscope slide on the microscope stage the coarse focus knob is used to bring the specimen into initial focus.

True

There’s a spot in my viewing field, even when I move to a new field of view the spot stays in the same place. It’s still there, in the same place even when I change objectives. Blank #1: What part of the microscope has the problem? Blank #2: How would I fix the problem? (Think about what moves from one field of view to the next and what does not.) 

Eye piece and clean with lens cleaner and lens paper

Why should you not get oil on any other objective other than the 100x (oil immersion) objective?

You should not get oil on any other objective other than the 100x because it is very hard to clean off the 10x and 40x objective lenses. The 10x and 40x lenses are not made to touch the immersion oil therefore they cannot be cleaned as easily as the 100x. Not only is it a hard chore to clean but it can ruin the two lenses.

The oculars and objectives of a microscope should only be cleaned with what? 

Lens paper

The part of the microscope that you look through is called what?

Eyepieces (Oculars)

I’m looking at a stained peripheral blood film from a dog using the 100x oil immersion objective. The field of view is dark and I’m having trouble seeing anything. What could be done to improve the field of view so it’s not so dark? (There are multiple ways to accomplish this so list at least 3 ways to improve the situation. Be sure to include an explanation and what part of the microscope needs to be adjusted to receive full credit.)

- One way to make the field of view not so dark is to increase the light from underneath the stage using the Rheostat light control knob. This will allow for more light to shine through the sample in order to be visible
- A second way to make the field of view not so dark is to adjust the lighting with the condenser. The condenser allows for further control of illumination of the specimen and enhancement of the resolution. Again, using the condenser will take away the darkness by illuminating the specimen
- A last way to make the field of view so it is not so dark is to make sure that the field diaphragm is open as to however much is needed. The field diaphragm regulates the amount of light entering the condenser, so making sure it is in the right position needed will make it lighter.

I’m looking at a stained peripheral blood film from a horse using the 40x objective. Half of the field of view looks good, but the other half of the field of view is dark. How can this problem be fixed?

To fix this problem I would make sure that the objective lenses are fully clicked into place. This is most likely the problem because if they are not fully clicked into place you can see darkness on one side and the other side looks good.

The 40x objective may also be called what?

High dry

When I look into the microscope everything looks like I have double vision. I see two of everything. What needs to be adjusted on the microscope, so that only one image is seen?

Interpupillary distance adjustment ring

I’m looking at erythrocytes in the monolayer using the 100x oil immersion objective and I keep seeing things that look like bubbles. Sometimes they float by, but sometimes the field of view just becomes blurry and I can’t make it come into focus. What is causing this? How do I make it better?

Air bubbles in the oil and clean the slide and the objective lenses. You should reapply oil to ensure no bubbles are formed

When carrying a microscope, it should be held by what?

Arm and base