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How to Use a Biological Microscope for Beginners Sonic Supply

How to Use a Biological Microscope for Beginners

Microscopes open a door to a whole other world – one that can’t be seen with the naked eye. It’s an amazing experience to look through the lenses of a biological microscope, and if you’re reading this, it means that you’re excited to get started. In this blog, we’ll discuss what a biological microscope is, how to handle it, prepare a microscope slide, and see your sample. Let’s go!

                          Allium Root Tip Under a Biological MicroscopePurple Allium Flower
                                            Allium Root Tip                                 Allium Flower

What is a Biological Microscope?

There are over seven distinct kinds of microscopes, but we’re only going to be focusing on one today. Biological compound microscopes are commonly found in science classrooms, and they are perfect for viewing transparent biological specimens such as plant cells. The light at the bottom of the microscope shines through, allowing the objective lenses to pick up the very tiny, less transparent details. Imagine if you were to hold up a piece of paper with writing on one side up to the light, with the writing facing away from you. You would be able to see through the paper and distinguish the words because the ink makes the paper less transparent in those areas.

What are the Parts of a Microscope?

Biological Microscope Diagram

This diagram illustrates and identifies each part of a biological microscope. But what do they do? Let’s explain some of the most important moving parts:

Objective Lenses

There are three different objective lenses with three different magnifications. The shortest objective lens has the lowest magnification, the second shortest lens has medium magnification, and the longest lens has the highest magnification. By twisting the nosepiece, you can choose which magnification you would like to use.


The stage is where your microscope slide will be held. It has a lens in the middle to allow light to reach your specimen. The stage can move up, down, left, right, forward, and back.

Slide Holder

These are clips on the stage that help hold your slide in place. The slide itself should not move during viewing. Instead, you move the stage to get the slide properly illuminated.

Fine and Coarse Focus

Both the coarse focus and the fine focus move the stage up and down, to be closer or further away from the objective lenses. The coarse focus moves the stage by large increments, while the fine focus moves the stage by small increments.

It’s important to note that you should NEVER use the coarse focus while on the highest magnification. If the objective lens hits your microscope slide, it can damage both the slide, specimen, and the objective lens.

Stage Adjuster

These knobs move the stage left, right, front and back. One knob, either the top or bottom, will move it left and right, while the other moves the stage front and back.

How Should I Handle My Microscope?

When moving or transporting your microscope, hold it with one hand on the base, and one hand on the arm. When you’re done with your microscope, set it to the lowest magnification, then use the coarse focus to move the stage as low as it will go. If your microscope is plugged into the wall, make sure you remember to turn off the light using the on/off switch before you unplug the unit. It’s also considered courteous to others, if you’re sharing a school microscope, for example, using a gentle disinfectant around the eyepiece and any other areas you’ve touched. Follow these tips and you’ll be a pro in no time!

How Do I Prepare a Microscope Slide?

There are a few different ways to prepare a microscope slide (click ), but the main ways are wet mounts, dry mounts, and smear slides.   

Wet Mounts

A wet mount being prepared on a biological microscope

Wet mounts are used when you have a liquid specimen or a live specimen that needs to stay wet. If you’re going to be looking at a liquid specimen, place a drop of the specimen in the middle of a slide and gently cover it with a cover slip. A cover slip is a thin square of plastic that keeps the sample from falling off the slide or contacting the objective lenses (click here to see our range of cover slips). Ensure that there aren’t any air bubbles and gently wipe away any excess liquid with a paper towel. If you’re looking at a specimen that needs to stay wet, then you should place the specimen on the slide and cover it with a drop of water and a cover slip. Place the slide in between the slide holders.

Dry Mounts

Insect leg under a biological microscope

Dry mounts are for samples that don’t need to be wet, or won’t dry out quickly, like insect legs or flower petals. They follow the same process as the wet mount without water involved!

Smear Slides

A smear slide being prepared

Some liquid specimens, like blood, require a smear slide. Place a drop of the specimen onto the slide. Then, take a second slide and use the edge to drag the specimen across the first slide. Place a cover slip over the specimen, guarantee there are no air bubbles, and get to viewing!

How Do I See Anything?

Once you’ve placed your slide onto the stage, turn your light on. Use the stage adjusters to move your sample into the middle of the light, then look through the lowest magnification. It might look like a whole lotta nothing – a blank screen. If that’s the case, try using the coarse focus to bring the sample up closer to the objective lens.

Once you see something, even if it’s super blurry, stop using the coarse focus and switch to the fine focus until your specimen is clear. When your specimen is clear, you can move up to a higher magnification, and remember to check that the lens doesn’t accidentally hit the slide. 

If you still don’t see anything, you may need to move the stage more to the left or right or use the fine focus to move the sample farther away from the objective lens, instead of closer. Keep in mind that if your specimen is moving it will be difficult to focus on it for more than a few seconds at a time.

Using a microscope takes a lot of patience, but the results are worth it!


For more information, take a look at our blog Things to Consider Before Purchasing a Microscope.

Sonic Supply has an excellent range of microscopes to choose from, check us out!









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