One of the fun parts of using a microscope is learning how to prepare a microscope slide like a professional. There’s more to it than meets the eye, but with a little practice you can prepare any specimen for careful analysis. In this article we’ll explain the basics of how to prepare a microscope slide, including a dry mount, wet mount, and we’ll even discuss staining specimens when prepping your slides.

The Basics: What is a Microscope Slide?

A microscope slide is a rectangular piece of glass or plastic, onto which you place the specimen you hope to view with your microscope. There are several ways to mount your specimen to the slide (more on that in a moment), but once your specimen is mounted, you’ll use a thin, square piece of glass or plastic (called a “coverslip”) to cover the specimen on the slide so that it is sandwiched securely and ready to view.

Using a Dry Mount When Preparing a Microscope Slide
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A dry mount is generally used when you’re preparing slides with inanimate objects (objects which do not require water to survive), and it is called a dry mount because you will mount your specimen to your microscope slide without adding any water to the slide first. The steps to a successful microscope slide dry mount are:

• Place your slide on a flat, clean surface.
• Lay the specimen on top of your slide (it’s always best to use as thin a specimen as possible, a single cell-layer thickness is ideal).
• Place your coverslip on top of the specimen, being careful to keep it as flat as possible.

That’s all there is to a dry mount, now you can slip your prepared microscope slide under your microscope and view your specimen!

Using a Wet Mount When Preparing a Microscope Slide
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Unlike a dry mount, a wet mount requires the use of water. The four components needed to prepare your microscope slide using a wet mount are your slide, water, specimen, and coverslip. This is the method of choice if you’re viewing living specimens which require water to remain alive. The steps to a successful microscope slide wet mount are:

• Place the slide on a clean, flat surface.
• Place a drop of water on the slide and then add the specimen to the drop of water. Some people prefer to place the specimen first and then add the water … it’s really personal preference.
• Hold the coverslip carefully by its sides when placing it. Holding the coverslip at a 45 degree angle and laying the bottom edge close to the specimen helps for a good, tight mount.
• Lower the coverslip so that the water is spread out evenly between the microscope slide and coverslip. Sometimes you will see air bubbles (they’ll look like small doughnuts), and these can be removed by gently pressing on the coverslip to move them toward the edge where they can escape. If you notice that there are dry areas, add a little water to the edge of the coverslip. Wipe off any excess with a dry cloth or paper towel.

And that’s a successful wet mount! While it is a bit more involved and intricate than a dry mount, there’s a real satisfaction which comes after successfully completing the perfect wet mount.

Staining Specimens When Preparing a Microscope Slide
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There will be times when additional contrast is needed on your slides to successfully analyze specimens under your microscope. Common stains that scientists use for this are Lugol’s Iodine, Methylene Blue, or Crystal Violet. You can add the stain directly to the water when you first prepare your wet mount, or you can view your specimen first, and then add the stain later, to view the specimen in two different ways during your analysis. You should always wear gloves when handling stains so your skin isn’t dyed, and you should never ingest the above stains.

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