Spectrum Scientifics Blog

Although everyone should enjoy our various sets of prepared slides sooner or later every avid microscope user will want to make their own slides.There are many ways for a slide maker to go about making his own samples.

First of all, before using any slide be certain to clean it thoroughly. Preferably with rubbing alcohol. Even if the slide is brand new, this will get any packaging materials off. Once clean, be sure to set up on a clean and flat surface.

With live liquid specimens, such as pond water or recently drawn bodily fluids, you should consider using concave slides. A simple eyedropper can be used to put the liquid into the cavity. That way the liquid will not slide around. There can be some issues with focusing the microscope to find things, as the liquid cavity has 0.5mm of depth; which is considerable focal range for a microscope. You can be looking at the bottom of the cavity, and then focus on the top. Since a lot of things in a liquid can be alive you might not always have an easy time locating various bacteria, paramecium, etc, but when you do the views are magnificent!

Slides of more ‘flat’ nature can also be made with liquids,especially when you do not have enough material to fill up a concave slide well. This is also a better method for less ‘alive’ liquids and it makes locating things with the microscope much easier than with concave slides. For this you will need simple flat slides as well as some cover slips. The easiest way to set this up is to use an eyedropper. Use the eyedropper to put a single drop of liquid on the center of the slide. Then take the coverslip and place one edge of it on the edge of the drop of liquid. Hold it at an angle and then let it drop onto the liquid.

This same technique can be used with water over a viewing sample that is dry. If you find that you have too much trouble mounting a dry specimen on a slide, simple place a single drop of water on top of the sample, and drop a coverslip same as before.

Sometimes water may not be enough to keep the viewing sample in place. This is where more advanced mounting mediums can be useful. They can be expensive to get, however, so in a pinch folks have used water down Elmer’s glue, which is clear when it dries. Its not the best substitute, but it can be useful at times.

Many times you may wish to stain a slide to bring out its features. There are many different types of stains; some with very specific purposes, other are more general (such as Methyl blue). Once again, in a pinch a home substitute of food coloring can be used. To stain the slide you need to follow the procedure for making a wet slide as above. Once you have dropped the slide cover onto the specimen, do not clean up the excess liquid. Instead, put a drop of the coloring on one side of the cover slip, then place a paper towel on the opposite side. As the paper towel soaks up the water it will draw the stain underneath the slide cover via wicking.

Of course for some specimens, you need to make pieces thin enough for them to be viewed with a microscope. For this you would need a microtome, which is designed to make ultra-thin slices from specimens. The use of a microtome will be covered in a future entry.

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Filed under: Biology, Microscope