Researchers at the Canadian Museum of Nature work at an incredible array of scales, from mountain ranges and whales, down to diatoms and atomic structures. At the smaller end of this range, we need microscopes to help us better describe our samples, but even large-scale fields of study can benefit from a close look at the microscale.

One of our most versatile tools is the scanning electron microscope (SEM). By using a very fine beam of electrons that interacts with the sample surface, it allows us to study things that are orders of magnitude smaller than what we can typically see with an optical microscope. This process provides very detailed information about the topography and make-up of the sample.

It is a powerful instrument that is used to learn about all kinds of natural materials from the plant, animal and mineral kingdoms. The pictures below show some of the varied and interesting samples examined by museum researchers using the SEM. Take note of the scale bar in each image to get a better idea of the actual size of the subjects.

A grayscale image of an oval-shaped, 20 x 80 micron diatom.
Diatoms are small algae that live in salt and fresh water. They protect themselves with a shell of silicon dioxide that allows light to pass through. This diatom Neidium rugosum is a new species first described by museum phycologist, Paul Hamilton. It was collected in Wapusk National Park, Manitoba. Image: Paul Hamilton © Canadian Museum of Nature
A grayscale image of a round megaspore 500 microns in diameter.
Botanists Paul Sokoloff and Dan Brunton produced this stunning image of a megaspore of newly described quillwort Isoetes laurentiana. Although some parts look fuzzy, zooming into the image shows the fine structure of the spore. Image: Paul Sokoloff / Dan Brunton © Canadian Museum of Nature
A grayscale image of several light grey, tube-like structures up to 1 micron in diameter and up to 10 microns long on grey cement surface.
Calcium carbonate tubes on a cement surface experimentally exposed to a culture of Geobacillus thermodenitrificans bacteria. These bacteria can live in very calcium-rich solutions and are able to grow a protective shell of calcium carbonate around themselves. These shells are the tube-like structures. Image: Justin Whittaker © University of Ottawa, Earth Sciences.
A grayscale image of numerous tabular crystals of nisnite oriented perpendicular to each other.
Tabular crystals of nisnite, Ni3Sn, a new mineral from Asbestos, Quebec, described by museum mineralogists Ralph Rowe, Joel Grice and Glenn Poirier in 2011. Horizontal width of the image is 150 microns. Image: Glenn Poirier © Canadian Museum of Nature

The SEM excels at imaging small subjects, but surprisingly, it is also very good at imaging relatively large things.

A grayscale image of a scarab beetle.
Scarab beetle Besourenga horacioi collected by museum entomologist François Génier. It is almost 2.5 mm long and 1.5 mm thick. The image is sharp from the top of the carapace to the bottom of its feet, a depth of field that would be difficult to obtain with an optical microscope. Image: François Génier © Canadian Museum of Nature

The SEM can also show us unexpected sides of objects we use in everyday life.

A grayscale image of two light grey, 200- and 400-micron wine crystals on dark grey cork.
Potassium tartrate (wine crystals) on the surface of a cork from a wine bottle. The darker material is the cork made from the bark of a cork oak. The bright features are wine crystals, which are also known as cream of tartar when used in the kitchen. Image: Lucas Grier-Beauregard © Canadian Museum of Nature

Hopefully these images have shown you how important the SEM is to the work of the researchers at the Canadian Museum of Nature. Notice how interesting and beautiful the world is when we are seeing with electrons?