Electron Microscope Mystery 1

Before I became a federal funder, I ran a beautiful environmental scanning electron microscope (E-SEM). Unlike the binocular microscope you probably peered into as a student, an SEM uses electrons, not light, to produce an image. Because electrons are so tiny, you can see things at a much higher magnification than you can with light.

Other reasons electron microscopes are cool include 1) things closer to the beam appear lighter, and things further, darker (as though they’re in ‘shadow’) giving the appearance of 3-dimensionality, and 2) materials made of heavier elements have a higher contrast (and appear brighter) than materials made of lighter elements (which appear darker). For example, if you looked at an object made of aluminum (Al) and lead (Pb) stripes, the Pb lines would be brighter than the Al stripes.

For decades, electron microscopy required that samples be very small, polished flat, and coated in something conductive, like gold or carbon. An ‘environmental’ SEM, however, has a huge chamber, within which you can put a range of materials of varying shapes:

Left photo from John Pinizzotto: http://wildcatphysics.blogspot.com/ .... Right photo from/of me.

When I met my first E-SEM over 4 years ago, I needed to see what materials and shapes fit in the chamber, and which responded well enough to the beam to get good images. So like any good scientist, I experimented. These experiments resulted in a collection of electron microscope images of everyday objects, and I quickly realized the joy that comes with making friends guess what the objects were, based on high-magnification electron images. I ran this series on Flickr for a while, years back, but thought I would resume the fun here.

Thus, I give you #1 in the Electron Microscope Mystery series. The image below is about 70 microns across (0.007 cm). Can anyone guess what this is? I’ll update later in the day with a wider field of view.

Update at 1:20p: Added two views, each zoomed out a bit more (the width of the last is about 0.7mm wide…

Update at 2:40p: It’s been solved! These are ink particles pressed into paper fibers. The sort of pointed shape you see is the point of an upside-down letter M:


11 Comments on “Electron Microscope Mystery 1”

  1. Jennifer says:

    One friend on IM guessed ‘rust,’ and I can tell you it is not!

  2. Jessica Ball says:

    Hmm…Looks a bit like velcro in the last new photo, but not quite loose enough of a weave. It also reminds me of cantaloupe 🙂

  3. Jennifer says:

    Well, there were a ton of excellent guesses on Twitter:
    – pancake
    – dental floss
    – fiber or fabric
    – “something edible”
    to which I said it is edible only if you’re trying to keep a secret (as in, a note you eat to dispose of the evidence!)
    And the closest one was wrapping paper, guessed by @missyleone 🙂 Nice job!

  4. BWKP says:

    So is your old E-SEM chamber large enough to handle a Smith & Clarkson pancake? I would donate/sacrifice one if you still had access (meaning, I would eat a plate full of pancakes until I was satisfied, and then buy another pancake and rush it to the E-SEM before I was tempted to finish off another whole pancake).

    • Jennifer says:

      It is totally large enough for an S&C pancake! See that big piece of art I’m sticking in there, above? Perhaps I should schedule some beam time…

  5. […] time for the Third in my series of electron microscope mysteries (click to see One and […]

  6. […] back with another electron microscope mystery… Can you guess what this is? The image is 1 mm […]

  7. […] my programs at NSF, so I have been a major slacker here at FS. To make up for it, I bring you a new electron microscope mystery! The field of view here is 6mm. What do you think it […]

  8. Laura says:

    Wow, marvelous blog layout! How long have you been blogging for?
    you made blogging look easy. The overall look of your web site is magnificent, as well as the

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