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The Science Behind Microscopic Food Art

by Katherine J. Dickinson

If you mix science, art and food, you are bound to come up with something interesting (and tasty). But who knew it could also be so stunning?



Artist Caren Alpert has united these disciplines in her series "terra cibbus," a collection of microscopic pictures of food. From Brussels spouts to lifesavers, her subjects are quite diverse. Each picture, however, allows the viewer to see the subject in a way they haven't seen it before. 



AlpertEM10.jpgBelieve it or not, this is a pineapple leaf.



In order to achieve this feat, Alpert used a scanning electron microscope (SEM) to take her pictures. This microscope works by first shooting a beam of electrons at, say, a fortune cookie. The beam knocks other electrons off the surface of the cookie, and the microscope detects the displaced electrons. It then uses the information to form an image.



One of the ways that a SEM is different from a light microscope is that it uses electrons instead of light to create images. Because they are not limited by the comparatively small wavelength of light, electron microscopes can magnify objects up to two million times while light microscopes can only magnify objects a couple thousand times.



Another property that distinguishes the SEM is its ability to produce a 3D image of an object. Traditional light microscopes and even SEM's sister, the transmission election microscope (TEM), show only the cross-section of an object.



But making 3D images first requires some tricky preparation. Because electrons don't travel well through air, the sample must be viewed in a vacuum. In fact, all the water has to be removed from the sample or it will explode. The dehydration process takes several steps, and afterward the whole sample has to be coated in a layer of gold or platinum.



When SEMs were first developed, marketing experts thought there would be very little demand for them. But now, there are many scientists who find SEMs quite necessary for their research.  Dental researchers have used SEMs to study enamel acid etching techniques so that dentists can securely bond things to your teeth.  Other scientists have used them to see exactly how viper venom damages living tissue.

f3t0191.jpg

SEM picture of tooth enamel etched with malic acid. Yikes.



Scientists have even developed a microscope that can take images at the atomic level. The scanning tunneling microscope (STM) works by running along the surface of an object with a probe "like a record player". The probe detects changes in electric current as it skims along a field of atoms and translates these changes into an image.



The STM's images aren't perhaps as pretty or artsy as the SEM pictures, but if you ask me, the simple fact that we can now look at individual atoms is a poetry in itself.

hopg3d-1.jpgGraphite at the atomic level.


Katherine Dickinson is a freelance writer from Minnesota.