Photogenic Molecules

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By Linda | February 16, 2008

The answer to yet another pair of stupefying questions posed by my nine-year-old…

What does a molecule look like?

Molecules have long been represented by ball and stick models that illustrate the number and type of atoms they are made up of and the way these atoms are bonded together. More recently representations of molecules are rendered in 3-D utilizing computer software. Neither of these methods however, accurately portrays what an actual molecule really looks like.

Model of Water Molecule

Can a molecule be photographed?

A molecule cannot be photographed in the conventional way. Photography requires light to capture an image. Since the wavelength of visible light is longer than a molecule is large, the molecule cannot be photographed.

That said, images of a molecules and atoms can and have been produced using a non-optical device called a Scanning Tunneling Microscope (STM).

Image of Cesium and Iodine atoms

Cesium makes a particularly good imaging subject because as far as atoms go, it’s very large. At the molecular level, scientists measure size in nanometers (nm), that’s one billionth of a meter! A Cesium atom measures about 6/10 of a nanometer in diameter. The wavelengths of the optical spectrum range from approximately 400 to 700 nm.