scientist with beakers
If you thought the nanometer was small, you didn’t find the angstrom, but that’s probably because it preceded the nanometer. Named for the Swedish spectroscopist and physicist Anders Angstrom (1814-1874), the angstrom is a legacy unit of measurement equal to one ten-billionth of a meter, or 1/10,000,000,000 of 3.28 feet. Put another way, it would take 245 million angstroms to equal an inch, 10 million angstroms to equal a millimeter, or 10,000 angstroms to equal a micron. And now you’ve guessed that a nanometer being one billionth of a meter, it takes 10 angstroms to equal one nanometer.
In 1868, Anders Angstrom was studying solar radiation and compiled an electromagnetic energy chart that measures light waves in increments of one ten-millionth of a millimeter. It was this unit of measurement that became known as the angstrom. Although the angstrom was replaced by the nanometer as the unit of choice, it was traditionally used to measure very small objects such as atoms and chemical bonds, as well as light waves and the visible light spectrum.
For humans, visible light includes wavelengths between deep violet and deep red. Violet light, for example, measures in the 4,000 angstrom range, while dark red is closer to 7,000 angstroms. Wavelengths at 5500 angstroms (just in between the two extremes) would be yellow light, in the center of the visible light spectrum. Today, however, the visible light spectrum is most often expressed in a range from 400 to 700 nanometers (nm).
To offer some real-world examples of the angstrom, a very fine human hair of just 50 microns would be 500,000 angstroms thick. A sheet of paper is about a million angstroms thick, and a credit card is about 8 million angstroms thick.
Although the angstrom has served its purpose and is still used in some technical fields, as early as 1978 the International Committee for Weights and Measures called for the withdrawal of this unit of measurement, asking scientists to refrain from applying the angstrom to new applications or fields. .where it was not yet in use. The American National Standard for Metric Practice also discouraged its use, and today the angstrom is considered obsolete.