What does nano mean? When people use terms like nanoscale, nanometer, and nanoscience what are they talking about? The root word—nano—means “extremely small” or “one billionth”    (10-9). That means a nanometer is one billionth of a meter. So, if you know how big a meter is that helps you understand how very small a nanometer is. It is helpful to understand scale—or how things compare in size.


Consider this.

  • A meter is a little bigger than a yard—about 3.28 feet.
  • A centimeter is 1/100th of a meter. A sugar cube is about a centimeter wide.
  • A millimeter is 1/1000th of a meter. A dime is around one millimeter thick—and so is a paperclip.
  • A micrometer, also called a micron, is one millionth of a meter. Dust mites are usually around 400 microns long and a hair from your head is about 40-50 microns wide.
  • A nanometer is 1,000 times smaller than a micrometer. A sheet of paper is about 100,000 nanometers thick. One inch equals 25,400,000 nanometers.


Things at the nanoscale cannot be viewed with standard microscopes. Special microscopes like Scanning Electron Microscopes (SEM) are required to see things that tiny. The images in the Human Body category include objects that are part of or live on our bodies. Every year, people who own scanning electron microscopes from microscope-maker FEI enter their best microscopic images in the FEI Image Contest. The images in this collection are from that contest.


About Scale

Learn how to measure the size of the objects in this collection. Click and drag to move the image in order to see the very bottom—or download the image—and note the scale bar. (One image—the human hair—does not have a scale bar, but the size of the image is provided in the descriptive information.) This bar will be different for every image. The scale is noted most often in micrometers (μm), but sometimes in millimeters (mm) or nanometers (nm). These scale bars are used much like the bar scales on maps—where one inch might equal 100 miles, for example. Use a piece of paper, a ruler, or other measuring device to determine the size of the object according to the scale on the image. Note that the scale might be indicated in millimeters, micrometers, or nanometers. Then list the images on paper, or place downloaded images in order, according to size—from largest to smallest.


About Electron Microscope Images

All images taken with electron microscopes are black and white because of the absence of light in the process. Color is added in post-processing phases.

When enlarging or cropping images with scale bars, such as the microscopic images in this collection, be sure to maintain the original aspect ratio of the image—ensuring that everything in the image is reduced or enlarged proportionally.

  • Researchers seeking to understand the fundamentals of properties at the nanoscale call their work nanoscience; those focused on effective use of the properties call their work nanoengineering.
  • Things behave differently at the nanoscale. They might be stronger, more reactive, or behave differently to light. These differences make it possible for scientists to create new products using nanotechnology.
  • The word nanotechnology comes from the Greek word nanos (dwarf) and describes the work that scientists and engineers undertake to manipulate these minute objects to make useful products.
  • Bright red sunsets are caused by nanoparticles in the atmosphere, much of which come from volcanic eruptions.

metric unit of measurement, equal to about .34 inch.


a unit of length equal to one millionth of a meter—also called micron.


a unit of length equal to 11000 meter.


(nm) billionth of a meter.


length scale whose relevant unit of measurement is the nanometer (nm), or a billionth of a meter. Also called the nanoscopic scale.


distinctive relative size, extent, or degree.

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This material is based in part upon work supported by the National Science Foundation under Grant No. DRL-0840250. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.