Nanometers: Definition & Symbol

Instructor: Damien Howard

Damien has a master's degree in physics and has taught physics lab to college students.

Discover what exactly is meant by the term 'nano'. Then learn exactly how small nanometer-sized objects are and some examples of what exists at that size scale, both naturally and artificially created.

What Exactly does Nano Mean?

People have been throwing around the prefix 'nano' for a while not knowing what it really means. You can probably trace this phenomenon back to the first release of the iPod nano and the incredible success it had. As more products came out using the prefix nano, people came to associate it with anything small. However nano is not just a synonym for small. It has a very specific size associated with it. Nano is a metric prefix that stands for one billionth. In the sciences, you most often see the prefix associated with meters, or nanometers. A nanometer is a unit measuring one billionth of a meter in length. In the international system of units, more commonly referred to as SI units, the nanometer is represented by the symbol 'nm.' In scientific notation, one nanometer can be written as 1 x 10^-9 meters.

The Nanoscopic Scale

Now that you know that a nanometer is one billionth of a meter, you probably still don't have a good idea of exactly how small that is. A billionth of anything is a hard concept to try and visualize. We can use a couple of examples using objects you might be familiar with to get a better grasp on the size of a nanometer.

Let's imagine we are making a scale model, and in our scale model we have a marble. The diameter of that marble represents a single nanometer. We also want to have another sphere that represents a meter in diameter so we can visually compare the two. Unfortunately our scale model is going to be quite hard to build, because if the diameter of a marble represents one nanometer, the sphere that represents one meter would have to be the size of the Earth. If you're having a little trouble visualizing this because you aren't familiar with meters and the metric system, let's instead quickly look at an inch on a standard ruler. Inside every inch on a ruler there are 15 little markings that break it down from 1/16th an inch all the way through 15/16ths an inch. Say instead of breaking the inch measurements into 16ths we wanted to break it down into nanometers. Then instead of 15 markings on the inside of that inch measurement you would need about 25.4 million markings.

Image of a Rule with Inch Markings
ruler image

Hopefully you've got a better idea of how small a nanometer is now. Objects that exist at this size range are so tiny that they cannot be seen by optical microscopes. They are considered to be on the nanoscopic scale which consists of the size ranges between 1 and 100 nanometers. A couple examples of objects on the nanoscopic scale would be viruses and deoxyribonucleic acid, a.k.a. DNA. Viruses fall between 30 and 50 nanometers in size, and DNA have a diameter of about 2.5 nanometers. Objects like these on the nanoscopic scale are some of the smallest you can get before heading into the very building blocks of our universe in the atomic scale with molecules and individual atoms.

Objects Above, Below, and on the Nanoscopic Scale
nanoscopic scale chart

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