This Is Why You Only See No. 2 Pencils
In all likelihood, if you rummaged through any given school desk in the U.S., the first pencil you'd encounter would be a number two pencil. Here's why.
The United States tends to do its own thing when it comes to categorizing things, and this holds true when it comes to pencils. Pencils are labeled based on graphite hardness, which in turn affects the shade of the mark left behind. Number two pencils are in the middle of the road when it comes to hardness and shade and are ideal for everyday use.
The numeric scale is used by pencil manufacturers in the United States, while international manufacturers tend to use a letter-based scale. The international standard of shade measurement, also known as the HB scale, ranges from 9H on the lightest end of the spectrum to 9xxB on the darkest side of the spectrum.
Pencils below the number two are filled with softer graphite and can create darker markings with a wider range of shades and tend to be preferred by people who work in publishing. Pencils above number two are filled with harder graphite and tend to have lighter markings and are frequently used in draughting pencils, often used by architects and designers. A number two pencil on the numeric scale is roughly equivalent to an HB pencil on the international scale.
Now that you know why you see number two pencils everywhere, learn the nine weird ways that pencils changed the world.
[Source: Pencils.com / Mental Floss]