A Brief History of Pencil Lead (VIDEO)



Courtesy of the YouTube channel Skunk Bear



You probably know that pencil lead isn’t actually lead It’s a mineral called graphite A lattice of pure carbon atoms. To get to this graphite’s origin you can’t just go back to a pencil factory. We have to go all the way back to the start of the universe Back then there wasn’t any carbon just a hot soup of high-energy particles. They cooled, forming hydrogen and helium In the bellies of dying stars, helium atoms were smashed together. Carbon was born! When these stars exploded … the universe was seeded with this versatile new element. Here, on our planet, all living things are built with carbon atoms. That’s why Carl Sagan was fond of saying, “We’re made of star stuff”. So how did this carbon get into pencils? Living things died, and some of them piled up in lake beds. Over millions of years their carbon atoms rearranged. Depending on pressure and temperature, sometimes they became oil or coal and sometimes they became graphite.

A storm in the 16th century England revealed one of these deposits and local shepherds used the stuff to mark their sheep. Graphite is a bunch of flat sheets of carbon atoms stacked on top of each other the bonds between those sheets are weak so they slide apart really easily, and when you drag a piece of graphite across a surface like a piece of paper or a sheep it leaves those sheets behind. Graphite looked and acted a lot like lead so that’s what people call it In the 1800s a thoughtful young man named Henry David Thoreau found that mixing graphite with clay made it harder. Pencils with clayier graphite made lighter marks.  And Thoreau’s proud father introduced a numbering system.

Soon pencils were being mass-produced in factories like the General Pencil Company. They’ve been making pencils here for over a century. It all starts in the Lead Department. Graphite and clay are mixed in giant drums. This machine shapes the clay into rods. These are the cores of future pencils. They’re baked to remove moisture. In the Grooving Department the cores are placed between wood panels. Two panels are glued together, set to dry, and then cut into individual pencils. In the Polishing Department the pencils get layer upon layer of paint. And the final touch?

And that’s how pencil lead is made!



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