Why is there
no lead in
a lead pencil?
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The full narration of the video.
Growing up, we were told: don't chew your pencil, you'll get lead poisoning. But sharpen one open, and there isn't a speck of lead inside. So why is it called a lead pencil? Let's follow that black core back four or five hundred years. In northern England there's a valley called Borrowdale. Around the 1560s, locals dug a strange black stone out of the hillside.
Dark grey, shiny, slippery to the touch, and drag it across something and it leaves a grey line. Shepherds used it to mark their sheep. That grey line reminded people of something old. Europeans had long used sticks of lead to rule lines on paper, and lead leaves a grey line too. Looks alike, writes alike, so everyone decided: this must be a kind of lead ore. They called it black lead.
Black lead drew a far darker line than real lead. People cut it into thin sticks and wrapped them in wood, and the pencil was born. How precious was this black stone? In 1752, Britain's Parliament passed a law: steal it, and you could go to prison, or be shipped off to a penal colony. But was it really lead? It took two hundred years for someone to properly check.
In 1779, the Swedish chemist Carl Scheele put it to the test. He burned it, and what came out was carbon dioxide. Lead can't burn into carbon dioxide. It wasn't lead at all. It was carbon, the same stuff as charcoal, and diamond. Ten years later, the German geologist Abraham Werner renamed it, after the Greek word for writing: graphite. In Chinese it's 'ink stone', a stone that writes.
The truth was out, but the name stuck. English still calls the core 'lead', German calls it a 'lead stick', and Chinese calls it a 'lead pen'. In 1795, a Frenchman named Conté ground graphite into powder, mixed in clay, and baked it hard. More clay, a harder, paler core. More graphite, a softer, darker one. So, back to the start: the core is graphite and clay, no lead. But to be fair, until the mid-twentieth century, the paint on some pencils really did contain lead.
Today there are standards, in China and abroad, limiting lead in pencil paint. Chewing the core won't give you lead poisoning, but still, don't. Wood and paint aren't snacks. Once a name catches on, it's hard to change, even when it turns out wrong. Like how a whale isn't a fish, but in Chinese it's still a 'whale-fish'. What other name have you seen that's been wrong all along?
Split one open: no lead at all
As kids we were told:
don't chew your pencil, you'll get lead poisoning.
But a pencil core is graphite and clay. There's not a speck of lead in it, and there never was. So why the name? We have to go back four or five hundred years.
A black stone from a valley
In Borrowdale, a valley in northern England, locals around the 1560s dug up a black stone: dark grey, shiny, slippery, and it left a grey line on whatever it touched.
Shepherds used it to mark their sheep.
It looked like lead, so they called it “black lead”
Europeans had long ruled lines on paper with sticks of lead, and lead leaves a grey line too. It looked alike and wrote alike, so people decided it was a kind of lead ore and called it “black lead”.
Black lead drew a far darker line than real lead. Cut into thin sticks and wrapped in wood, it became the pencil.
Fire tells the truth
Was it really lead? It took two centuries for someone to check. In 1779, the Swedish chemist Carl Scheele burned it, and it turned into carbon dioxide.
Lead can't burn into carbon dioxide. It was carbon, the same stuff as charcoal and diamond.
Ten years later, the German geologist Abraham Werner named it graphite, from the Greek word for “to write”. In Chinese it's called “ink stone”: a stone that writes.
The truth came out. The name stayed.
In 1795, a Frenchman named Conté ground graphite into powder, mixed in clay and baked it hard. Pencil cores are still made this way:
So is chewing a pencil a problem?
The core has no lead. But to be fair: until the mid-20th century, the paint on some pencils really did contain lead.
Today there are standards limiting lead in pencil paint, in China (GB 8771) and elsewhere. Chewing the core won't poison you with lead, but don't: wood and paint aren't snacks.
even wrong ones
Quick check
Pencils contain no lead. So why are they called lead pencils?
The valley's black stone drew grey lines just like lead, so it was called black lead. It turned out to be carbon; the name stayed.
