True or false: You can get lead poisoning if you’re stuck with a lead pencil.
False. Lead pencils contain graphite (a form of carbon), not lead. In fact, contrary to what many people believe, lead pencils never were made with lead.
The ancient Romans used a writing device called a stylus. This was similar to the modern stylus used with smartphones and tablets, except it was bigger and made from lead. Instead of inputting data electronically, the Roman stylus was used to etch markings into wax tablets or to leave dark marks on papyrus, a plant-based substance that was used the way we use paper today.
In the early 1500s, a vast deposit of graphite was discovered in Cumbria, England. This deposit not only was enormous, but it also consisted of the purest and most solid graphite ever found.
At the time of the Cumbria discovery, pencils were not made the way they are today. Instead, blocks of graphite were sawed into sticks to be used as writing implements. (They must have looked like fat, black crayons, minus the label.) The tips were probably sharpened with knives the way people whittle sticks.
Because chemistry was a young science at the time, people thought graphite was a form of lead; hence the name given to pencils.
The next step in the evolution of the pencil came in the late 1500s, when graphite rods were placed inside wood sleeves that were glued together. This made pencils easier to use.
Pencils got another makeover in 1790, when someone discovered that you could vary the hardness of the lead by mixing powdered graphite with clay and firing (heating) it in a kiln. Although today’s machines are more sophisticated, this is basically the way pencils are still made.
The more clay that is added to powdered graphite, the harder the lead is. Over time, the No. 2 pencil became the preferred writing tool for school-age kids. I suspect this was because it had the perfect blend of hardness (so it wouldn’t break easily) and blackness (for readability), but the lead was soft enough to be erasable.
Here are some more cool facts about pencils:
• Carpenter pencils are usually oval, rectangular or octagonal (that’s eight sides) instead of round or hexagonal (six sides) like the pencils used at school. This makes it less likely that the pencils will roll away while the carpenter is working.
• Most pencils made in the United States are painted yellow. In other parts of the world, they are green, blue, black or red.
• Erasers were not put on the ends of pencils until 1858.
Bonus Fact: In the past, people may have gotten lead poisoning from pencils, but it was the paint, not the graphite, that did it. Lead was outlawed in the United States as an ingredient in paint in 1978. If someone chewed a pencil before this ban went into effect, he could have been exposed to lead. So if you find an old pencil in your grandfather’s attic, don’t bite it!
Bennett is a Washington pediatrician. His Web site, www.howardjbennett.com,includes past KidsPost articles and other cool stuff.