Were pencils ever really made with lead, or has it been graphite all along?

– Stefan Schetselaar, Gainesville, Va.

Stefan, when I read your question I thought, “I betcha they were once made with lead – say, back before the 1920s. Then makers probably switched to safer stuff because kids kept getting stabbed with pencils.”

Nope.

Many of us did indeed suffer a childhood pencil stab or two – and perhaps a moment of panic, thinking: “Will I die of lead poisoning?!”

But makers say pencils have been made with graphite, a form of carbon, all along. People just didn’t know it was graphite.

Egyptians drew with lead rods. Maybe this is an ancient root of the confusion. But the real story begins about 1500, when a violent storm hit the coal country near Keswick, England. Trees were blown over, and underneath, shepherds found black deposits. They assumed this was a kind of coal. But this stuff wouldn’t burn.

The shepherds discovered that the dark mineral was smudgy, and used it to mark their sheep. Informally, they called it “wad.” But many gave it the name “black lead.”

People around Keswick increasingly used chunks of it to mark, draw and even write with. Locals gradually developed crude pencils. Word spread – eventually to Italy’s arts community. The Italian shipping industry hauled “black lead” to Italy, where artists used it for sketching.

In 1779, Swedish chemist Carl Scheele determined that black lead was a form of carbon. In 1789, German geologist Abraham Werner gave it the name graphite, after the Greek graphein, meaning “to write.”

Today pencil “lead” is a combination of finely ground graphite and clay, mixed with water and pressed together at high temperatures into thin rods.

The number printed on the side of a pencil indicates hardness of the graphite. The higher the number, the harder the graphite core. Because a hard core leaves behind less of the graphite-clay mixture on the paper, it will have a fainter mark. That’s why a standardized test (the scourge of my youth) needed to be taken with the legendary No. 2 pencil. Higher than No. 2 wasn’t dark enough to be read by the test scanner. No. 1 was too smudgy (even though I liked the soft, dark way they wrote).

What are the differences between wasps, hornets and yellow jackets?

– Cozette Stacy Nowak, Fort Mill, S.C.

Cozette, technically, hornets and yellow jackets are wasps, which is a large order of insects.

These are wasp characteristics:

• Two pairs of wings.

• A stinger (only present in females).

• Few or no hairs (unlike bees).

• They’re important in natural bio-control. Almost every pest insect species has a wasp species as a predator or parasite.

Yellow jackets are small black and yellow wasps (though some can be black and white). They live in colonies and build paper nests, often in the ground. They can sting repeatedly in response to nest disturbance.

Hornets are wasps with wide heads and round abdomens. Despite their fierce reputation, they are not as aggressive as yellow jackets.