WEBVTT - How do they get the lead in a wooden pencil?

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<v Speaker 1>Welcome to Brainstuff from house stuff works dot com where

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<v Speaker 1>smart happens. Hi am rc Brain with today's question, how

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<v Speaker 1>do they get the lead in a wooden pencil? Take

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<v Speaker 1>a look at the writing end of a brand new

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<v Speaker 1>wooden pencil before sharpening it. It appears that the wood

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<v Speaker 1>casing is one solid piece. This might lead you to

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<v Speaker 1>believe that pencil makers bore a hole straight down the

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<v Speaker 1>middle of the wood and then slide in a rod

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<v Speaker 1>of lead. Although early pencils were constructed that way, it's

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<v Speaker 1>not how most wooden pencils are mass produced today. More

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<v Speaker 1>than fourteen billion pencils are produced in the world every year,

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<v Speaker 1>enough to circle the Earth sixty two times. Before discussing

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<v Speaker 1>how the lead is put into the wood casing, let's

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<v Speaker 1>clear up what the lead actually is. Pencil lead is

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<v Speaker 1>not lead at all. It's a combedyation of finely ground

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<v Speaker 1>graphite and clay, mixed with water and pressed together at

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<v Speaker 1>high temperatures into thin rods. We call it lead because

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<v Speaker 1>the Englishman who first discovered graphite believed that they had

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<v Speaker 1>found lad. According to the Cumberland Pencil Museum, in the

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<v Speaker 1>mid sixteenth century, a violent storm knocked over several trees

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<v Speaker 1>in England, uncovering a large deposit of a black substance

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<v Speaker 1>that was first thought to be led. More than two

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<v Speaker 1>hundred years later and English scientists discovered the substance was

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<v Speaker 1>not actually led, but a type of carbon instead. The

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<v Speaker 1>substance was named graphite, after the Greek word meaning to write,

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<v Speaker 1>since that's how people used the substance. Early pencils were

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<v Speaker 1>crude versions of today's standard model. The first pencil was

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<v Speaker 1>a chunk of graphite used by carpenters to make markings

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<v Speaker 1>without denning their materials. This evolved into a graphite chunk

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<v Speaker 1>wrapped in sheepskin, followed by a ring wrap graphite pencil,

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<v Speaker 1>the first pencil with a rod shaped graphite core. To

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<v Speaker 1>use one of these pencils, the writer would have to

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<v Speaker 1>unravel the string as the graphite wore down. The next

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<v Speaker 1>major leap in design was hollowing out a stick of

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<v Speaker 1>cedar and sticking a piece of graphite down the hole,

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<v Speaker 1>an idea often credited to the Italians. The English embraced

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<v Speaker 1>this idea but simplified the manufacturing process considerably. Instead of

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<v Speaker 1>hollowing out a piece of wood, they simply cut a

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<v Speaker 1>groove in the wood. Inserted a piece of graphite and

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<v Speaker 1>broke it off level with the top of the groove.

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<v Speaker 1>Then they glued a small slat on top, encasing the graphite. Today,

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<v Speaker 1>most wooden pencils are mass produced from large blocks of

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<v Speaker 1>cedar cut into slats. A machine cuts eight grooves half

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<v Speaker 1>as deep as the graphite clay rod is thick into

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<v Speaker 1>slats and then places rods in each groove. Once the

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<v Speaker 1>rods are in place, a second groove slat is glued

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<v Speaker 1>on top of the first. When the glue drives, the

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<v Speaker 1>slats are fed through a cutting machine that cuts the

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<v Speaker 1>wood into various shapes and divides the slats into eight

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<v Speaker 1>separate pencils. The seams of the two slats are then

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<v Speaker 1>sanded down and several coats of paint are applied to

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<v Speaker 1>the pencil, giving it the appearance of a single solid structure.

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