MadSci Network: Science History

Re: Why did people used to lick the tip of their pencil before they wrote?

Date: Mon Nov 1 17:55:07 1999
Posted By: Rhonda E. Lowe, Undergraduate, Biology & graduate science education
Area of science: Science History
ID: 940847762.Sh

Hi Jim Brennan--

To answer your two questions:

(1) I have searched quite a lot on the Internet to try to find out why people licked the tip of the pencil before writing. In all my searching, I can tell you that this may be one of those questions with an "I don't know" answer. I haven't found any information that gives a reason for this, BUT I did contact a company that sells pencil products. I posed your question to them when I was having no luck with my searches."Everything You Ever Wanted to Know about Pencil Lead" provided some good information. Their response to me was that perhaps licking the pencil was a "habit" for some people akin to a nervous habit that may have helped the person to better concentrate or think regarding whatever the person was going to write down. That sounded pretty reasonable; however, the company's researcher said that they could find no basic reason why this was done. Outside of this, it seems that noone is really sure why some people licked the tip of the pencil prior to writing.

(2) Now, as it relates to the lead poisoning question, actually I learned a lot in researching for your two questions. Don't worry about getting lead posioning from licking the tip of the pencil or getting any of the lead shavings on your hands because actually the center of the pencil, called the writing core, is made of a nontoxic mineral ore known as graphite! Graphite is a form of carbon and is NOT dangerous to your health and it will NOT cause lead poisoning. This may be one of the BIGGEST misconceptions; but, it is understandable with the emphasis on a cleaner, safer, more natural environment. Graphite came into use during the 16th century where a large graphite deposit was discoverd in England. The mineral is a black mineral and supposedly someone walked by and noticed the black mineral clinging to the roots of a fallen tree. This graphite then became known as "plumbago" or "blacklead." Hence, this is the reason why the "lead" in the pencil, which is the writing core, is still known as "pencil lead." This nontoxic material left a darkish mark so artists, writers, and others began using it. In 1821, Charles Dunbar discovered a graphite deposit in the New England area of the northeastern United States, and because this mineral was of such a high quality, the graphite was introduced into the pencils in this country and it was known as the pencil lead. As a matter of fact, the "lead" in pencils of today are often made of a combination of graphite and clay. If the ratio or amount of graphite to clay is varied, then pencil makers can adjust the "hardness" of the writing core or pencil lead. So, what this means is that we have #1, #2, or #3 pencils. As the number gets higher, then the harder the writing core.

Well Jim Brennan, I hope this helps you out some and I only wish that I could have found a REAL reason, other than "I don't know," for why people licked the tip of the pencil before writing. Thanks for your questions, and think of some more!!---Rhonda Lowe

Admin note:
Dian Beydoun adds the following:

Having had first hand experience using that type of pencil ,the answer to the question is that in the old days the filaments used in pencils were made of different material than today's graphite which is charcoal colored and its particles separate easily on friction with the paper surface leaving clear marks. The old material did not leave much of a mark on the paper due to its high density. It was water soluble and if left in a water filled container ,will dissolve completely. On contact with water it changes color from dark charcoal like color to violet blue. In order to leave a clear mark on paper it was necessary to actually moisten the tip of the pencil filament with your saliva ,the resulting product behaved and flowed like ink.

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