Is the lead in the pencil really poisonous?

The lead core of a pencil is mainly composed of graphite and clay. According to national standards, pencils are divided into 18 models according to graphite concentration. The early pencils contained lead, but now the main components of pencil refills used by people are graphite and binder, and lead is no longer contained, which is harmless to human body. But the paint on the outside of the pencil contains lead, so students who like pencils should remember not to contain pencils. This habit must be changed.

At present, in the standardized examination in China, computers can only read pencil handwriting with lead concentration of 2B. Too thick or too light will lead to computer reading failure or error. Pencil lead can unlock a lock because pencil lead contains graphite, which is lubricated, and pencil lead can lubricate a rusty lock.

Graphite has a high melting point. As a lubricant, it is especially suitable for machines working at high temperature. At high temperature, general engine oil will decompose, however, graphite is very stable and continues to play a lubricating role. Graphite is a scaly solid with metallic luster, which is composed of carbon. Its structure is very stable, and nothing in the human body can destroy it, so pencil lead is nontoxic.

As the main component of pencil is graphite, which is a conductor, pencil lead can conduct electricity. However, pencil lead is not very conductive. Because of the atomic structure of graphite, it can only conduct electricity in two-dimensional space, that is, it conducts electricity between two points in the same plane, but it does not conduct electricity between the upper and lower surfaces of the plane.