lyijykynään

Lyijykynä, often referred to as a pencil in English, is a writing and drawing tool. Its defining characteristic is the use of a graphite core, not lead, as the marking material. This graphite core is encased in a protective casing, typically made of wood. The graphite is a form of carbon that is soft and brittle, making it suitable for leaving a mark on paper when rubbed. The hardness of the graphite core is varied by mixing it with clay in different proportions, resulting in a spectrum of hardness grades, from very soft (B grades) to very hard (H grades). These grades are usually indicated by markings on the pencil itself.

When a lyijykynä is used, small particles of graphite are abraded from the core and adhere to the surface of the paper. This process is reversible to some extent, as the marks can be removed using an eraser, which typically works by friction or by the adhesive properties of the eraser material. Lyijykynät are widely used in education for writing, drawing, and sketching due to their versatility, affordability, and erasability. They are also employed by artists, architects, engineers, and in various other professions where precise or erasable markings are required. The sharpening process is usually done with a pencil sharpener to expose a fresh point of the graphite core.