सिसा कलम के बाट बनेको हुन्छ, होला?

पेन्सिलको कोर ग्रेफाइट र माटोको मिश्रणबाट बनेको हुन्छ, जसलाई ठोस लेखन सामग्री बनाउन उच्च तापक्रममा निकालिन्छ। 

The core of a pencil is made up of a mixture of graphite and clay, which is fired at high temperatures to create a solid writing material. The ratio of graphite to clay can vary, leading to different degrees of hardness and blackness of the marks made by the pencil. The graphite provides the black pigment, while the clay gives the pencil its structure and allows it to hold its shape. The graphite and clay mixture is then encased in a cylindrical wooden barrel, which provides a surface for grip and protects the writing core. The eraser on the end of many pencils is usually made of rubber or synthetic rubber materials.