The ballpoint pen has a hollow body in which an ink refill is inserted. The tip of the refill has a tiny ball made of brass, steel, or tungsten carbide, a part of which is in contact with the ink. The pen derives its name from this tiny metallic ball. As we write on paper, the side of the ball which is in contact with the ink touches the paper and leaves an ink impression. As the ball is fitted into a socket it can rotate freely as the pen slides over the paper enabling us to write smoothly. Most ballpoint pens depend on gravity to pull the thick ink to the ball. That is why it is difficult to write with a ballpoint pen when its point is higher than its bottom.
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