Pens work differently from pencils. Read more about pencils here! In this post, we are going to focus on the most common type of pen: the ballpoint pen. All pens use ink, but the cool thing here is how it draws the ink to the tip. In ballpoint pens, there is a small cartridge with pen ink inside. On the tip of the pen, there is a small ball bearing. The ball bearing is typically made out of metal. When you write on paper, the ball bearing spins. As it spins, it actually draws ink from the cartridge and dispenses it evenly on the paper! The ink also dries very fast, so it does not smear. That is how pens work!