Ballpoint pens are a type of ink pen with a rolling ball at the tip. The ball can usually be between 0.5-1 mm in diameter. The ink in a ballpoint pen is viscid and dries quickly. Because the ball is rolling, you get a nice floating feel when writing. The ink used in ballpoint pens is inspired by the ink used in newspaper prints. Around the 1940s, people started to look for solutions to using the same type of ink in pens as where used in newpaper printing. The problem was that the ink used for the newspapers was too sluggish for a common tip. Finally, a solution was found, where the tip of the pen became a rolling bullet and the pen started to be sold to the general public around the 1950s.