Nearly every person in the world will, at one point in their life, use a pen to record, solve of draw something on paper. However, no one stops to think how and why this luxury occurs. How does ink come out of the pen when writing but not while just sitting there? A few main factors determine the flow rate of the ink: the pulling power of the pores of the paper, the pulling power of the pen and the surface tension of the ink. The pores of the paper act like little mini hands that grab on to the surface of the ink at the tip of the pen; rougher paper will pull out ink more quickly, while smooth surfaces struggle to pull out ink. Then, due to the surface tension of the ink, as some of the ink is pulled out, more comes with it. When the pen is not writing, there is nothing to pull the ink out so no ink flows out of the tip of the pen. Also, when the pen is moving, another factor that contributes to ink flow is the speed of the pen: when its moving faster, ink flows out at a faster rate. Now, when ever you write something, you will think about how you are actually making words.