My current favorite ball-point pen that I’m using to take trial notes with suddenly went from black ink to gray ink, and then to invisible ink. I examined the clear ink tube through the clear barrel and saw that an air bubble at the bottom, where the ink joins the metal writing tip, is keeping the ink from reaching the writing tip. I don’t know whether this is a hopeless situation. The rest of the ink tube is full so it’s such a waste if I were to give up on this pen and toss it. Is there a way to get the ink to start flowing down again? This isn’t a liquid ink pen so the ink is pretty viscous. And then I suddenly felt very ignorant because I have no idea how a ball point pen works beyond the basics of, the ball rolls based on friction against a surface, ink rolls from inside the tube to the outside and sticks to the surface. How does the ink make its way down the tube? Gravity alone seems unlikely, since the ink doesn’t slosh around when the pen’s put down on its side.

I started scribbling on a piece of scratch paper, trying to somehow create a vacuum effect so that the ink gets drawn down as air leaves the tip with the scribbling. Sometimes it seems to work as I’d get a few seconds of weak gray ink, but then it would disappear again. Re-examining the bottom of the ink tube hopefully, it does appear like the edge of the black ink has touched down onto the top of the metal writing tip, but the air bubble is still present. I’m not sure air can be worked out this way to draw the ink down; maybe only ink can pull its other molecules down, and it doesn’t work when the train of ink is interrupted.

It’s shocking how little we (I?) know about something that’s so pedestrian and ubiquitous.