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YouTube, it's Cram. How does a ballpoint pen work? It seems simple right? You start writing
and ink comes out, easy as that. Well, its a bit more complicated than you think. Have
you ever wondered why all the ink doesn't come out at once? Or why it doesn't spill
when you don't use it? Well, the answer lies in the name itself. A ballpoint pen has a
small ball in the tip, or point. This is typically made of a very hard metal, like tungsten carbide.
This ball is fairly secure, but when you write with pressure, the ball rolls. The ink is
stored in a narrow cartridge, which leads up to this ball so when the ball rolls ink
comes out, because there is enough space beside the ball, and the ink adheres, or sticks to
the ball just a little bit, and so the ball applies the ink to the paper. So how come
it doesn't spill through these cracks otherwise? It is because of surface tension and cohesion.
Ink is typically very cohesive and has a lot of surface tension, so it will stay together
unless it is forced apart, and a small ball is enough to do just that. I hope you enjoyed
this quick explanation! Subscribe to stay up to date on all my new videos, and until
next time, Cram out.