How do Ball Point Pens Work?

The science behind our words!

“Can I borrow a pen?” “Hey buddy, do you have something to write with that I could use?” These are phrases that you always here in a classroom or out in the halls in between classes. Students act like vultures to get themselves the necessary writing tools, but they don’t even tale the time to understand how they work. Every day you use a pen to take notes or to sign paperwork, but you often don’t give a second though to understand how your pen even works.

What makes my ball point pen write?” asked no student ever because they were more focused on trying to write down notes, but if someone did take the time to ask, you would get a very interesting answer. Ball point pens are given their name because at the tip of the pen is a small metal ball. Usually, the ball is made out of brass, steel, or tungsten carbide, and the ball is held in place by the socket of the pen. The ball acts as a buffer between the thick ink reservoir and the air, so the ink won’t dry out. Additionally, the ball serves as a mechanism for getting the ink onto the paper.

Although the ball is in the socket tightly, the metal ball still has enough room to roll around. As you write, gravity helps force the ink down onto the ball. As the ball rotates, it transfers the ink onto the paper, and ink print was mastered! So, go ahead and try out these fun activities.

Try It Out!

Activity 1:

Get a ball point pen and a sheet of paper. Try writing “She sells seashells down by the seashore” five times on the underside of a table. Did you notice any changes in the flow of ink?

Activity 2:

Carefully take apart a ball point pen to understand how each piece works. See if you can label each part of a pen.

Simple Ball Point Pen Diagram

Try comparing your answers to this diagram. Maybe your pen has more parts or maybe it has fewer.