Ballpoint pen

People say the pen is mightier than the sword. Physics plays a major role in using a pen as a tool for writing. The design of the ball pen explains the physics facts in everyday life. When you use a ballpoint pen, it involves principles of fluid dynamics and friction. There is a small spherical point object at the tip of the ball pen. When you apply pressure to the pen and move it across the paper, the ball rotates and rolls.

As it rolls, it picks up ink from the refill, which is a small tube filled with ink inside the pen. Because of the gravitational effect, the ink flows through the ball and then onto the paper. This mechanism ensures a smooth flow of ink and allows you to write or draw with precision.