The KISS philosophy

As you may know, KISS is an acronym for ``Keep It Simple, Stupid." It's a general design philosophy. Part of physics is determining appropriate models for physical phenomena. I want you to learn that the simplest model, which isn't TOO simple, is the best.

For example, A good model for the trajectory of a baseball does NOT include the gravitational effects of Venus (but it DOES include the gravitational effects of the Earth)!

Why? Why not include Venus? A couple of reasons:

• The effects of Venus are very, very small in comparison with the Earth.
• We may not have the Earth effects characterized to enough significant figures to make the Venus effects recognizable.
• The added complexity of the model interferes with our understanding of the fundamental mechanisms responsible for changing the trajectory of the baseball.

A given projectile motion model might leave out air friction. The model could be applied to obtain the trajectory of a shot. However, it would be a ``too simple" model if it were applied to the curvature of a ``curve ball" thrown by a baseball pitcher because air friction is the reason the ball curves! This could be shown by playing baseball inside a vacuum! (It wouldn't curve).