# Vector Calculus: Question about the origin of the term 'divergence'

1. Sep 10, 2009

### Vectronix

Why is the divergence operation called the 'divergence?' What is the significance of this operation on a vector-valued function? And what about "the curl?" The curl seems self-explanatory (at least it does in electrodynamics), but I need someone to expound on 'the curl' as well.

2. Sep 10, 2009

### waht

The divergence gives you flux density of a vector field. If it's positive in a region then the vector field spreads outward from itself. That's why it's called divergence.

And the curl is a sort of rotational density of a vector field. Curl is a vector whose magnitude is proportional to the strength of rotation of the vector field. Hence it's called curl.

3. Sep 12, 2009

### tiny-tim

Hi waht! Hi Vectronix!

And, conversely, if the divergence is negative, then the field lines converge.

In particular, you get divergence round sources, and convergence round sinks.