**Learning objectives**

- Develop an intuitive understanding of flux through a surface
- Distinguish between a flux and a flux density
- Motivating example is mass flux: where
- is an oriented surface in 3-space
- is a vector field in 3-space, units

- Compute flux integrals geometrically
- when vector field is tangent to the surface
- when vector field is orthogonal to the surface and of constant magnitude on the surface

- Compute some flux integrals analytically using surface parameterizations

**Before class**

- Read Hughes-Hallett section 19.1, 19.2
- Ponder Hughes-Hallett problems: 19.1: 1, 2, 10, 11, 37, 38; 19.2: 5, 13, 21.

**In class**