Abstract Optical observations on the free surface of superfluid 3He-B have been made using an interferometer. The change in viscosity was seen at the superfluid transition, and the fountain effect in 3He-B was observed directly. The equilibrium average density of vortices was ascertained by looking at the reflection of light from the free surface of the rotating superfluid. Heat leaks due to illumination were investigated. Our results will be illustrated by a video film showing the similarities and differences between the superfluid and the normal liquid.