Tonight, August 2, at 8 p.m. the Martha’s Vineyard Film Society is presenting a film whose subject matter knows no shortage of dedicated believers, angry dissenters, and, perhaps largest of all the constituents, the confused masses in the middle.

The film is called Cape Spin and it aims to chronicle both sides of the debate over the proposal to build wind turbines in Nantucket Sound, also known as Cape Wind.

This screening is being publicized as a sneak preview of the movie. The director Robbie Gemmel will be in attendance to answer questions about the making of the movie and its electrified subject matter. There will also be a panel discussion after the movie regarding Cape Wind and other local wind projects.

The screening takes place at Union Chapel in Oak Bluffs. The cost is $10, or $7 for film society members. Doors open at 7:15 p.m.

For more details, call 508-696-9369.