The thesis/portfolio/project defense will be your opportunity to defend your work before your committee and others.
The first part of your defense (which includes your presentation and questions from the audience/faculty) is public, which means that anyone may attend.
The second part of the defense (which includes the tougher questions from your committee) will occur between just you and the committee.
Expect at least an hour but no more than an hour and a half for the defense.
Every semester, the Graduate College will announce the final date. Keep in mind that you must place a final draft (i.e. the version that you will defend) of your thesis/portfolio/project on display in the department office at least ten working days before you are scheduled to defend.
Know that you will need to be registered for at least one thesis/portfolio/project credit during the semester in which you intend to graduate.