Public speaking involves addressing a large audience formally on a topic of general interest. It lacks the feedback and spontaneity of face-to-face communication due to the physical and psychological distance between the speaker and audience. Effective public speaking requires preparation including knowing the audience, choosing a topic, determining the purpose, collecting supporting materials, outlining the speech, and writing and practicing the delivery. Proper use of body language like posture, gestures, facial expressions and eye contact is important to complement the message during a public speaking presentation.