The term audio-visual may refer to works with both a sound and a visual component, the production or use of such works, or the equipment involved in presenting such works. Sound' is Vibration transmitted through a Solid, Liquid, or Gas; particularly sound means those vibrations composed of Frequencies The visual system is the part of the Nervous system which allows organisms to see. Movies and television shows are examples of audiovisual presentations. A television program (US television programme (UK or television show (U
Business presentations are also usually audio-visual. In a typical presentation, the presenter provides the audio by speaking, and supplements it with a series of images projected onto a screen, either from a slide projector, or from a computer connected to a digital projector using software such as PowerPoint. A slide projector is an opto-mechanical device to view photographic slides. A video projector takes a Video signal and projects the corresponding image on a Projection screen using a lens system Microsoft PowerPoint is a proprietary Presentation program developed by Microsoft.