The importance of sound in a film:

• What is sound? 

Sound is a vibration that propagates as a typically audible wave (what you hear). 

• What is a soundscape?

A piece of music considered in terms of its component sounds.

• What is sound design? 

The process of specifying audio elements - includes film making, radio, TV production, etc. 

• What is "suspending disbelief"?

A willingness to suspend ones critical faculties and to believe the unbelievable.

• Throughout many films the main soundtrack is comprised of three essential ingredients: 

1. The human voice
2. Sound effects 
3. Music