Major objective of this lecture is to present on Light and Sound. In this lecture briefly describe on: Properties of light; Reflection; Colours; Refraction; Properties of sound and Hearing. Light travels much faster than sound. For example: Thunder and lightning start at the same time, but we will see the lightning first. When a starting pistol is fired we see the smoke first and then hear the bang. We see things because they reflect light into our eyes. Shadows are formed when light is blocked by an object.