This lecture introduces students to the fundamental concepts of light and sound. It explores the different sources of light, distinguishing between natural sources like the sun, stars, and fireflies, and artificial sources such as bulbs, candles, and LED lights. Students learn that light travels in a straight line, demonstrated by simple experiments using aligned cardboards and a candle flame.

The chapter further investigates luminous objects, which produce their own light, and non-luminous objects, which are visible only when light reflects off them. It explains the difference between transparent (allow all light to pass), translucent (allow some light but not clear images), and opaque objects (block all light).

Students understand how shadows are formed when an opaque object blocks light, and how the size and shape of shadows depend on the position of the object relative to the light source. The chapter also highlights how shiny surfaces reflect more light than dull ones, making them better reflectors.