Light, Shadows and Reflections

Transparent: light passes through completely (clear glass, water). You can see clearly through it. Translucent: some light passes, but scattered (frosted glass, oiled paper, thin cloth). Blurry vision through it. Opaque: no light passes (wood, metal, stone). Shadow formed behind it.

Shadow forms when opaque object blocks light. Shadow is always on opposite side from light source. Bigger/closer object = larger shadow. Farther object = smaller shadow. Shadow shape shows silhouette of object. Shadows show direction of light source.

A dark box with a tiny pinhole on one side. Light rays from object pass through pinhole and form an INVERTED, diminished image on the screen opposite. Proves light travels in straight lines. The image is inverted (upside down) because rays from top of object go to bottom of screen.

Reflection: bouncing back of light from a surface. Regular (specular) reflection: smooth surface (mirror) → clear image. Irregular (diffuse) reflection: rough surface → no clear image. Plane mirror forms virtual, erect (upright), same size, laterally inverted image. Lateral inversion: left appears as right in mirror.