Shadows and Reflections

Overview

Light travels in straight lines and lets us see objects. This chapter explains how shadows form and how light bounces off surfaces in reflection.

Key concepts

• Light travels in straight lines.
• Opaque objects block light and form shadows.
• Transparent objects let light pass through.
• Reflection is the bouncing back of light from a surface.
• A plane mirror forms a clear image.

Important terms / formulae

• Shadow: dark area where light is blocked.
• Reflection: bouncing of light from a surface.
• Opaque: does not allow light to pass.
• Transparent: allows light to pass through.

Solved example or key process

Hold an opaque ball in sunlight. Because light travels straight and cannot pass through the ball, a dark shadow forms on the ground behind it. Move the ball closer to a wall and the shadow becomes sharper and smaller.

Important questions

1. Why does a shadow form?
2. What is reflection of light?
3. Differentiate between opaque and transparent objects.
4. What kind of image does a plane mirror form?

Quick revision

Light travels in straight lines. Opaque objects form shadows, transparent objects let light through, and shiny surfaces reflect light. A plane mirror gives a clear, upright image.