Overview
This lecture explains why objects like a pencil appear bent in water, focusing on the concept of refraction of light.
Refraction of Light
- Refraction of light is the change in direction of light when it passes obliquely from one medium to another.
- The two media involved in this example are air and water.
- Light changes speed and direction as it moves from water (denser medium) to air (rarer medium).
Why Objects Appear Bent in Water
- Light rays from the submerged part of a pencil pass from water to air and get refracted.
- Our eyes receive these refracted rays and trace them backward in a straight line.
- This tracing makes the rays appear to come from a higher position than the actual tip.
- As a result, the pencil (or magic wand) appears bent or displaced at the water’s surface.
Key Terms & Definitions
- Refraction of Light — Change in direction of light as it passes from one medium to another at an angle.
- Medium — A substance (like air or water) through which light travels.
- Refracted Ray — The light ray that has changed direction after passing into a new medium.
Action Items / Next Steps
- Review examples of refraction in daily life (e.g., straw in a glass, swimming pool depth).
- Observe refraction by placing an object partially in water and noting its apparent bend.