Refraction of Light

Refraction is the bending of light as it passes between materials of different optical densities.

Key points:

• Light changes speed when entering a new medium, causing it to change direction
• Refraction occurs at the boundary between two materials, e.g. air and glass
• The amount of refraction depends on the difference in optical density between the materials

Vocabulary:

• Incident ray: The incoming light ray
• Refracted ray: The light ray after it has been bent by refraction

Example: A straw in a glass of water appears bent due to refraction of light between air and water.

Refraction explains various optical phenomena like the apparent bending of objects partially submerged in water.

What is Light?

Light is a form of energy that travels in waves at extremely high speeds.

Key points:

• Light is produced by sources like the Sun and light bulbs
• It travels in straight lines at 300,000,000 meters per second
• Light carries energy and can be converted to other forms like electrical or chemical energy

Highlight: Light travels much faster than sound.

Example: Solar cells convert light energy to electrical energy, while plants convert it to chemical energy through photosynthesis.

Vocabulary:

• Luminous objects: Give off their own light (e.g. light bulb)
• Non-luminous objects: Do not produce light, only reflect it (e.g. comb)

The human eye detects light directly from luminous objects or light reflected off non-luminous objects. Understanding how light travels and interacts with materials is key to explaining vision and optical phenomena.