When Does Light Not Go in a Straight Line?

Light does not go in a straight line when it is reflected, refracted, diffracted, or scattered. Normally, light travels in a straight line in a uniform medium like air or vacuum. But under certain conditions, the path of light bends or changes direction. This happens due to interactions with surfaces or different mediums.

Situations Where Light Does Not Travel Straight

• Reflection: Light bounces back when it hits a shiny surface like a mirror.
• Refraction: Light bends when it passes from one medium to another, like from air to water.
• Diffraction: Light bends around the edges of small obstacles or slits.
• Scattering: Light spreads in different directions when it hits tiny particles, such as in the atmosphere.

Examples

• A straw appears bent in a glass of water (refraction).
• Rainbow colors appear in the sky after rain (dispersion and refraction).
• Blue color of the sky is due to scattering of sunlight.
• Light bends around the edges of a narrow slit in experiments (diffraction).