Light travels in straight lines, separates into a rainbow spectrum through a prism, bounces off mirrors, bends when it enters glass — and your eye sees all of it.
Light is a form of energy that is emitted from luminous objects such as the Sun, light bulbs, and flames. Key properties:
White light is not a single colour — it is a mixture of all the colours of the spectrum. When white light passes through a triangular prism, it is dispersed (split) into its component colours, from lowest frequency (longest wavelength) to highest:
Violet · Indigo · Blue · Green · Yellow · Orange · Red (mnemonic: VIBGYOR)
A rainbow forms when sunlight is refracted and dispersed by water droplets in the atmosphere — the same principle as a prism.
Light cannot pass through. It is absorbed or reflected. Opaque objects cast shadows. Examples: metal, brick, wood, cardboard.
Most light passes through. Some is absorbed and some reflected, but most transmits. Examples: glass, clear plastic, clean water.
When white light hits a coloured surface, some frequencies (colours) are absorbed and others are reflected. The colours that reach your eye determine what colour you see:
Light bounces off surfaces. The law of reflection states: the angle of incidence = the angle of reflection (both measured from the normal — an imaginary line perpendicular to the surface).
When light travels from one medium (e.g. air) into another (e.g. glass or water), it changes speed. If it enters at an angle, it also changes direction. This is called refraction:
You can see refraction by placing a pencil in a glass of water — the pencil appears bent at the water surface.
Write your answers in the spaces below. Use full sentences.
| Trial | Angle of incidence | Angle of reflection |
|---|---|---|
| 1 | 20° | 20° |
| 2 | 35° | 35° |
| 3 | 50° | 48° |
| 4 | 65° | 65° |