Why do prisms create rainbows?
Show answer & explanation
Answer: Wavelengths bend at angles
Wavelengths bend at angles ✓ — Correct! White light contains all visible wavelengths (colors). When entering a prism, different wavelengths refract at slightly different angles—violet bends most (shorter wavelength, higher refraction), red bends least. This separates white light into its spectrum. Called dispersion! Newton demonstrated this with prisms in 1666.
Prism reflects internal colors — Wrong. Prisms don't contain internal colors. They separate existing wavelengths in white light through differential refraction (dispersion).
Light speed changes produce colors — Wrong. Speed does change in glass, but colors appear because different wavelengths refract at different angles, separating the spectrum.
More Light & Vision questions
- Indigo jeans look blue. Which light is the dye mostly taking away?
- Why are blue-green or white night lights often worse for insects than redder light?
- Moths circling a lamp are not simply aiming at it. What flight reflex gets hijacked?
- Why does glass break light into colors?
- Why do we see darkness when eyes are closed?
- Why do sunsets appear red and orange?
