refraction
rih-FRAK-shun
/rɪˈfræk.ʃən/
The bending of a light or sound wave as it passes at an angle from one medium into another of different density.
Refers specifically to the shift in wave direction caused by a change in wave speed when crossing a boundary.
The story behind the word. Coined in the 17th century from Late Latin 'refractionem', meaning 'a breaking back'. Scholars observed that a straight stick dipped into water appears broken at the waterline because light changes speed and bends.
Word relationships
- bending: Bending is a broad informal term, whereas refraction is a precise scientific term involving density changes.
- deflection: Deflection implies pushing something off course, whereas refraction is a boundary transition phenomenon.
- reflection: Reflection involves bouncing back from a surface rather than passing through and bending.
Commonly confused with
- diffraction: Refraction occurs when light enters a new medium; diffraction occurs when light bends around an obstacle or slit.
Word family
- refract (verb): To cause a wave to bend upon entering a medium at an angle.
- refractive (adjective): Having the property or ability to refract light.
- refractor (noun): A lens or optical instrument that utilizes refraction.
Collocations
- atmospheric refraction
- index of refraction
- angle of refraction
- double refraction
Example sentences
- "Atmospheric refraction causes stars near the horizon to appear slightly higher in the sky than they actually are." Atmospheric science
- "Newton demonstrated that the refraction of light through glass separates white sunlight into visible spectral colors." Prism demonstration
Memory hook
Light FRACTIONATES or breaks its straight path during REFRACTION. Light breaking direction across a boundary.
When not to use
Do not confuse with reflection, which is light bouncing back off a surface without entering the material.
Fun facts
- Deserts mirages are illusory puddles caused by atmospheric refraction bending light through hot surface air.
Related words
Explore more words
attenuation, deflection, wavelength, deflect, frequency, reverberate
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