differential
dif-uh-REN-shul
/ˌdɪfəˈrɛnʃəl/
A gear assembly that allows the outer drive wheel to rotate faster than the inner drive wheel during a turn.
In engineering, it specifically refers to the ability to handle 'different' speeds simultaneously.
The story behind the word. Derived from the Latin 'differre' (to carry apart). In mechanics, it was applied to the gear system that allows wheels to 'carry' their speeds 'apart' or differently from one another.
Word relationships
- diff: Common mechanic's slang for the differential.
Commonly confused with
- difference: Difference is the quality of being unlike; a differential is a specific mechanical device.
Word family
- differentiate (verb): To recognize or create a difference.
Collocations
- limited-slip differential
- locking differential
- rear differential
Example sentences
- "Without a differential, tires would scrub and skip during turns because the inner and outer wheels must travel different distances." Explaining the physics of turning.
- "A locking differential is used to ensure both wheels spin at the same speed, which is helpful in mud or snow." Off-road capability.
Memory hook
The 'differential' handles the 'difference' in wheel speed. Differential = Different speeds.
When not to use
Don't use it in a general sense of 'a difference' unless you are in a mathematical or mechanical context.
Fun facts
- The concept of the differential was known in ancient China, used in the 'South-Pointing Chariot' to keep a statue pointing south regardless of turns.
- Most modern cars have an 'open' differential, which is cheap but can leave you stuck if one wheel is on ice.
Related words
Explore more words
transmission, mechanism, accelerate, traction, differentiate, synchronization
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