Derailleur gears operates the lever while pedalling, the change in cable tension moves the chain-guide from side to side, "derailing" the chain onto different sprockets. For more information about the choice of particular gear ratios and sprocket sizes, see Bicycle gearing. "Derailleur" is a French word, spelled "dérailleur" in French, derived from the derailment of a train from its tracks. Its first recorded use was 1930. At least one notable bicycle industry author has attempted to promote the anglicized spelling of "derailer". As of 2013, however, neither Merriam-Webster nor the Oxford English Dictionary has an entry for "derailer". Various derailleur systems were
Word sort words. Spelling or word study notebooks may be used to record, collect, and organize information about words and spelling patterns learned from the word sort. To complement the many 'hands on' activities students use for sorting words, digitized word sorts provide an efficient way for teachers to deliver spelling pattern differentiation. A variety of these are ready-made, including wordsortwizard.com. Research has shown that students who experience significant difficulty with spelling follow the same developmental course as other students, but do so at a slower pace. In such cases, it is critical to provide word sort words at the appropriate developmental