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 certain elements, young children make sense of words and patterns within words. Word sorts combine both constructivist learning and teacher-directed instruction. Students receive a stack of cards containing either pictures or words that have several types of contrasting sounds, patterns, or meanings. Each student must then figure out the patterns that exist within the stack, and sort the cards accordingly. By doing this, students construct their own knowledge of words, creating a lasting understanding of how language works. This process contrasts greatly to the simple memorization related to traditional spelling tests. The more students understand about the structure of words