Derailleur gears battery pack and to a small electric motor that drives the derailleur. Although expensive, an electronic system could save a racing cyclist time when changing gears. Derailleur gears Derailleur gears are a variable-ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets of different sizes, and a mechanism to move the chain from one sprocket to another. Although referred to as "gears" in the bike world, these bicycle "gears" are technically "sprockets" since they drive or are driven by a chain, and are not driven by one another. Modern front and rear derailleurs typically consist of a
Word sort - their spelling or orthography - the more efficient and fluent their reading will be. Word sorts place instructional emphasis on the exploration of patterns that can be detected in the sound, structure, and meaning features of words. Thus, word sorts contribute to orthographic or spelling knowledge, the engine that drives efficient reading as well as efficient writing. There are three different types of word sorts: sound sorts, picture sorts, and word sorts. Sound sorts can take on many forms in a primary classroom and this is essential because sound is the first layer of English orthography. Sound study can