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 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