Derailleur gears a detent or ratchet mechanism which stops the gear lever, and hence the cable and the derailleur, after moving a specific distance with each press or pull. Indexed shifters require re-calibration when cables stretch and parts get damaged or swapped. On racing bicycles, 10-gear rear cassettes appeared in 2000, and 11-gear cassettes appeared in 2009. Most current mountain bicycles have either. Many modern, high-end mountain bikes have begun using entirely one chain ring drivetrains, with the industry constantly pushing the number of rear cogs up and up, as shown by SRAM's Eagle groupsets (1 by 12) and Rotor's recent 1
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