Strings (tennis)
The material used in tennis string can significantly affect a player's performance, and even health. Several materials are used to make tennis strings. They vary in terms of elasticity, durability, rebound efficiency, tension holding capability, and manufacturing cost, among other considerations.
Violin
While most violins have four strings, there are violins with additional strings. Some have as many as seven strings. Seven strings is generally thought to be the maximum number of strings that can be put on a bowed string instrument, because with more than seven strings, it would be impossible to play a particular inner string individually with the bow. Instruments with seven strings are very rare. The extra strings on such violins typically are lower in pitch than the G-string; these strings are usually tuned to C, F, and B. If the instrument's playing length, or string length from nut to bridge, is equal to that of an ordinary full-scale violin; i.e., a bit less than , then it may be properly termed a violin. Some such instruments are somewhat longer and should be regarded as violas. Violins with five strings or more are typically used in jazz or folk music. Some custom-made instruments have extra strings which are not bowed, but which sound sympathetically, due to the vibrations of the bowed strings.