Guitar strings often go “dead" – become less responsive and bright in tone – after a few weeks of intense use. A researcher whose son is a classical guitarist hypothesized that dirt and oil, rather than changes in the material properties of the string, were responsible.
Which of the following investigations is most likely to yield significant information that would help to evaluate the researcher’s hypothesis?
(A) Determining if a metal alloy is used to make the strings used by classical guitarists.
(B) Determining whether classical guitarists make their strings go dead faster than do folk guitarists.
(C) Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars.
(D) Determining whether a dead string and a new string produce different qualities of sound.
(E) Determining whether smearing various substances on new guitar strings causes them to go dead.
The first sentence of the given narration states it as an observed fact that guitar strings often become less responsive and less bright in tone after a few weeks of intense use. It also quotes one researches as stating that this deterioration is due to dirt and oil, and not due to changes in the material properties of the string.
We have been asked to identify the choice which can form an investigation that will help to evaluate the researcher’s hypothesis.
We can easily guess that any relevant investigation will have to involve the use of some foreign substances like dirt and oil on the strings. For example if, during an investigation, extreme care is taken to ensure that the strings are always kept free of any foreign substances, but it is still noticed that there is progressive deterioration in the quality of the music produced by the strings, one can say that the researcher’s hypothesis is wrong, and that the deterioration in quality is attributable to the material properties of the string alone.
On the other hand, if the deliberate smearing of some dirt and oil on brand new guitar strings does not result in the deterioration of the quality of music produced by them, then also the researcher’s hypothesis can be considered to be wrong. Conversely, if such deliberate smearing of foreign substances on brand new guitar strings results in the immediate deterioration of the quality of the sound produced by them, them, then the researcher’s hypothesis would be strengthened.
From a quick reading of the choices, we can notice that it is only (E) which mentions the smearing of foreign substances on the guitar strings, and is the answer.
None of the other choices is relevant to the hypothesis of the researcher that dirt and oil, rather than the material properties of the string, are responsible for the guitar strings going “dead".