The pH of water at ${25}^{o}C$ is $7$. When it is heated to ${100}^{o}C$, the pH of water:

A wave in which the particles of the material move up and down as the wave goes from left to right is known as:

What should be done to increase the pitch of a string instrument?

I. Increase the length of the string used.

II. Decrease the gauge of the string used.

III. Loosen the string.

IV. Tighten the string.