Question

Problem 7

Answer 1

Given information

In short, the pitch rises to first order according to the temperature.

 

The wavelength of the played note will not vary with temperature if the pipe length remains constant. However, because the pitch (frequency) of a played note is equal to the speed of sound divided by the wavelength, the pitch will change accordingly as the speed of sound varies. So, the question is, how does sound speed change? In other words, the speed of sound rises to first-order proportionate to the temperature.

Step-by-step explanation

Step 1.

If the air pressure remains constant as the temperature changes, as I presume it will, the air density will drop as the temperature rises. (The ideal gas law states that the molecules move about more.) At constant pressure, the square root of air density is inversely proportional to the speed of sound, hence the speed of sound increases as the air density falls (due to the increasing temperature).