I thought I would present this before I posted it on the mandatory participation class ‘Discussion Board’. Any suggestion would be appreciated. I'm sure you all have heard it before. The question is- “Does wind affect the Pitch of the factory whistle you hear on a windy day?" The assignment illustration shows a person down wind cupping his ear toward the sound of the whistle . My answer- No it does not (although there might be a delay in hearing the sound by the one who is up wind of the whistle). My reasoning- Pitch is a measure of the number of vibrations (waves) that is experienced in a particular period of time (seconds), through a particular medium (air) at a particular point. This normally is represented in Hz (vibrations or wave lengths ‘lambda’ per second). The Doppler effect (which is really what the question is a test of) is where differently orbital positioned receivers, experience different pitches (Hz), after the sender has transmitted a wave with a constant wave length and speed (Hz), while either the receivers or the sender or both are in motion. If both the sender, and the receiver are stationary, all receivers will experience the same Pitch of vibrations that the sender is producing. This would be true whether the medium (air) is in motion or not. Further Critical Thinking- If (by chance) the receiver was upwind and the air was blowing at or faster than the speed of sound, would a receiver upwind of a sender ever hear the sound? How far off base, with any of this, am I?