Howdy! can be replied to with just a nod and a smile. It simply means Hi! in Texan - not How are you doing?. Or you might reply, Hey Y'all Doon? if you want to engage in proper Texan interactions. Replying in proper English, well pronounced, with each syllable clearly spoken, is HIGHLY discouraged.
The crest of a wave is the point of maximum positive displacement, or upward movement, away from equilibrium, or an undisturbed state. The opposite of crest is trough, which is the point of the greatest negative, downward displacement.
The following illustration shows a cross-section through a transverse wave *. Switches below the main window can be used to label the following features: Crest - the highest point in the wave. Trough - the lowest point in the wave. Wavelength * - the horizontal distance between successive crests, troughs or other parts of a wave. Wave height - the vertical distance between the crest of a wave and its neighboring trough. This term is commonly used when describing water waves where the undisturbed surface is not easily determined.