Here's why:
* Short vowels typically have a quick, sharp sound. In "bow," the "o" sound is short and quick, similar to the sound in words like "hot" or "cot".
* Long vowels usually have a drawn-out, longer sound. In "bow," the "o" sound is not drawn out.
It's important to note that there are some variations depending on the word's context and pronunciation, but in the general case, "bow" has a short vowel sound.