The rules for positioning of syllable stress in Latin are relatively simple; they are as follows:
In two-syllable words, the stress always falls on the first syllable.
In three or more syllable words, the stress falls like so:
a. If the penultimate (second-to-last) syllable is heavy, the stress is placed on it.
b. If the penultimate syllable is light, the stress is placed on the antepenultimate (third-to-last) syllable.
This alone is all well and good, there are only three-ish rules to memorize, and the irregular couple-syllable words that are exceptions to this rule are easy to learn and recognize. However, what always trips me up is the use of the terms "heavy" and "light" (or other related terms) to describe which syllables are stressed.
For the duration of my Latin learning experience, I have simply assumed that syllables containing long vowels were heavy and that syllables containing short vowels were light, or simply just making a qualitative judgment to determine whether the penultimate or antepenultimate syllables "felt" heavy or light. Neither of these methods has ever felt sound to me and I am almost 100% certain that I am not distinguishing heavy and light syllables correctly. Thus, my question:
What are the differences between heavy and light syllables and how does one go about identifying them?