Final answer:
Rain drops that freeze through a layer of cold air become sleet, which is different from snow or hail and forms under specific atmospheric conditions.
Step-by-step explanation:
When rain drops pass through a layer of cold air and freeze, the result is a form of precipitation known as sleet. Sleet is essentially rain that freezes into ice pellets before reaching the ground. This is different from snow, which is formed directly from water vapor in the clouds turning into ice crystals without first becoming rain. Unlike hail, which can form in thunderstorms as large ice balls from upward drafts of air, sleet forms during a specific atmospheric condition where a warmer layer sits above a freezing layer closer to the ground.