Physics Photo of the Week - August 25, 2023
Cumulus Clouds - Photos by Donald Collins C umulus clouds are the most familiar and most common cloud formations. Their formation is very simple: these clouds form on sunny days and result from air that has been heated by the Sun; the heated air rises to higher elevations because the heated air has expanded and has a lower density, so it rises like air bubbles in water. In rising to higher elevations the surrounding atmospheric pressure is reduced and the air expands. Air bubbles or carbon dioxide bubbles rising in a carbonated beverage do a similar expansion. A "bubble" of expanding warm air - up to several hundred meters in diameter - is "insulated" from the temperature of the surrounding air because of its sheer size. This is in contrast to the tiny bubbles rising in a beverage glass that have intimate thermal contact with the surrounding water-based beverage. When a parcel of air that is insulated from it's environment expands, its temperature lowers
