Freezing ice in the freezer makes it last longer than leaving it on the countertop due to the principles of heat transfer and the difference in temperature between the freezer and the countertop environment. Here's how it works:
Temperature Difference: The freezer is designed to maintain a much lower temperature than the room temperature of your countertop. Typically, freezers are set to around 0 degrees Fahrenheit (-18 degrees Celsius) or lower. On the other hand, room temperature can vary but is usually around 68-77 degrees Fahrenheit (20-25 degrees Celsius). The significant temperature difference allows the freezer to extract heat from the ice rapidly, causing it to freeze quickly.
Heat Transfer: Heat transfer occurs from a region of higher temperature to a region of lower temperature. When you place ice in the freezer, the surrounding air and walls of the freezer are much colder than the ice. As a result, heat from the ice (which is at a higher temperature than the freezer's environment) moves outwards and is transferred to the colder surroundings.
Slowing Down Ice Melting: The low temperature of the freezer helps to slow down the melting process significantly. Ice melts when its temperature rises above freezing point, which is 32 degrees Fahrenheit (0 degrees Celsius). In a warm room, the ice will absorb heat from the environment, causing it to melt faster. But in the freezer, the temperature is maintained well below freezing point, so the ice remains solid for a much more extended period.
Insulation and Enclosed Environment: The freezer provides an enclosed and insulated environment. It has thick walls and a well-sealed door, which prevents warm air from entering and cold air from escaping. This insulation helps maintain the low temperature and prevents rapid heat exchange, allowing the ice to stay frozen for longer.
Overall, the freezer's colder temperature, effective heat transfer, and insulated environment collectively work to preserve the ice and keep it frozen for an extended period compared to leaving it on the countertop where it's exposed to warmer temperatures and faster heat transfer, leading to faster melting.