Canvas water bags work through a process of evaporative cooling, keeping water significantly cooler than the surrounding air.
Here's a breakdown of the mechanism:
- Bag Saturation: The canvas bag is first thoroughly soaked with water.
- Filling: The bag is then filled with drinking water.
- Placement: Historically, these bags were hung on the front of vehicles (hood ornament or bumper) during travel, particularly in hot climates.
- Seepage and Evaporation: Water slowly seeps through the canvas material to the outside surface.
- Cooling Effect: As the water evaporates from the canvas surface, it absorbs heat from the remaining water inside the bag. This evaporation process lowers the temperature of the water within the bag. Typically, the water temperature could be reduced by around 12 degrees Fahrenheit (approximately 6.7 degrees Celsius) compared to the ambient air temperature.
In essence, the canvas water bag acts as a passive cooling system relying on the natural process of evaporation to maintain a cooler water temperature.
