An evaporative cooler, also known as a zeer pot, is an ancient device that provides refrigeration for food and drinks when the temperature outside is blazing. And they're really simple to make, with just two containers that fit inside each other. Who needs an esky?
The video above demonstrates one variation of this basic cooler. As the wet sand evaporates, it removes the heat from the inner container, lowering the temperature.
As MixCat.com's video shows, the temperature starts to drop pretty quickly, but it may take some time for the zeer pot to get really cold. In six hours, the interior went from 30 degrees C to 11 degrees, while the temperature outside was 35 degrees.
This DIY project is great to have in case your electricity goes out or for keeping your beer cool in the sweltering heat (the hotter it is, the faster the evaporation and quicker the cooling).