This instructable teaches how to build, more like assemble, an Evaporation Refrigerator. It is also called a pot-in-pot refrigerator or a zeer pot. This strange device has been used since 2500B.C. by many primitive and third world cultures. It works by adding water, the water absorbs the heat and evaporates, taking the heat with it. You can keep this compartment well under ambient temperature with very little effort.
You will need:
1 large clay pot without base
1 smaller clay pot with base that can fit inside the large pot with a little room
tin foil or chrome paint
a good bit of sand or dirt
Step 1: Bucket-O-Sand
Take the larger pot and start filling it with dirt. It may be desirable to plug the hole. Occasionally stop and set the smaller pot inside the larger pot. Fill the larger pot untill the smaller pot's rim sit level with the rim of the larger pot. Set the pot of sand to the side.
Step 2: Shine 'er Up!
This step is optional. It will work without the shine. Take the smaller pot and base and paint the inside of the pot and the bottom of the base chrome or wrap tightly with foil. Allow them to dry.
Step 3: Finishing the Zeer Pot.
Take the smaller pot, plug the hole and place it in the larger pot. Fill the gap between the walls with sand unrill the sand sits a bit below the lip of the pot. The base of the smaller pot should fit nicely over the smaller pot.
Step 4: Using Your New Zeer Pot
Place your cold items in the smaller pot. Pour water on the sand untill its just over the sand. The heat from the sun and moonlight sdoes the rest. Supposedly direct/indirect sun light is better than all day shade. Supposedly using a wet rag can replace the base as a lid.