A botijo or búcaro is a traditional Spanish

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 porous clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 container designed to contain water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

. The botijo has the property that once filled and placed in the sun, it cools the water that it contains.

The botijo has a wide belly and one or more mouths where it is filled and one or more outputs called pitón o pitorro to drink from. The botijo is a typical element of Spanish culture and may vary in shape, color and material.

Operation

The operating principle of the botijo is as follows: the stored water is filtered through the pores of the clay and in contact with the outside dry environment (characteristic of Mediterranean climate), it evaporates

Evaporation

Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

, producing a cooling (2.219 kilojoule

Joule

The joule ; symbol J) is a derived unit of energy or work in the International System of Units. It is equal to the energy expended in applying a force of one newton through a distance of one metre , or in passing an electric current of one ampere through a resistance of one ohm for one second...

s per gram of evaporated water). The key for cooling it, is by the evaporation of bleed water, as the water evaporates, it extracts thermal energy

Thermal energy

Thermal energy is the part of the total internal energy of a thermodynamic system or sample of matter that results in the system's temperature....

 from the water stored inside the jug (and from the environment itself too).

External links

• Museo del botijo in Villena
  Villena
  Villena is a city in Spain, in the Valencian Community. It is located at the northwest part of Alicante, and borders to the west with Castilla-La Mancha and Murcia, to the north with the province of Valencia and to the east and south with the province of Alicante. It is the capital of the comarca...
  
  , Alicante
  Alicante
  Alicante or Alacant is a city in Spain, the capital of the province of Alicante and of the comarca of Alacantí, in the south of the Valencian Community. It is also a historic Mediterranean port. The population of the city of Alicante proper was 334,418, estimated , ranking as the second-largest...
  
  .
• El efecto Botijo (in spanish)
• Termodinámica del botijo (in spanish)