Water in the sand between the two pots evaporates through the surface of the larger pot, where drier outside air is moving.

VOA: special.2009.02.09

Hundreds of the islands are only pieces of sand that extend a few feet out of the water.

VOA: special.2010.03.22

Engineers have found that wetlands, grassy fields and soil or sand filters can take in stormwater with different levels of pollution and release water with a relatively constant cleanliness.

VOA: standard.2010.08.04