Among 19 playgrounds renovated over the past decade, sand has disappeared from 16 of them. Many parents believe that sand is an essential component of an imaginative (albeit messy) childhood. Susan Osterhoff, director of the sensory-play program Project Commission, says sand helps kids develop an understanding of maths and science.
However, parks departments across the USA have been moving away from this type of creative play for years for a variety of reasons: They are inaccessible for people with disabilities, they clog nearby plumbing and they eat away at rubberised playground flooring. Plus, they cover lurking dangerous debris, such as glass and animal faeces.