The most authentic playgrounds are those which consist mainly of natural components: natural landforms, natural surfaces, even natural safety materials. Budgets, space and safety must of course be taken into account. Yet, with enough imagination, it’s relatively cheap and easy to create appealing natural play areas.
Many schools already use the five materials I’m going to discuss, but they generally deploy them on a small scale. Sand and soil, for example, are often kept in trays and brought out for occasional activities. I feel that the real benefits of these materials come when they are used on a large scale - and outdoors.