Sand art and play
A sand castle is a type of sand sculpture which resembles a minature building. The two basic building ingredients, sand and water, are available in abundance on a beach and so most sand play occurs there, or in a sandbox.
A variant on the sand castle is the drip castle, made by mixing extra water in with the sand, and dripping this wet sand from a fist held above. When the sand/water slurry lands on existing sand structures, the water is rapidly wicked away leaving the blob of sand in place. The effect is Gaudi-esque.
Sand castles are typically made by children, simply for the fun of making them. However, adults sometimes engage in contests making sand sculptures, in which the goal is to create structures which don't appear to be constructed just from sand; they can become large and complex. Other vulnerable media are ice and snow, leading to ice sculptures and snow sculptures.
An example of extremely sophisticated sand art is the Buddhist mandala.
The sand must be fine, or the grains will not stick together. Dry sand is often loose, wet sand is more solid, except when it is very wet. Sand may dry or get wetter, changing the solidity of structures. "Landslides" are common.
The main tools for construction are a shovel (although using the hands only is also common) and a bucket or other container to bring water from the sea to the "construction site". Also pieces of wood etc. can be used to reinforce structures.
One of the main attractions of a sandy beach, especially for children, is playing with the sand, with more possibilities than a sandbox. One can make a mountain, a pit (encountering clay and the water table), canals, tunnels, bridges, a sculpture (representing a person, animal, etc. like a statue, or a scale model of a building), etc. If the beach is at an ocean, or at a sea connected to an ocean then there are tides; the height depends on coastal topography such how wide the connection with the ocean is. These tides add attractive dynamics: at flood-tide the water enters previously dry ditches and pits, and one can try to keep areas dry by dikes, etc.; at ebb-tide one can try to keep water in a canal by deepening it and lenghtening it, keeping it connected to the retracting sea.
If one returns the next day much erosion is apparent, in fact only larger structures can be found again.Construction
Alternatives to sand castles
