The technique used to separate pebbled and sand is called sieving. Sieving involves using a sieve, a mesh or perforated container, to separate particles of different sizes. In the case of pebbles and sand, the sieve would have holes large enough to allow the sand particles to pass through, while retaining the larger pebbles on top. By shaking or vibrating the sieve, the sand particles gradually fall through the holes, leaving behind the pebbles on the sieve. The process can be repeated with sieves of different pore sizes to obtain different fractions of particles based on their size. Sieving is a simple yet effective technique widely used in various fields such as soil analysis, construction, mining, and food processing.