Plasticity of soil can be determined by using

Plasticity of the soil is the ability of a material to undergo permanent deformation under stress without cracking. Fine-grained soils become plastic as their moisture content is increased, leading to a loss in shear strength and stability.
The plasticity of soil can be determined by using Atterberg’s Apparatus. it helps in determining with a series of laboratory tests that classify the properties of silt and clay soils at different moisture contents.