Softness in materials is defined as what characteristic?

Softness in materials is primarily characterized by its absence of hardness. Hardness refers to a material's ability to withstand localized plastic deformation, such as indentation or scratching. When a material is described as soft, it means that it has a low hardness value, allowing for easy deformation under force. This characteristic is important in various applications, as softer materials can be easier to cut, shape, and manipulate compared to harder ones.

While concepts like flexibility, resistance to deformation, and density have merits in material science, they do not define softness as specifically as the absence of hardness does. For instance, a material may be flexible yet still hard, or have a high resistance to deformation but still be considered soft. The essence of softness lies in the material's low hardness, which influences how it behaves under stress and strain.