Difference between of seiving and winnowing​

Winnowing is the separation of solid-solid separated by size and weight whereas sieving is the separation solid-liquid judged by shape and size. Winnowing is used to separate heavier and lighter components of a mixture by wind or blowing air. ... Sieving is used when components of a mixture have different sizes.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).