Page 112 - Science Class 6 Times Publication

Winnowing

Winnowing is a process of
removing lighter things from
the heavier things. This process
is used to separate  ne rice
grains from the husk or coarse
rice grains from husk while
harvesting.

If systematic jerks are provided
to the winnowing tray, the
mixture of rice grains and husk moves up. In this process, the lighter
husk is blown away by the air but rice grains remain in the winnowing
tray. We can separate rice grains from husk in large scale during
harvesting. In this process, the energy of the wind is also used.

Sieving

A sieve is a vessel which has tiny holes at

its bottom. Generally, a ne net is used on
the bottom of a sieve. The process of using a

sieve to separate the components of a mixture
is known as sieving. If the components of a
mixture differ in the size of the particles,
the sieving method is used to separate them.

Sieving is usually done to separate ne wheat

our from unground wheat grains and other
unwanted particles.

Sedimentation and decantation

Sedimentation and decantation are used to remove the suspended
impurities such as sand, mud, etc from the mixture. These two

processes are carried out one after another. At rst, the process of
sedimentation of the suspension is done and then decantation.

Times' Crucial Science and Environment 108 Book 6