Winnowing - Definition, Advantages and Disadvantages, Threshing FAQs

What is Winnowing?

In daily life, we go through any type of process of separation of one particle from another. Like in common daily things we separate stones from rice and pulses, cream from milk, tea particles from tea. There are a number of separation processes for such types of separation. This separation process is generally divided on the basis of the state of matter particles like the given mixture is of solid-solid, liquid-liquid, solid-liquid, solid-gas, etc. The particles of one or more substances mixed with each other are known as a mixture. The mixture is also of two types:

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This Story also Contains

1. What is Winnowing?
2. Define winnowing
3. Winnowing in Agriculture
4. Principle of Winnowing
5. Winnowing Machine
6. Advantages of Winnowing
7. Disadvantages of winnowing
8. Winnowing and Threshing

1. Homogeneous mixture in which the composition of the mixture remains constant throughout the process.

Example: Lemon water; when we dissolve lemon in water then the taste of the whole solution remains as such throughout the solution.

2. Heterogeneous mixture in which composition is not the same or we can say that particles are not distributed uniformly. We can easily detect the mixture by seeing whether it is homogeneous or heterogeneous as it contains a non-uniform composition.

Example: Pizza; like in pizza, all the vegetables are non-uniform in nature.

Hence for the separation of mixtures, many methods like hand-picking, sieving, threshing, winnowing, etc are mentioned for solid-solid mixtures while distillation, filtration, etc are used for solid-liquid substances. From this, we can get an idea that winnowing is one of the methods used for separation.

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Below is the list of the NCERT solutions for Class 11 and Class 12 Chemistry solutions. Along with this candidates can find the link where Solutions of all other subjects is also provided. NCERT solution is a good source to cover the topics in detail for the Board exams.

• NCERT Solutions for Class 11 Chemistry
• NCERT Solutions for Class 12 Chemistry
• NCERT Solutions for All Subjects

Define winnowing

Winnowing is defined as the method through which lighter particles get separated through heavier particles with the help of wind. This type of process is used for that mixture in which both the particles are of solid nature but one particle is very light as compared to another particle so it can easily get separated with the help of wind. The word winnow is generally derived from the English word ‘windwian’ which represents the separation of mixture with the help of air. An example of winnowing is the separation of grains from husk. The method of separating grains from chaff is called threshing.

Separating the grain from the chaff is basically known by the process called threshing. Threshing can be defined as a process of separating grain from chaff, during this process mixture which contains wheat and husk particles is brought down from some height with this drop-down the lighter husk particles will blow away with the air which collected in the shape of the heap at some distance. Husk also takes the shape of a heap at some other distance. Dirt particles can be easily removed from grains with the help of winnowing process and corns are also separated from straw with the help of this process.

Winnowing in Agriculture

With the help of this picture, we can conclude how winnowing is useful to farmers as by this process we can easily separate out the husk particles from grain. Being lighter in weight it will blow out with air as shown in the image.

Principle of Winnowing

Winnowing is generally based on the principle that the mixture which contains two components out of these two one is lighter in comparison to the other so that only lighter particles will blow with air. This mixture is put down from some height then lighter one will separate from the heavier one with the blow of wind.

Winnowing Machine

Winnowing doesn't need any type of heavy machines. But some machines are designed for the process called winnowing. The first machine which was designed for winnowing purposes is known by the name wind winnowing machines. It was designed by the scientist named Andrew Rodger in the year of 1737. He is basically from Scotland and his profession was farming, he developed this machine for separating corn and to this machine, he gave the name fanner. After his discovery, so many other types of machines for winnowing will come in the market but in this era single machines work two processes called winnowing and threshing which make their work easy and also time economical as they can complete two tasks in the same time which saves their both time and energy.

Advantages of Winnowing

This is also said to be the main advantage of winnowing that it does not need any type of machine; it basically depends upon the tendency of human beings. It is very cheap to perform and it is not much time consuming. We know that how to separate stones from rice the method will be hand picking if there are stones in the rice or grains we can easily separate them out with hand picking method but this method is not applicable for removing husk particles from grain as these are very light in weight so it is not possible to pick them all by hand picking method, therefore we apply winnowing method here.

Disadvantages of winnowing

Like advantages there is also a number of disadvantages of winnowing which can be explained as:

1. Winnowing process is suitable only for those mixtures out of which one is lighter as compared to the other so it is not applicable for those mixtures which have the same size or we can say it is not applicable for heavy particles mixture.

2. Winnowing is the process in which lighter particles will blow out with the help of air so it is not possible to blow heavier particles this will give a limited scope to this process. Also when the day is non-windy then winnowing is also difficult.

NCERT Chemistry Notes:

Below are the Notes for Chemistry Class 11th and Class 12th. Students can also find the link to Notes of other subjects. Candidates can have a look at these notes for revision purpose.

• NCERT Notes Class 11th Chemistry
• NCERT Notes Class 12th Chemistry
• NCERT Notes For All Subjects

Winnowing and Threshing

The winnowing process is done after threshing. We have to consider the main differences between these two processes called winnowing and threshing.

1. Winnowing is the process of separating husk from grains while threshing is the process of grain from the chaff.

2. Winnowing process is used by farmers in such a way that grains and husks are allowed to fall from height and husk will blow out with the help of air during this process and in the threshing crop is striking on some hard sphere.

3. Winnowing is done after threshing while threshing is done before winnowing. These two processes are interrelated to each other.

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NCERT exemplar questions provides good questions for the practice. All the concepts can be covered in more detail with the help of NCERT exemplar solutions.

• NCERT Exemplar Class 11th Chemistry Solutions
• NCERT Exemplar Class 12th Chemistry Solutions
• NCERT Exemplar Solutions for All Subjects