Handpicking : A Separation Technique

All substances are not present in their pure form in nature. Most of the substances are present in the form of mixtures. We can separate useful components of the mixtures by using various methods of separation. Handpicking is one of the methods of separation. It is a very old separation technique. You must have seen your mother separating stones or other impurities from rice by handpicking and washing it before cooking. You generally use different methods of separation in your daily life. Handpicking is the most common one. 

If you want to separate black grapes from the mixture of black and green grapes, then you will simply pick black grapes using your hands from the mixture. In this way, you are using the handpicking separation method. Thus, we can define handpicking as the separation method in which components of a mixture can be separated by just picking them out of hands. 

Handpicking is a very simple method of separation. If we give you a bucket full of mangoes and apples and ask you to separate them, then which method of separation will you use? You will start picking out one kind of fruit, either mango or apple. In this way, you will separate one from another. The separation technique which you are using here is handpicking. 

Many heterogeneous mixtures in which the particles are large enough are separated by using handpicking separation method. While in some heterogeneous mixtures, you can’t separate by this method, such as sand and salt. To separate sand and salt, we dissolve the mixture in water and then filter it. In this way, salt gets dissolved in water while sand is left as a residue. 

Thus, we can say handpicking is used for separating slightly larger sized impurities such as pieces of dirt, stones, husk from wheat, rice, pulses etc. It can be used for those mixtures as well which differ in colour, shape or weight.

Examples of Handpicking Separation Method 

Following are the examples of handpicking separation method –

• For separating the mixture of chillies and lady’s finger (on the basis of size).

• For separating stones from rice, pulses and wheat (on the basis of size and colour).

• For separating rotten potatoes from fresh ones (on the basis of shape, colour and smell).

• For separating different kinds of vegetables from the mixture of vegetables in the basket (on the basis of shape, colour, size).

• For separating the mixture of yellow dal and rice (on the basis of colour).

• To separate rotten and fresh potatoes (on the basis of appearance, colour and odour).

• To separate yellow lentils and the rice (on the basis of the colour). 

Advantages of Handpicking Separation Method

Following are the advantages of handpicking separation method –

• It is a very simple and easy method of separation. 

• It doesn’t require any kind of equipment to proceed. 

• It takes very little time when performed for a small quantity of mixture. 

• It doesn’t require any kind of preparation. 

Limitations of Handpicking Separation Method 

Following are limitations of handpicking separation method –

• We can’t separate all heterogeneous mixtures by handpicking. 

• It is a very time taking process if the quantity of the mixture is large. 

Points to Remember

• The handpicking separation method is taken into consideration for a very small amount of the material.

• No chemicals are possible to be separated by the method of handpicking.

• The margin of error is large and it is a very tiring and time-consuming process. 

• No types of machinery are involved in this process of separation. 

• Handpicking does not need any prior preparation or any future steps to be involved for the separation.

Apart from handpicking, many other methods are used to separate mixtures such as threshing, winnowing, sieving, sedimentation, decantation, filtration, evaporation, condensation, sublimation, distillation, magnetic separation etc.