A bright sunny day is always a pleasure in the cold winters. On a similar day, Sahil was very excited while going to school. On his way to school, his friends also joined him. Sahil, you look quite excited today. Yes, Sabina, today it's going to be a lot of fun in school. What's so special about today? Sahil, are you excited about today's activity? Yes, exactly. Don't you remember? Rohit Bia had said that he is going to take today's class in the garden. As soon as the first bell of the day rang, Rohit Bhaya came into the classroom and he asked all the children to walk towards the garden in a queue. Rohit Bia, what are we going to do today? You have asked question at the right time, Sahil. First of all, let's all sit in a circle. We are here to make different types of art paintings and crafts for the upcoming art exhibition. This time, the theme is nature. For the exhibition, can we pick some items from the garden as well? Yes, Rohit Bhaya, there are many dried leaves here and pebbles too. We can make something beautiful out of it. So let's first collect these things. They all started collecting dried leaves and small pebbles from there. Rohit Bhaya brought a big tub and kept it in the garden. All the children started putting the chosen items in the tub. Rohit Bhaya, dried leaves, pebbles and soil have been mixed in this tub. Yes, now we may have trouble making art's object from. We should separate all these substances. I liked Aman's suggestion. We can separate all these substances. What is separation? Sahil, when we separate a substance from any mixture, it is known as separation of substances. Rohit thought this is a great opportunity to discuss with everyone about the separation of substances. Children, can anyone tell me how we will separate this mixture? It will be done easily. We can pick up leaves and keep them in one place and pebbles at the other place. Only the soil will be left in the tub. Sabina is absolutely right. Can we find some other examples around us where we can separate substances in a similar way? Yes, when my mother brings vegetables from the market in a bag, all the vegetables are mixed together. I take them out of the bag and keep them in separate baskets. When my father cooks rice, he first cleans the rice grains. Then he removes small pebbles by hand and then separate other impurities by washing them with water. Wow, you all gave very good examples. All these are examples of separation of substances. There are various processes of separation of substances. The easiest of which is the process of hand picking. It means separating substances using hands. But can you imagine that if the material was not vegetables or grains of rice instead, some other small sized substances, then how would we separate them? Yes, I know. When dad makes tea, he filters the tea leaves out of it and separates it. So what do you think? Is this also a method of separating substances? Yes Rohit Bhaiya, in this method two types of substances are being separated. The only difference is that one of the substance is liquid and the other one is solid. Sabina is right. In this way, when the substances are separated from a mixture using a sieve, the process is called sieving. Can anyone tell me where else this type of process is seen? Yes, we separate the impurities from the floor by sieving before making the chapati. I have also seen a large sieve at the construction site. It helps separate the pebbles from the sand. Very good. Separation of substances is done by many such processes. What are the other processes? Threshing and sedimentation are also used to separate substances. Rohit Bhaiya pulled out some pebbles from the top in his fist. Along with the pebbles, some sand also came into his hand. He opened his fist, he blew on his hand and all the sand flew away. And the pebbles remained in his hand. Oh wow, this also happens even when wheat grains are clean in the house. All the lighter particles fly away. And this process is called winnowing. When two components are separated with the help of wind, that process is called winnowing. Can anyone explain what happens in this process? Rohit Bhaiya with the help of air, light substances are removed and heavy substances remain there. Aman is right. This process is mostly used to remove impurities from the crops. And what is the process of threshing? You must have seen the wheat or rice fields. The grains of wheat or rice which are planted are dried in the sun and tied in a bundle and then beaten up. During this time, the grains are separated from the plant. This process is sometimes done with the help of bulls or machines. This process is called threshing. Oh wow, all of this is very interesting. What a fun class this was. We collected things for the art exhibition and we also came to know about the processes of separation of materials. Such as handpicking, threshing, winnowing and sewing.