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Hello students, this is Urmi Tiwari and you are watching your favorite educational channel Magnet Brains where we give you 100% free quality education We are going to start class 6th of Science Before starting science, it is important to introduce you to the other teachers of the subject if you have already met them, then it is a very good thing but these are the teachers from whom you learn English, Hindi, Maths and Social well, their support is also important for you only then you will be successful in your exams with this in mind, let's start chapter number 4 which is called sorting materials into groups sorting means sorting separating so, if we talk about materials what is material? Material means there are many materials around us like some are cotton materials some are metals metals have different metals some metals like you might have seen in your kitchen there is a metal of steel some metals are of copper some metals are of gold, silver, aluminium all are different metals similarly, what are other materials in our house? Furniture, bed all these are made of wood other than this there are many other things like plastic, rubber what are all these?

All these are materials and all these materials are around us so in this chapter we are going to study about these materials what materials we have what materials are there in our classroom where we are sitting in our room, what all materials are there around us and what are the properties of these materials we will discuss all these things in this chapter no. 4 ok, so let's do a quick review what all we have to study in this chapter so first of all we have to study Objects around us that all the objects around us what are those? Now as I told you just now some objects are like this which are made of wood some objects are made of cement some objects are made of plastic

object hai, wo kaun kaun se hai? Ab aapne jaise maine abhi aapko bataya kuch object aise hote hain jo ke aapke wood se

bane hote hain kuch object aapke cement se bane hue hote hain kuch object plastic ke matlab ki materials jo hai na wo bahut tare tare ke ka hota hai jo ke aapke aas paas aapko milega, right? Ab iske baad hume padhna hai, properties of material, toh property ka matlab kya hota hai? Jaise ki meri property hai, ki main dikhne mein kaise hoon, my height kya hai meri, okay? And main kya tez daur sakti hoon ya nahi, ya phir main kya, matlab singing kar sakti hoon, they are the properties of a human being okay usi tarike se material ki bhi properties hoti hain jaise ki appearance ki koi cheez kaise appearance me dikhti hain, appearance ka matlab kya hota hai ki soft hai, hard hai, hardness ki koi cheez kaise hai, soluble or Appearance means soft, hard, hardness, soluble or insoluble materials. Objects may float or sink in water, some float on water, some sink in it.

Transparency, some objects are such that if we keep transparency, then about those objects, means all these properties of different materials are there. Okay? Like if we talk about wood first, then how is wood? Which property will be seen in it, right? So, we will discuss everyone's property according to these 4-5 points in this chapter.

Okay? So, first of all, we have to read about materials in this chapter. So, I told you about materials, that all those things which are made of a particular thing that is called its material that is called its type of material like if I talk about cloth, cloth is also made of different types of material like cotton cotton is its material, silk that silk is its material if I talk about bottles bottles are also made of different materials like plastic bottle metal bottle so which material is it made of? So you will say that my bottle is made of plastic is it clear? Now examples of other materials like ornaments that females wear so from what are these ornaments made?

If someone asks you hai to aap

kya bataoge ki jo mere bottle hai wo plastic se bani hoi hai, clear hua? Ab aur material ke examples, jaise ornaments jo females pehenti hai, to ye ornaments kisse bane hoi

hai, kis material ka hai agar aapse puchega, to aap bataoge ki ye ek tarika ka metal hai jo ki gold ho sakta hai, silver ho sakta hai, hai na? To ye material matlab ki koi particular cheez, kis cheez se bani hoi hai, wo uska

material because it is a type of metal which can be gold or silver so this material means that any particular thing which is made

of that material is called material so we have seen that our food and clothes, there is much such a vast variety of object everywhere and some are of metal so these are 3 categories now in those categories also there are many more categories like if I talk about cloth so what type of cloth is cloth? Is it a pant shirt or a salwar kameez or if I characterize it as a pantshirt then what material is it? It is a matter of material. So you will say it is cotton, silk, polyester or nylon. Similarly, if I talk about wood, then which wood is made of?

It is cesium or we have taken any other normal wood, all the types of wood will come in it. That means, 1 type of material can also have many things. Now, how is this material characterized? So, it is characterized by touching them. Okay?

If there is a cloth, then why is it? Because it is very soft to touch. If it is a cloth, it can take a lot of surface. If we see the properties of wood, how are the different woods in wood? There is a sagoon or sesham.

The wood of sagoon looks very shiny. Sesham can be less shiny. Wood ki aliye ghar

apn properties dekhe, wood mein alag alag wood kaisi hoti hai, toh koi saagon hota hai, sesham hota hai, toh saagon ki wood bahut zyada

shiny dekhti hai, sesham thoda kam shiny ho sakta hai, hai na, babool ka jo wood hai woh bahut zyada rough dekhta hai, toh isme bhi variety aapko dekh jayegi alag alag type ka, kyuki unka texture alag hota hai, koi zyada hard hoti hai, is aisaab se aapko alag alag material dekh jate rough, so in this also you will see variety of different types, because their texture is

different, because it is hard, so according to this you see different materials.

So we see around us a chair, a lock cart or a cycle, cooking utensils, books, clothes, toys, water, stones and many other objects. All these objects have different shapes, colors and uses. Ab hamare aas paas bahut saare objects hain. In sabhi object ka kya hai? Color bhi different hota hai, shape bhi different hota hai aur size bhi different hota hai.

So look around and identify objects that are round in shape. Ab kuch object aise hote hain jo ki round shape ke ho, kuch object aise hote hain jo ki flat ho. To bhai round shape ke kuch object jaise rubber ball hai, football hai, glass ka marble hai ye sab kaise hote hain? Round shape ke. If we include objects that are nearly round our list could also include objects like apple, orange and earthen pitcher that is ghara okay so why are we reading all these things?

Basically we should know that there are many objects around us and what do we have to read? We have to read material and now I will explain how this story is related to material so what is around you? There are many types of objects some objects are round shaped so what all are round shaped? So they told you that there are balls, marbles all these are round shaped some are nearly round like apple, oranges or your earthen pitcher

kaun sa dikhta hai toh naone abhi aapko bataya ki balls hoti hai, marbles hote hai, ye sabhi aapke kaise hote hai? Round shape ke hote hai. Kuch nearly round

hote hai, jise apple hai, oranges hai ya phir aapka jo earthen pitcher hota hai, that means ki aapka jo ghara hum kahte hai, wo. So suppose we were looking for objects that are edible, agar kuch edible objects ki baat kare toh wo hamare aas paas bahut saare tari ki tari ki hoti hai, theek hai? Isi ki saath aapn jab aas paas dekhte hain bahut saare objects, toh humne ye dekha ki kuch objects wo aapki kisse bane hoye hoye, wood se bane hoye hai, ab wood me bhi alag alag type ke hote hai, jaise ki kuch objects humare circular hote hai, round shape ke hote hai, kuch humare square hote hai, jaise desk ho gaya, kuch aapke thodase length jinki badhi ho gaya, jaise ladder ho gaya, shade hai, pencils hai, bookshelf hai, wardrobe hai, chest of drawers, a word table so it means that your wood can be of any shape or any size now if you have used wood then there must be some quality in wood which you need in table there must be some quality in wood which you need in desk and in letter or book shelf or pencils ok? So this is your 1 object which is your material wood which makes so many objects.

In the same way what type of objects you get? So we get some objects which are made of plastic like in some examples plastic milk and juice bottles like plastic lumber or some benches or chairs are made of plastic play sets are made of plastic bottles are made of plastic plastic detergent bottles, buckets, containers, Fresh bees, stadium seats, etc. All these are made of plastic. Now, there must be a reason behind why we have made all these things out of plastic instead of wood. So, let's go.

Now, we have told you that there are many objects around us. Some objects are made of wood. Some objects are made of plastic. So, in this chapter, we will study why we have used wood here and why we used plastic here so why we used wood? Because if you can use wood in such a place that you can keep it inside the house and which is durable so you took wood like wardrobe, chest of drawers, bookshelf, pencil now wood is little light so if you make pencil with metal it will become heavy but when you will get good writing?

When you write with a light object. It should be of light weight. Desks and all these are made of wood. So that we can easily shift them from here to there in our house. Now comes the topic of plastic.

So why did we use plastic in all these things? For example, why did we use plastic in detergent? Because it is a chemical. And chemical will not react with plastic. If you put chemicals in wood, it may leak.

That's why we took plastic here. It can react with metal. But plastic will not react. That's why we took plastic here. If we talk about stadium seats, why are they made of plastic?

Because stadiums are open. If you put a wooden chair or metal in the open, what will happen when it rains? When it rains, the wood slowly deteriorates and the metal also gets rusty. Okay, so that's why there is plastic here. So, there are some qualities and properties in the objects around us, because of which we use them, like wood and plastic what other material do you get?

Like your metal you must have seen the use of metal everywhere so all your screws or repairing devices are all made of metal because if you want to repair something then if you use wood or plastic then you will not be able to repair it in a good way because if you use plastic or wood then it will break similarly, the key should be sharp so what gives you sharpness? In metal ok all the forks or cutleries you have or your pan or the 1 with which you tap water or rings why all these are made of metal? Because we have seen spoons in it for example plastic spoon like we go to market or eat street food they give you plastic spoons so what is a plastic spoon? It breaks but do you throw the spoon out of the house again and again? So to be strong we use metal spoons similarly if there is a pan in earlier times wood was used but it was not durable.

So, we use metal to make it durable, strong and hard. Similarly, there are some objects that we wear like leather. If we use leather purse, leather hat watch belt that is leather so all these are leather because it is soft and we can keep a lot of things in leather so we can make leather bags so every type of material has different properties that's why we use different materials at different places so in this whole chapter whatever things I have told you are made of different materials and what you are seeing that different materials are being used in different places why It is being used because it is a separate property of all. Like wood has a different property, it is light. So we use it in all such applications in our house.

If I want to shift things from here to there, I can do it easily. I use plastics in all such places that it is easy to carry. It is easy to carry. If you keep any chemical in it, it will not react and what will happen that during the rainy season, plastic does not get spoiled quickly but wood will get spoiled quickly and metal can rust clear so these are the benefits next, some objects are hard and shiny so they are metal so we use them in ornaments we use them in cutleries and in repairing tools we use metals and leather so all types of materials have different properties So, in this chapter I will tell you about the properties of these materials What are their properties? And along with that, we will do some activities that will help you to understand which type of material is suitable for which property ok, so this chapter is going to be very interesting in which we will study sorting of material now we are finishing the introduction here we will meet you soon in next video but before that let me tell you that we have already completed 3 chapters the complete video of those chapters the detailed video you will get it on magnetbrings.com so do watch it what you have to do select class 6 as soon as you select class 6 screen will open in which different folders are there whatever you want to read for example if you want to read science then do watch now after doing watch now you will see chapters at the bottom in those chapters there are topics, subtopics you just have to click on all of them after clicking you will see the video do watch the full video only then you will clear all the topics when you watch the video till the end you will understand all the topics so like this video, comment and tell us and share this video with your same class students along with them who are in some other class because we have 100% free classes from kindergarten to class 12 so all the students from kindergarten to class 12 can come and study on our channel and do subscribe our channel so that all the recent updates related to your class, subject everything will reach you immediately now I will meet you in our next video, till then stay happy, stay healthy.

Thank you so much.