1 00:00:03,180 --> 00:00:25,679 Well, after writing, planning, it's a good idea to retake or review the different contents about materials and tools and I think we are going to do now. 2 00:00:25,679 --> 00:00:47,240 It's important to know what is materials in technology. After that, we are going to explain the classification of materials and the properties of them. 3 00:00:47,240 --> 00:01:00,200 and we'll do a small description about some of the most important materials 4 00:01:01,320 --> 00:01:10,840 and after that I'm going to summarize 5 00:01:10,840 --> 00:01:27,900 The main thing that usually we do in the workshop, when we are building our projects, are the 6 00:01:27,900 --> 00:01:37,079 tools that usually we use and more or less workshop. 7 00:01:37,079 --> 00:02:12,569 Firstly, obviously everything is made by materials. Things have a shape, a three-dimensional shape and to do these shapes we need different parts. 8 00:02:12,569 --> 00:02:18,569 and each part is made with a typical material 9 00:02:18,569 --> 00:02:27,569 nowadays for example plastics are very used in different things 10 00:02:27,569 --> 00:02:30,569 for so many things 11 00:02:30,569 --> 00:02:38,569 that is that materials indeed aren´t just only one substance 12 00:02:38,569 --> 00:02:42,569 usually are a mixture of different substances 13 00:02:42,569 --> 00:02:54,569 A substance is mainly formed by just only one type of molecule 14 00:02:54,569 --> 00:03:16,810 and as you know the molecules are formed, are being, are being by the joint of different atoms 15 00:03:16,810 --> 00:03:32,870 so the complexity the material are very complex but this complexity is made by 16 00:03:32,870 --> 00:03:46,090 misters of simple things the particles such as electron or proton of neutron 17 00:03:46,090 --> 00:03:56,620 can be part of an atom 18 00:03:56,620 --> 00:04:06,620 and the joint of different atoms with the different chemical link 19 00:04:06,620 --> 00:04:10,620 make the substance 20 00:04:10,620 --> 00:04:21,660 and the mixture of different substance, in general, can form part of different materials, 21 00:04:21,660 --> 00:04:34,819 different technical materials. So, indeed, materials are very complex. In order to easy 22 00:04:34,819 --> 00:04:46,060 our study we will classify materials into two main categories which are 23 00:04:46,060 --> 00:04:56,050 methods and non-methods. There are more than one classification. This is one of 24 00:04:56,050 --> 00:05:16,769 the most important, but other possibility would be into structural and functional materials 25 00:05:16,769 --> 00:05:21,949 and it is also a technical classification. 26 00:05:21,949 --> 00:05:31,810 Well, return to the main idea, materials can be classified into two different groups, which 27 00:05:31,810 --> 00:05:34,569 are metals and non-metals. 28 00:05:34,569 --> 00:05:46,050 Obviously, it is very easy to distinguish a metal and it is the main reason why we use 29 00:05:46,050 --> 00:05:49,290 this kind of classification. 30 00:05:49,290 --> 00:06:05,170 Another good reason is because the methyl link has a very specific and typical properties 31 00:06:05,170 --> 00:06:11,810 as we will describe later. 32 00:06:11,810 --> 00:06:22,050 Then methods can also be divided into ferrows and noferrows. 33 00:06:22,050 --> 00:06:46,129 Well, indeed, there aren't any methods with 100% of the technical materials usually are 34 00:06:46,129 --> 00:06:59,649 the solutions of a metal with other metals or no metals and it is very important to know. 35 00:06:59,649 --> 00:07:15,370 When I say that a material is a metal, I'm saying really indeed that it is a dissolution 36 00:07:15,370 --> 00:07:25,769 which metal is solvent. So we can distinguish ferrous and noferrous. 37 00:07:25,769 --> 00:07:40,129 In ferrous the solvent is iron but the other substance usually is carbon and if the 38 00:07:40,129 --> 00:07:57,920 the quantity of carbon is less than 2% then this is a steel, otherwise it is a steel. 39 00:07:57,920 --> 00:08:10,560 To know Ferreira's materials, we can classify into two categories, which are light if its 40 00:08:10,560 --> 00:08:27,680 density is less than titanium, or heavy if its density is higher than titanium. 41 00:08:27,680 --> 00:08:37,440 category one example of life category would be a titanium and also aluminium 42 00:08:37,440 --> 00:08:50,519 one example one example of heavy could be a copper and its alloys such as 43 00:08:50,519 --> 00:09:02,809 bronze and brass. For non-metals materials there isn't any any good classification. 44 00:09:06,090 --> 00:09:20,730 People usually classify using their main uses, for example materials for buildings or material 45 00:09:20,730 --> 00:09:39,450 for clothes or materials for other things. I classify non-metals into two good categories 46 00:09:39,450 --> 00:09:48,889 which are natural and synthetic. Obviously natural aren't not so natural 47 00:09:48,889 --> 00:10:07,450 Because, for example, marble or granite or clay usually are understood as natural materials. 48 00:10:07,450 --> 00:10:23,929 But obviously, when I use one of these materials, it's not a raw material, it's a processed 49 00:10:23,929 --> 00:10:25,870 material. 50 00:10:25,870 --> 00:10:37,210 So it's the point, the characteristic of technology. 51 00:10:37,210 --> 00:10:59,169 And synthetic materials are made in a laboratory, so they aren't in the nature. 52 00:10:59,169 --> 00:11:04,909 You can find them in the nature. 53 00:11:04,909 --> 00:11:15,529 For natural materials we can classify them into two different categories which are organic 54 00:11:15,529 --> 00:11:33,950 and inorganic and for synthetic materials also we classify into organic and inorganic. 55 00:11:33,950 --> 00:11:45,519 The importance of the materials are because their properties and because they are used 56 00:11:45,519 --> 00:11:52,960 in technological work and the uses are connected with their properties. 57 00:11:52,960 --> 00:12:06,799 So we can classify the properties into three main categories, which are mechanical, physical 58 00:12:06,799 --> 00:12:09,559 and chemical. 59 00:12:09,559 --> 00:12:20,139 One example of mechanical property could be a breaking strength or elasticity. 60 00:12:20,139 --> 00:12:34,200 For physical properties, it could be a good example, density and conductivity. 61 00:12:34,200 --> 00:12:43,139 And finally, for chemical properties, a good example, obviously, is the composition of 62 00:12:43,139 --> 00:12:44,139 these materials. 63 00:12:44,139 --> 00:13:03,500 Obviously it is very important to do a good selection of material, because each material has its own property, 64 00:13:03,500 --> 00:13:13,500 so you can focus on just one specific application of this material. 65 00:13:13,500 --> 00:13:24,500 For example, there are a lot of materials such as metals that are usually used in structural applications. 66 00:13:24,500 --> 00:13:34,500 Whereas you also have other materials such as copper that is very important for electricity applications. 67 00:13:34,500 --> 00:13:50,500 So, nowadays we can combine different materials to do composite materials and this is one advantage and one advantage of material science. 68 00:13:50,500 --> 00:14:00,500 But indeed there isn't the best material, there isn't the perfect material for all uses. 69 00:14:00,500 --> 00:14:09,559 so you can analyze in each case which is the best materials in each case and this 70 00:14:09,559 --> 00:14:22,440 is a very important and very difficult activity for science well connected what 71 00:14:22,440 --> 00:14:29,720 I have said before in in this slide you can compare three types of materials 72 00:14:29,720 --> 00:14:36,519 that are very useful and I don't know they say they are the most useful ones 73 00:14:36,519 --> 00:14:45,080 and you can analyze the good properties and the bad properties in order to can 74 00:14:45,080 --> 00:14:52,279 choose which is the best of all for one specific application of this material 75 00:14:52,279 --> 00:15:00,340 And this is the end of the first introduction to material science. 76 00:15:00,340 --> 00:15:10,320 What you need to do now is the exercise that I proposed to you because it is the only way 77 00:15:10,320 --> 00:15:15,519 that you can understand all of this complex content. 78 00:15:15,519 --> 00:15:24,519 I'll see you. This is the end, so I hope you can enjoy it and you can learn. 79 00:15:24,519 --> 00:15:32,519 Today, that is all. Now we are going to do the activities.