1 00:00:04,530 --> 00:00:26,129 Hello, guys. As you remember, we are in the electricity unit. We have started this unit already in December. But, well, I know that Christmas has passed and everything. So, before we continue with the unit, I'm going to remind you what we have seen, okay? 2 00:00:26,129 --> 00:00:34,289 and I know that we used another presentation in December and it was fine 3 00:00:34,289 --> 00:00:43,570 but I think this this presentation is more complete and well I think it's 4 00:00:43,570 --> 00:00:49,950 going to be easier for you to to understand the electricity unit okay so 5 00:00:49,950 --> 00:00:51,909 So here we go. 6 00:00:51,909 --> 00:00:57,270 The first thing that we need to remember is what is electricity. 7 00:00:57,270 --> 00:01:03,570 Remember that the first day I told you that matter is formed by atoms. 8 00:01:03,570 --> 00:01:08,290 You remember matter means materia and materia is anything. 9 00:01:08,290 --> 00:01:14,390 You are matter, myself is matter, an animal is matter, an object is matter, everything 10 00:01:14,390 --> 00:01:19,189 that you know, that everything that you can touch is matter, okay? 11 00:01:19,189 --> 00:01:22,230 This matter is formed by very small particles 12 00:01:22,230 --> 00:01:24,150 that are called atoms. 13 00:01:24,150 --> 00:01:28,430 And they have, they contain inside smaller particles 14 00:01:28,430 --> 00:01:31,930 with electrical charges that are called atoms. 15 00:01:32,849 --> 00:01:33,750 Remember that? 16 00:01:34,790 --> 00:01:39,069 We have outside electrons that are charged negatively 17 00:01:39,069 --> 00:01:43,849 and inside protons that are charged positively 18 00:01:43,849 --> 00:01:46,810 and neutrons that are charged, 19 00:01:46,810 --> 00:01:49,629 but that don't have a charge, okay? 20 00:01:55,069 --> 00:01:57,629 This charge create forces between them 21 00:01:57,629 --> 00:02:00,629 that can be attraction or repulsion 22 00:02:00,629 --> 00:02:02,890 according to the value of the charge, remember? 23 00:02:02,890 --> 00:02:04,909 If we have different charges, 24 00:02:04,909 --> 00:02:07,510 we are going to get an attraction 25 00:02:07,510 --> 00:02:09,349 and we have equal charges, 26 00:02:09,349 --> 00:02:12,710 we are going to get a repulsion, repulsion and repulsion. 27 00:02:12,710 --> 00:02:15,569 It doesn't matter if the charges are positive or negative, 28 00:02:15,569 --> 00:02:18,939 we're going to have repulsion. 29 00:02:18,939 --> 00:02:20,979 So what is electricity? 30 00:02:20,979 --> 00:02:26,360 here look look at this picture we have different atoms that are together this 31 00:02:26,360 --> 00:02:31,300 is what it happens with matter in mind is your arm your head your feet your 32 00:02:31,300 --> 00:02:37,300 foot so we have the atoms very close together and electrons are moving from 33 00:02:37,300 --> 00:02:41,620 one from this atom to this to the other from the other to the other and the 34 00:02:41,620 --> 00:02:49,900 movement of these electrons with the atoms is electricity so if I ask you 35 00:02:49,900 --> 00:03:07,400 So, what is electricity? Electricity is the movement of an electron from one atom to another, right? Okay. However, well, we have seen that electrons travel from one atom to another, okay? 36 00:03:07,400 --> 00:03:24,699 But if we want, for example, electrons to travel from a battery to a light, we are going to need a wire made of a material that allows the pass of the electrons. 37 00:03:25,819 --> 00:03:30,280 These materials that allow the pass of the electrons are called conductors. 38 00:03:31,360 --> 00:03:33,020 And we have metals or water. 39 00:03:33,620 --> 00:03:34,919 They transmit electricity. 40 00:03:34,919 --> 00:03:38,759 Remember the wires are normally made of copper 41 00:03:38,759 --> 00:03:40,500 because it's a very good conductor. 42 00:03:40,500 --> 00:03:45,240 They allow the pass of the current. 43 00:03:45,240 --> 00:03:47,919 Other materials don't allow the electrons to move. 44 00:03:47,919 --> 00:03:52,300 These are called insulators, for example, wood or plastic. 45 00:03:52,300 --> 00:03:56,439 In those materials, if we put imagine a battery 46 00:03:56,439 --> 00:04:00,520 and a light and we put a wood in between, 47 00:04:00,520 --> 00:04:04,039 electricity is not going to pass, okay? 48 00:04:04,039 --> 00:04:05,639 They are insulators. 49 00:04:06,639 --> 00:04:09,719 Okay, remember we did this experiment. 50 00:04:09,719 --> 00:04:12,060 We created static electricity. 51 00:04:12,060 --> 00:04:16,560 Here we can also see the repulsion and attraction rules. 52 00:04:17,699 --> 00:04:21,439 We got our sweater and we got a pen. 53 00:04:21,439 --> 00:04:23,779 We wrapped the pen on the cloth. 54 00:04:23,779 --> 00:04:26,459 So what happened was that the electrons, 55 00:04:26,459 --> 00:04:31,459 the negative charge of the sweater went to the pen, okay? 56 00:04:31,459 --> 00:04:39,540 pen okay and then when we put the pen when we touch the pen with the paper and the positive 57 00:04:39,540 --> 00:04:46,899 charges of the paper are going to travel and meet within with the pen because they are attracted 58 00:04:46,899 --> 00:04:52,500 they have different charges we have the electrons of the pen here and the positive charges of the 59 00:04:52,500 --> 00:04:57,300 of the of the paper and they are going to be attracted because they have different 60 00:04:57,300 --> 00:05:03,420 sign however the negative part of the paper are going to be repelled did you 61 00:05:03,420 --> 00:05:09,540 remember with experiment not all the paper was attached to the pen not all 62 00:05:09,540 --> 00:05:15,480 the paper only one part the part that was attached was only the part that had 63 00:05:15,480 --> 00:05:24,360 different charges okay remember that okay so how electricity is created and 64 00:05:24,360 --> 00:05:30,720 transform remember that a battery the batteries that we have been using in our 65 00:05:30,720 --> 00:05:42,410 experiments has a pole with negative charge and when we connect well the 66 00:05:42,410 --> 00:05:46,610 battery has a pole with more negative charges so when we connect them we 67 00:05:46,610 --> 00:05:52,629 connect the negative charges of a battery we create a balance we create we 68 00:05:52,629 --> 00:05:54,370 We connect the charges and start moving 69 00:05:54,370 --> 00:05:56,509 in order to balance themselves. 70 00:05:56,509 --> 00:05:58,850 We can read the electrical current. 71 00:05:58,850 --> 00:06:03,709 So the flow of the electrons go from the negative pole 72 00:06:03,709 --> 00:06:06,370 to the positive creating electrical current 73 00:06:06,370 --> 00:06:09,649 because of this difference, because of the balance. 74 00:06:11,069 --> 00:06:12,730 Okay, so here we have a circuit. 75 00:06:12,730 --> 00:06:16,689 We have our battery and one of our lights, a wire 76 00:06:16,689 --> 00:06:19,889 and inside the wire is the movement of the electrons. 77 00:06:19,889 --> 00:06:21,589 So we have the battery. 78 00:06:21,589 --> 00:06:25,149 they have, well, the battery has energy 79 00:06:25,149 --> 00:06:28,329 and energy is going to allow the electrons to travel. 80 00:06:28,329 --> 00:06:32,069 They are going to go outside the battery. 81 00:06:32,069 --> 00:06:35,129 They're going to go outside from the negative pole. 82 00:06:35,129 --> 00:06:36,269 They're going to travel 83 00:06:37,209 --> 00:06:40,850 and they are going to go back to the battery, 84 00:06:40,850 --> 00:06:43,110 to the positive pole. 85 00:06:43,110 --> 00:06:46,829 And the movement is creating electrical current. 86 00:06:48,069 --> 00:06:51,490 Okay, remember that what we have seen in practice one 87 00:06:51,490 --> 00:06:55,509 is that when the electrons travel along the wire 88 00:06:55,509 --> 00:07:00,509 and if in the path they encounter something, 89 00:07:00,949 --> 00:07:05,910 for example, a bulb, the electrons touch the bulb, 90 00:07:05,910 --> 00:07:07,769 the bulb is going to light. 91 00:07:07,769 --> 00:07:12,370 Okay, if we don't have a bulb but we have a fan, 92 00:07:12,370 --> 00:07:13,709 the fan is going to move. 93 00:07:13,709 --> 00:07:15,769 If we have a motor, it's going to move. 94 00:07:15,769 --> 00:07:19,870 If we have a toaster, for example, it's going to work. 95 00:07:19,870 --> 00:07:23,910 So the electricity is created with the battery 96 00:07:23,910 --> 00:07:25,649 or with electrical power 97 00:07:25,649 --> 00:07:28,189 and it's transformed into calorific energy, 98 00:07:28,189 --> 00:07:31,930 mechanical energy, light energy, magnetic energy and so on. 99 00:07:32,949 --> 00:07:36,769 And that is the reason why the light, 100 00:07:36,769 --> 00:07:42,310 why the bulb worked. 101 00:07:42,310 --> 00:07:46,230 Okay, so imagine we have the atoms 102 00:07:46,230 --> 00:07:48,170 and the electrons travel. 103 00:07:48,170 --> 00:07:52,870 Okay, travel inside the wire. 104 00:07:52,870 --> 00:07:55,829 So electrical current, electric current is the displacement 105 00:07:55,829 --> 00:08:03,939 of the electrical charges through the matter, okay? 106 00:08:03,939 --> 00:08:07,319 Remember in the summer, we also see the voltage. 107 00:08:10,480 --> 00:08:13,100 Well, the electron needs energy to be able to move 108 00:08:13,100 --> 00:08:15,660 through a material, this is the voltage. 109 00:08:15,660 --> 00:08:17,839 Okay, so the battery has an energy 110 00:08:17,839 --> 00:08:19,920 that is called the voltage. 111 00:08:19,920 --> 00:08:22,819 And the voltage is the energy per charge unit 112 00:08:22,819 --> 00:08:26,800 that makes them to flow in through a material, okay? 113 00:08:26,800 --> 00:08:28,339 We have the battery here. 114 00:08:28,339 --> 00:08:31,800 It has energy is going to impulse the electrons 115 00:08:31,800 --> 00:08:35,220 to go outside and to travel along the wire. 116 00:08:35,220 --> 00:08:39,179 This magnitude is measuring volts, okay? 117 00:08:39,179 --> 00:08:40,879 And with the voltage, 118 00:08:40,879 --> 00:08:43,919 it happens something similar to water, okay? 119 00:08:43,919 --> 00:08:45,919 If we have higher voltage, 120 00:08:45,919 --> 00:08:48,600 imagine that, well, this is the battery. 121 00:08:48,600 --> 00:08:53,159 we have a lot of electrons and if we open the wire, 122 00:08:53,159 --> 00:08:54,720 we are going to have more pressure, 123 00:08:54,720 --> 00:08:57,379 more water pressure and more electrons here. 124 00:08:57,379 --> 00:09:01,980 If the voltage is lower or the water is lower, 125 00:09:01,980 --> 00:09:03,580 we are going to have less pressure here 126 00:09:03,580 --> 00:09:06,200 and less water here, less electrons. 127 00:09:06,200 --> 00:09:08,799 That happens the same with the batteries. 128 00:09:08,799 --> 00:09:10,620 If we have a higher voltage, 129 00:09:10,620 --> 00:09:12,480 more electrons are going to travel. 130 00:09:12,480 --> 00:09:15,759 We have lower voltage, less electrons are going to travel. 131 00:09:15,759 --> 00:09:18,500 That's what it happened in practice one. 132 00:09:18,500 --> 00:09:19,940 with different batteries. 133 00:09:19,940 --> 00:09:21,980 The battery with the highest voltage, 134 00:09:24,220 --> 00:09:27,240 the light bulb was, 135 00:09:27,240 --> 00:09:29,059 the light was stronger 136 00:09:29,059 --> 00:09:35,879 than the battery with a lower voltage. 137 00:09:36,039 --> 00:09:39,860 We also have another magnitude, which is called intensity. 138 00:09:39,860 --> 00:09:41,759 Okay, the intensity is the amount of charges 139 00:09:41,759 --> 00:09:43,320 that goes through a conductor. 140 00:09:43,320 --> 00:09:46,299 The amount of electrons is measured in amperes. 141 00:09:46,299 --> 00:09:49,039 For example, here, there are a lot of electrons. 142 00:09:49,039 --> 00:09:50,919 we have higher intensity. 143 00:09:50,919 --> 00:09:57,070 We have here less electrons, we have lower intensity. 144 00:09:57,070 --> 00:10:00,570 And resistance, this is another magnitude. 145 00:10:00,570 --> 00:10:02,649 Remember that in December, 146 00:10:02,649 --> 00:10:04,389 we were discussing about resistance. 147 00:10:04,389 --> 00:10:07,090 I was telling you that you were electrons, 148 00:10:07,090 --> 00:10:08,490 that you were in a classroom 149 00:10:08,490 --> 00:10:11,870 and you wanted to travel from one classroom to another. 150 00:10:11,870 --> 00:10:15,169 And remember that I told you that I was a resistance 151 00:10:15,169 --> 00:10:17,330 and I was in the middle of the door. 152 00:10:17,330 --> 00:10:19,309 So what happened? 153 00:10:19,309 --> 00:10:26,269 if i'm super fat uh not many people are going to 154 00:10:26,269 --> 00:10:31,549 go through the door right because i i don't allow you to pass 155 00:10:31,549 --> 00:10:35,230 however if i'm a slimmer more electrons are going to pass 156 00:10:35,230 --> 00:10:40,909 that's what it happens with electricity we if we have we got if we have higher 157 00:10:40,909 --> 00:10:43,870 resistance we have more elements that are going to 158 00:10:43,870 --> 00:10:46,509 impede the pass of the current okay the 159 00:10:46,509 --> 00:10:52,190 resistance is the opposition of the movement however the if the resistance is lower 160 00:10:53,070 --> 00:10:56,909 uh more electrons are going to pass it's measuring ohms 161 00:10:58,909 --> 00:11:05,629 okay now that we have seen the three magnitudes uh we have the ohm's law the ohm's law is the 162 00:11:05,629 --> 00:11:11,389 load that relates uh the three magnitudes the intensity the voltage and the resistance 163 00:11:12,190 --> 00:11:18,190 this formula is very important that you learn and this table is very important that you learn it 164 00:11:18,190 --> 00:11:24,350 this is going to be on the exam all right we have magnitude and the symbols of it voltage 165 00:11:24,350 --> 00:11:31,070 intensity and resistance have those symbols and the units how they are measured are volts 166 00:11:31,070 --> 00:11:39,789 amperes and ohms and the symbols of the units okay please don't um try to distinguish between 167 00:11:39,789 --> 00:11:46,590 the symbol of the magnitude and the symbol of the unit for example my name is monica and the symbol 168 00:11:46,590 --> 00:11:55,309 of my name is an m however if i want to know my weight is going to measure in kilograms and the 169 00:11:55,309 --> 00:12:04,990 symbol is going to be k okay even though my name and my wage are part of myself uh are different 170 00:12:04,990 --> 00:12:13,549 things we cannot measure my name with an m but we can measure my wage with a with a k that happens 171 00:12:13,549 --> 00:12:18,509 the same we have the name of a magnitude and the name has a symbol and how we measure that 172 00:12:18,509 --> 00:12:28,429 magnitude has another symbol okay all of that is what we have seen in december okay now we are 173 00:12:28,429 --> 00:12:37,950 going to learn what electric circuit has okay we have built some electric circuits in practice one 174 00:12:37,950 --> 00:12:44,669 and practice two and we are going to see which parts they have this is an electrical circuit 175 00:12:44,669 --> 00:12:49,389 we have generators control elements receptor conductor and protection elements 176 00:12:50,029 --> 00:12:58,779 we are going to see what are they okay okay a generator is a component that generates current 177 00:12:58,779 --> 00:13:05,580 okay a battery the symbol is this so if we draw um 178 00:13:05,580 --> 00:13:09,820 if we draw a circuit we need to draw it like this 179 00:13:09,820 --> 00:13:16,940 the battery okay receptors are um with the different objects that 180 00:13:16,940 --> 00:13:20,539 are going to receive the electrons okay and they're and are going to do 181 00:13:20,539 --> 00:13:25,179 something we have the valve for example the symbol is like that if we want to 182 00:13:25,179 --> 00:13:32,700 draw a bulb on a paper we need to draw it like that it produces light when it gets the electrons 183 00:13:32,700 --> 00:13:40,299 a motor it produces motion resistor well here it says it produces heat because some resistors 184 00:13:41,500 --> 00:13:48,379 produce heat okay but other resistors just opposed to the to the to the current okay 185 00:13:49,419 --> 00:13:54,940 we have a buzzer it produces sun you need to learn the different components and the different 186 00:13:54,940 --> 00:14:01,899 symbols and why are they used for okay we also have concert components we have 187 00:14:01,899 --> 00:14:08,139 a switch okay controls the flow of the current so when the switch is closed is 188 00:14:08,139 --> 00:14:13,159 going to allow the pass of the electrons you can see for example you're there we 189 00:14:13,159 --> 00:14:19,480 have electrons here traveling did it if this is closed they can pass they don't 190 00:14:19,480 --> 00:14:23,200 have any hole they can pass however if we open it they are going to be a hole 191 00:14:23,200 --> 00:14:27,759 and electrons are going to be stuck here, they are not going to be able to pass. 192 00:14:27,759 --> 00:14:36,340 A three-way switch, a commutador, is the same as a switch but with two circuits, 193 00:14:36,340 --> 00:14:43,360 so it alternates the flow of the current between two circuits. If we close this switch here, 194 00:14:43,360 --> 00:14:49,840 that means that the electrons are going to pass from here to this circuit and if we close it in 195 00:14:49,840 --> 00:14:53,220 in this direction, electrons are going to pass from here 196 00:14:53,220 --> 00:14:54,779 to this direction. 197 00:14:54,779 --> 00:14:58,460 A push button, it controls the flow of the current 198 00:14:58,460 --> 00:15:00,860 as we have seen in practice two. 199 00:15:00,860 --> 00:15:03,360 When we press the button, we press it, 200 00:15:05,179 --> 00:15:07,940 it happens something similar to the switch. 201 00:15:07,940 --> 00:15:11,299 If we press it, the current is going to flow. 202 00:15:11,299 --> 00:15:12,860 Can you see? 203 00:15:12,860 --> 00:15:14,059 It flows. 204 00:15:14,059 --> 00:15:15,960 However, if we don't push it, 205 00:15:17,120 --> 00:15:19,360 it's going to be very far away. 206 00:15:19,360 --> 00:15:21,039 Imagine that it's a bridge. 207 00:15:21,039 --> 00:15:24,320 If the bridge is not here, it's very far, 208 00:15:24,320 --> 00:15:25,779 you're not going to pass. 209 00:15:25,779 --> 00:15:28,320 However, if it's close, it's going to pass. 210 00:15:28,320 --> 00:15:30,679 Like what it happens with the flow of the current. 211 00:15:30,679 --> 00:15:33,320 And protection components. 212 00:15:33,320 --> 00:15:36,779 They protect the circuit and we have a fuse, 213 00:15:36,779 --> 00:15:41,919 something like that, and this is a symbol, okay? 214 00:15:41,919 --> 00:15:45,000 So I want you to do exercise seven. 215 00:15:45,000 --> 00:15:47,100 I want you to draw the following circuit 216 00:15:47,100 --> 00:15:49,100 using electric symbols. 217 00:15:49,100 --> 00:15:50,720 And exercise eight, 218 00:15:50,720 --> 00:15:53,659 go the following circuit using electric symbols. 219 00:15:53,659 --> 00:15:56,480 If you have any question, just let me know. 220 00:15:56,480 --> 00:15:58,779 You can text me on the chat. 221 00:15:58,779 --> 00:16:01,179 I will be there to answer to your questions.