1 00:00:00,180 --> 00:00:06,299 Hello kids! Today, in social science, we are going to learn about imaginary lines. 2 00:00:07,099 --> 00:00:16,739 As you can see, in this globe, there are many lines, but they are not drawn on the Earth's ground or on water. 3 00:00:17,899 --> 00:00:25,039 They are invisible, so we can't see them. But what are these imaginary lines for? 4 00:00:25,039 --> 00:00:37,899 On maps and globes, there are invisible lines, imaginary lines, that we use to describe a location on the Earth's surface to find a place on Earth. 5 00:00:38,299 --> 00:00:44,799 So, they tell us where exactly a place is on the Earth's surface. 6 00:00:46,179 --> 00:00:51,200 Imaginary lines are very useful for pilots when they are flying a plane. 7 00:00:52,060 --> 00:00:54,280 They use imaginary lines. 8 00:01:02,109 --> 00:01:12,510 So, this pilot knows he has to go to that green point, but how can he go there? 9 00:01:12,769 --> 00:01:18,909 There are not signs floating in the air, there are not stop signs, right and left signs. 10 00:01:18,909 --> 00:01:23,069 For that, he uses imaginary lines. 11 00:01:23,969 --> 00:01:29,310 So, he knows he has to go to the east, but where exactly? 12 00:01:29,310 --> 00:01:40,370 northeast or southeast the imaginary lines will help him there are two types of imaginary lines 13 00:01:40,370 --> 00:01:49,829 longitude lines which are long they are long and they go from the north pole to the south pole 14 00:01:49,829 --> 00:01:58,290 they run north to south so they are vertical lines and latitude lines 15 00:01:58,290 --> 00:02:08,090 latitude lines are lateral they run east to west they are horizontal lines 16 00:02:08,090 --> 00:02:19,409 let's start with lines of longitude which are also called meridians as i said before they are 17 00:02:19,409 --> 00:02:27,090 vertical they are long and they run north to south but let's find out more about them 18 00:02:27,090 --> 00:03:24,939 so as you can see there are many lines of longitude and as he said to identify them 19 00:03:24,939 --> 00:03:31,719 we number them and the main meridian the meridian in the center is the prime meridian 20 00:03:31,719 --> 00:03:39,300 this meridian is also called greenwich the greenwich meridian because it passes through 21 00:03:39,300 --> 00:03:47,840 the city of Greenwich in the United Kingdom and it's the zero degrees meridian but what's that 22 00:03:47,840 --> 00:03:56,900 what's a degree in this case degree is not temperature it's a unit of measure which 23 00:03:56,900 --> 00:04:04,759 measures how far away we are from the center one degree is 111 kilometers zero degrees is the 24 00:04:04,759 --> 00:04:15,319 center and we can move away to the east 10 degrees east 20 degrees east and so on 30 degrees east 40 25 00:04:15,319 --> 00:04:22,860 degrees east but we can also move away to the west 10 degrees west 20 degrees west so meridians 26 00:04:22,860 --> 00:04:32,019 measure distances east and west this is meridian 10 degree east and meridian 10 degree west 27 00:04:32,899 --> 00:04:34,740 Okay, let's sum up. 28 00:04:37,540 --> 00:04:42,740 As I said before, meridians are vertical lines that run north to south, 29 00:04:43,139 --> 00:04:47,519 and they measure distances east and west. 30 00:04:48,480 --> 00:04:53,560 So, we know that one degree is 111 kilometers. 31 00:04:53,560 --> 00:05:03,180 If we need to find out how far away the 20-degree east meridian is from the center, 32 00:05:03,180 --> 00:05:16,939 from the Greenwich Meridian, we have to multiply 20 times 111 kilometers, that's 33 00:05:16,939 --> 00:05:29,379 2220 kilometers away from the center. Is it enough information for the pilot to 34 00:05:29,379 --> 00:05:43,970 know where he has to go let's see no it's not enough because he knows that he 35 00:05:43,970 --> 00:05:52,009 has to go 30 degrees away from the center to the east but does he have to 36 00:05:52,009 --> 00:06:02,750 go down there or up there he also needs the information of lines of latitude 37 00:06:02,750 --> 00:06:12,129 which are also called parallels. As I said before, parallels are horizontal 38 00:06:12,129 --> 00:06:24,100 lines that run east to west and let's find out more about them. 39 00:06:24,100 --> 00:07:04,860 So again there are many parallels, many lines of latitude and 40 00:07:04,860 --> 00:07:08,819 And to identify them, we number them. 41 00:07:10,360 --> 00:07:13,100 The main parallel is in the center. 42 00:07:13,800 --> 00:07:17,860 It's zero degrees, and it's also called the equator. 43 00:07:18,759 --> 00:07:25,800 So, the equator is in the center, and we can move away from the equator to the north or to the south. 44 00:07:25,800 --> 00:07:40,310 So, for example, we can see in this globe that the North Pole is 90 degrees north. 45 00:07:40,829 --> 00:07:48,290 It means that it's 90 degrees away from the equator and it's to the north. 46 00:07:51,589 --> 00:07:57,850 And to sum up, we can say that parallels are horizontal lines that run east to west 47 00:07:57,850 --> 00:08:02,490 and they measure distances north and south. 48 00:08:08,699 --> 00:08:11,379 Now the pilot has enough information. 49 00:08:12,339 --> 00:08:16,899 He's going 20 degrees north and 30 degrees east. 50 00:08:17,139 --> 00:08:19,639 That's a geographic coordinate. 51 00:08:23,550 --> 00:08:26,589 So 1 degree is 111 kilometers 52 00:08:26,589 --> 00:08:30,329 and he's going 20 degrees north. 53 00:08:30,329 --> 00:08:34,909 So we have to multiply 20 times 111. 54 00:08:34,909 --> 00:08:41,289 That's 2,220 kilometers away from the center, from the equator. 55 00:08:41,909 --> 00:08:45,450 And he also has to go 30 degrees east. 56 00:08:45,990 --> 00:08:49,169 That's 30 times 111. 57 00:08:50,830 --> 00:08:57,870 3,330 kilometers away from the center, from the Greenwich Meridian. 58 00:08:58,649 --> 00:09:02,730 Now the pilot knows exactly where he's going. 59 00:09:02,730 --> 00:09:05,149 ok, this is it 60 00:09:05,149 --> 00:09:07,090 I hope you understood it 61 00:09:07,090 --> 00:09:08,730 and now you have to practice 62 00:09:08,730 --> 00:09:09,730 bye bye