1 00:00:05,870 --> 00:00:06,589 2 00:00:06,589 --> 00:00:10,320 Around 600 BC Thales of Miletus 3 00:00:10,320 --> 00:00:13,379 widely regarded as the first Greek philosopher. 4 00:00:13,379 --> 00:00:17,650 As he was the first to be purely natural explanation 5 00:00:17,650 --> 00:00:24,650 of the phenomena he observed. A key observations 6 00:00:25,060 --> 00:00:28,430 he made was that certain stones such as amber 7 00:00:28,430 --> 00:00:31,940 when rubbed against fur would exhibit a strange 8 00:00:31,940 --> 00:00:35,610 property. The amber seem to emit an invisible force 9 00:00:35,610 --> 00:00:40,460 which would attract small fibers. 10 00:00:40,460 --> 00:00:44,750 And he assumed that this rendered amber magnetic another force he observed when 11 00:00:44,750 --> 00:00:45,989 playing with lodestone 12 00:00:45,989 --> 00:00:52,200 which are naturally-occurring magnets. Many after him observed that the 13 00:00:52,200 --> 00:00:56,140 contact or friction with fur seem to create an imbalance. 14 00:00:56,140 --> 00:01:00,059 Something was pulled from the fur and transferred onto other objects. 15 00:01:00,059 --> 00:01:06,119 Now, not only did this result in a small attractive or repulsive force 16 00:01:06,119 --> 00:01:09,759 but also in the potential for shocks to occur. 17 00:01:09,759 --> 00:01:13,469 Once the discharge occurred the force disappeared. 18 00:01:13,469 --> 00:01:18,590 So the shock with some form of discharge which reversed the imbalance created by 19 00:01:18,590 --> 00:01:19,389 the friction. 20 00:01:19,389 --> 00:01:25,039 Throughout history we're also fascinated with lightning bolts. 21 00:01:25,039 --> 00:01:30,459 Nature's most passionate displays of power and aggression. 22 00:01:30,459 --> 00:01:33,719 Most cultures assume this was a divine force 23 00:01:33,719 --> 00:01:37,729 outside the reach of human hands and was therefore reserved for the gods. 24 00:01:37,729 --> 00:01:43,689 Up until the 17th century, our descriptions of it varied from an 25 00:01:43,689 --> 00:01:47,359 invisible, intangible, imponderable agent 26 00:01:47,360 --> 00:01:51,340 or even threads of syrup which along gate and contract. 27 00:01:51,340 --> 00:01:58,340 And it was Benjamin Franklin, who in 1752 set out to prove that there is a connection 28 00:01:58,399 --> 00:02:02,179 between lightning and this tiny shocks due to friction. 29 00:02:02,179 --> 00:02:06,649 In a famously dangerous experiment 30 00:02:06,649 --> 00:02:11,200 done alone with his son, he let a kite into a thunderstorm and 31 00:02:11,200 --> 00:02:14,200 near the bottom where the thread was wet, 32 00:02:14,200 --> 00:02:17,310 he tied an iron key and after some time 33 00:02:17,310 --> 00:02:21,569 he brought his knuckle up to the key experienced the series of small shocks 34 00:02:21,569 --> 00:02:25,769 identical to the ones created by contact with fur. 35 00:02:25,769 --> 00:02:29,849 This showed that indeed, lightning was simply the same thing is these household shocks 36 00:02:30,510 --> 00:02:35,930 but on a massive scale. And at this time people have begun to divide materials 37 00:02:35,930 --> 00:02:37,360 into two categories: 38 00:02:37,360 --> 00:02:41,739 one were objects which would allow or accept discharge 39 00:02:41,739 --> 00:02:46,269 such as gold or copper which we call electrical conductors. 40 00:02:46,269 --> 00:02:51,189 Interestingly these materials are also generally good at conducting heat. 41 00:02:51,189 --> 00:02:56,530 And number two were objects which would not allow this discharge such as 42 00:02:56,530 --> 00:02:59,730 rubber or electrical insulators. 43 00:02:59,730 --> 00:03:03,480 These materials also seem to insulate the transfer of heat 44 00:03:03,480 --> 00:03:06,989 and we also began trying to measure this 45 00:03:06,989 --> 00:03:12,159 force that Thales had encountered. One way to do this was to suspend the 46 00:03:12,540 --> 00:03:16,140 piece of spongy plant called the pith ball from a thread 47 00:03:16,140 --> 00:03:20,129 and when we're up in insulator against fur and brought it near the pith 48 00:03:20,129 --> 00:03:23,329 ball it would pole on it 49 00:03:23,329 --> 00:03:30,329 causing a deflection. 50 00:03:31,459 --> 00:03:34,860 If we had more objects we noticed the fraction increased 51 00:03:34,860 --> 00:03:40,660 due to a greater pulling force. 52 00:03:43,299 --> 00:03:46,640 We also noticed that the shape of an insulators made a difference. 53 00:03:46,640 --> 00:03:53,640 Large thin insulators seem to exhibit a much stronger force. 54 00:03:54,440 --> 00:03:59,120 (soft bell ring) 55 00:03:59,120 --> 00:04:01,800 And amazingly, it was found that conductors such as copper 56 00:04:01,800 --> 00:04:04,900 wire would transmit this pulling effect over a distance. 57 00:04:04,900 --> 00:04:09,510 This was demonstrated by running a long wire 58 00:04:09,510 --> 00:04:16,510 between the pith ball in the charged insulator. 59 00:04:16,750 --> 00:04:17,940 When the object was brought near the wire 60 00:04:17,940 --> 00:04:22,120 it pulled through the wire and deflected the pith ball instantly. 61 00:04:22,120 --> 00:04:26,380 When we later touched the wire with our finger 62 00:04:26,380 --> 00:04:30,620 discharge occurs and the pulling stops and the ball is released. 63 00:04:30,620 --> 00:04:35,090 Immediately people began speculating that this could be the future 64 00:04:35,090 --> 00:04:42,090 optical telegraph. In 1774 French inventor George Louis Le Sage 65 00:04:42,100 --> 00:04:45,550 was one of the first one to record actually set up this idea. 66 00:04:45,550 --> 00:04:48,880 He sent messages through an array of 26 wires 67 00:04:48,880 --> 00:04:53,800 each wire representing a letter of the alphabet. When a discharge occurred at 68 00:04:53,800 --> 00:04:56,819 one end the pith ball would move at the other. 69 00:04:56,819 --> 00:05:00,460 The trouble with this telegraph was that it only extended between the two rooms of his house. 70 00:05:01,360 --> 00:05:04,809 The power the deflection was small and difficult to work with. 71 00:05:04,809 --> 00:05:07,930 Though at the time people were investigating techniques for generating 72 00:05:07,930 --> 00:05:10,370 larger charge differences 73 00:05:10,370 --> 00:05:14,080 in order to amplified a force involved. One improvement 74 00:05:14,080 --> 00:05:17,279 popularized by Alessandro Volta one year later 75 00:05:17,279 --> 00:05:21,379 was an easy wave generating discharges on demand. 76 00:05:21,379 --> 00:05:24,559 It was based on the idea that a charged insulator 77 00:05:24,559 --> 00:05:27,969 could induce or transfer the charge onto a nearby 78 00:05:27,969 --> 00:05:32,110 conducting plate. One needed to merely bring the metal plate close to the insulator 79 00:05:32,990 --> 00:05:36,330 which would pull on the charge distribution in the metal plate 80 00:05:36,330 --> 00:05:40,490 resulting in an imbalance or electrical tension in the metal plate. 81 00:05:40,490 --> 00:05:44,360 Then want to bring their finger to the plate in it discharge would occur 82 00:05:44,360 --> 00:05:47,779 then the plate is pulled away using insulating handle 83 00:05:47,779 --> 00:05:52,059 and an access charge would remain trapped in the plate 84 00:05:52,059 --> 00:05:56,289 to play could then be discharged at will simply by touching it to a conductors 85 00:05:56,289 --> 00:05:57,159 such as a finger 86 00:05:57,159 --> 00:06:01,479 and amazingly this process can be repeated many times without recharging 87 00:06:01,479 --> 00:06:03,020 the insulating plate. 88 00:06:03,020 --> 00:06:06,439 We could then generate many small discharges at will. 89 00:06:06,439 --> 00:06:11,589 And by now Benjamin Franklin was focused on finding out how to trap or store up 90 00:06:11,589 --> 00:06:12,879 these discharges. 91 00:06:12,879 --> 00:06:17,020 At this time he still assumed that electricity with some sort of invisible fluid 92 00:06:17,779 --> 00:06:21,029 Since we knew it could travel through water so we assume that 93 00:06:21,029 --> 00:06:25,479 water inside in insulator could hold electricity. 94 00:06:25,479 --> 00:06:28,709 What we now call the laid in jar was a glass jar 95 00:06:28,709 --> 00:06:32,050 with water inside and a metal probe running at the top. 96 00:06:32,050 --> 00:06:35,939 Franklin also wrapped the outside in a conductive metal. 97 00:06:35,939 --> 00:06:42,389 When he brought a charge conductor towards the top probe 98 00:06:42,389 --> 00:06:46,180 a discharge would occur and stay trapped in the jar. 99 00:06:46,180 --> 00:06:50,699 More importantly was that the jar could be charged multiple times. 100 00:06:50,699 --> 00:06:54,289 Each spark would amplify the charge separation 101 00:06:54,289 --> 00:06:58,559 for electrical tension inside the jar. A good analogy is to think of the 102 00:06:58,559 --> 00:06:59,719 jar as a balloon 103 00:06:59,719 --> 00:07:03,120 and each discharge as a short jolt water. 104 00:07:03,120 --> 00:07:06,879 And after 100 iterations the tension become massive. 105 00:07:13,060 --> 00:07:14,810 And to release the charge 106 00:07:14,810 --> 00:07:18,150 he simply touch the outside conductor 107 00:07:18,150 --> 00:07:23,380 to the probe. A large discharge occurred. 108 00:07:23,380 --> 00:07:27,070 Franklin improved the design over time 109 00:07:27,070 --> 00:07:30,610 eventually realizing that the charge was not stored in the water 110 00:07:30,610 --> 00:07:35,590 but glass. The water was merely a conductor path from the probe 111 00:07:35,590 --> 00:07:39,340 to the jar. Today we would call the laid in jar a capacitor 112 00:07:39,340 --> 00:07:44,340 or charge storing device. And when he changed many jars together he founded 113 00:07:44,340 --> 00:07:48,720 increase the capacity even more and release deadly volt of electricity. 114 00:07:48,720 --> 00:07:53,180 And over the years people focused on more effective ways a building up charge using 115 00:07:53,580 --> 00:07:57,320 friction machines which could then be stored in capacitors 116 00:07:57,320 --> 00:08:01,070 and relief the spectacular displays of man-made lightning. 117 00:08:01,070 --> 00:08:08,070 118 00:08:13,440 --> 00:08:20,080 119 00:08:20,080 --> 00:08:25,270 And over the next 50 years people 120 00:08:25,270 --> 00:08:28,330 tried to design systems for sending sparks 121 00:08:28,330 --> 00:08:35,330 across greater distances using longer wires and more powerful discharges. 122 00:08:35,870 --> 00:08:40,380 However sending electrostatic discharges as a communication method 123 00:08:40,380 --> 00:08:44,770 seemed clumsy archaic and was no improvement over the existing 124 00:08:44,770 --> 00:08:48,120 optical telegraph of the day. 125 00:08:48,120 --> 00:08:51,630 They were widely ignored by government and industry. 126 00:08:51,630 --> 00:08:54,900 Though the tides were rising. 127 00:08:54,900 --> 00:00:00,000 An electric revolution was just around the corner.