WEBVTT 1 00:00:01.480 --> 00:00:21.440 [unclear opening audio] 2 00:00:43.880 --> 00:00:44.820 Hey, Adabot. 3 00:00:46.120 --> 00:00:47.880 Have you seen any of my batteries around? 4 00:00:48.220 --> 00:00:49.360 Oh, hi, Ladyada. 5 00:00:49.360 --> 00:00:53.320 I was just thinking about all the energy stored in these batteries, just waiting 6 00:00:53.320 --> 00:00:54.220 to be used. 7 00:00:54.400 --> 00:00:55.940 That's right. Batteries are really cool. 8 00:00:56.160 --> 00:00:58.480 And they're even cooler when they're used to power my multimeter. 9 00:01:04.500 --> 00:01:08.760 Batteries give us electricity on the go without needing to plug into a wall socket. 10 00:01:08.920 --> 00:01:10.680 But there's one thing I don't understand. 11 00:01:10.940 --> 00:01:11.920 What's that, Adabot? 12 00:01:12.320 --> 00:01:15.760 How do we fill batteries up with electricity in the first place? 13 00:01:16.500 --> 00:01:19.880 Well, batteries aren't really filled with electricity. 14 00:01:20.100 --> 00:01:23.760 They're filled with a bunch of components that generate electrical current. 15 00:01:24.360 --> 00:01:26.920 Oh, you mean they have little machines inside? 16 00:01:27.780 --> 00:01:31.440 Hmm, not exactly. I think we should look this one up. 17 00:01:31.820 --> 00:01:34.940 Agreed. Accessing database. Battery. 18 00:01:42.120 --> 00:01:46.620 There are two important parts of every battery, the positive and negative terminal. 19 00:01:55.700 --> 00:01:57.920 And if we opened up a battery, it would look like this. 20 00:02:01.480 --> 00:02:07.740 huh how does that make electricity well a battery uses chemistry to create electricity 21 00:02:07.740 --> 00:02:12.700 is called an electrochemical reaction oh sounds powerful 22 00:02:12.700 --> 00:02:16.600 it definitely is each terminal in a 23 00:02:16.600 --> 00:02:22.420 battery is made of a different kind of material the negative 24 00:02:22.420 --> 00:02:23.920 terminal is made of material that 25 00:02:23.920 --> 00:02:25.900 has a lot of extra electrons in it 26 00:02:25.900 --> 00:02:31.800 it looks 27 00:02:31.800 --> 00:02:33.740 pretty crowded in there it sure 28 00:02:33.740 --> 00:02:37.540 is and all those electrons really want to get some more space they want to go 29 00:02:37.540 --> 00:02:41.100 over to the positive terminal which has a lot of holes so the electrons can fit 30 00:02:41.100 --> 00:02:41.580 into them 31 00:02:41.580 --> 00:02:47.560 it doesn't look 32 00:02:47.560 --> 00:02:50.400 too far can't they just jump to the positive terminal 33 00:02:50.400 --> 00:02:53.720 they can't do that because the battery is filled with a special chemical 34 00:02:53.720 --> 00:02:58.300 called electrolyte, and it's very difficult for electrons to move through electrolyte. 35 00:03:04.860 --> 00:03:08.540 That's awful. If they can't move through the electrolyte, how are they going to 36 00:03:08.540 --> 00:03:09.040 get to those 37 00:03:09.040 --> 00:03:14.180 empty spots on the positive terminal? By traveling through a circuit. When 38 00:03:14.180 --> 00:03:15.240 connected to a circuit, 39 00:03:15.520 --> 00:03:19.400 the electrons can flow through the circuit from the negative to the positive terminal. 40 00:03:26.700 --> 00:03:29.520 They travel through all those parts just to get there? 41 00:03:29.760 --> 00:03:30.420 That's right. 42 00:03:30.560 --> 00:03:32.960 And they make all sorts of things happen along the way. 43 00:03:33.380 --> 00:03:36.600 You mean like lighting up an LED or making a motor move? 44 00:03:36.920 --> 00:03:37.400 Exactly. 45 00:03:37.400 --> 00:03:39.360 And it all starts inside the battery. 46 00:03:45.820 --> 00:03:47.460 Batteries are powerful. 47 00:03:47.820 --> 00:03:49.860 It must be pretty difficult to make them. 48 00:03:50.380 --> 00:03:52.360 Actually, we can make one right here. 49 00:03:52.540 --> 00:03:53.060 It's easy. 50 00:03:53.620 --> 00:03:55.240 Right, I'll go get the chemistry set. 51 00:03:55.380 --> 00:03:56.360 Wait, wait, don't go anywhere. 52 00:03:56.600 --> 00:03:58.680 Everything we need is right on this table. 53 00:03:59.620 --> 00:04:02.980 Oh, uh, a lemon? 54 00:04:05.060 --> 00:04:05.760 That's right. 55 00:04:05.960 --> 00:04:08.800 The juice inside of this lemon makes for a very good electrolyte. 56 00:04:09.080 --> 00:04:13.140 This galvanized nail is coated with zinc, and we can use that as our negative terminal. 57 00:04:14.040 --> 00:04:17.160 And this shiny copper penny will make a good positive terminal. 58 00:04:17.920 --> 00:04:19.940 So, how do we put it all together? 59 00:04:20.160 --> 00:04:20.600 Easy. 60 00:04:20.600 --> 00:04:24.620 First, we roll the lemon while pressing down on it to make sure there's lots of 61 00:04:24.620 --> 00:04:25.520 juice flowing inside. 62 00:04:30.260 --> 00:04:32.720 Then insert the penny on the right side 63 00:04:32.720 --> 00:04:37.140 and a galvanized 64 00:04:37.140 --> 00:04:43.260 nail on the opposite side. So simple, can we test it with the multimeter? That's a 65 00:04:43.260 --> 00:04:43.700 good idea. 66 00:04:50.300 --> 00:04:53.920 Our lemon battery is producing about one volt. 67 00:04:56.220 --> 00:04:58.180 Is that enough to power an LED? 68 00:04:58.560 --> 00:05:03.120 Not quite, but what we can do is link multiple lemon batteries together in series 69 00:05:03.120 --> 00:05:03.820 to increase 70 00:05:03.820 --> 00:05:05.300 the voltage. Excellent. 71 00:05:23.260 --> 00:05:26.400 We now have a total of four lemon batteries. 72 00:05:28.540 --> 00:05:30.460 Now how do we connect them all together? 73 00:05:32.260 --> 00:05:36.720 To connect batteries in series, we connect the positive terminal of one battery to the 74 00:05:36.720 --> 00:05:38.460 negative terminal of the one next to it. 75 00:05:38.460 --> 00:05:40.240 We'll use these alligator clips. 76 00:05:51.480 --> 00:05:55.480 Now the two remaining terminals can connect to our LED. 77 00:05:55.920 --> 00:05:56.520 Correct. 78 00:06:08.920 --> 00:06:11.160 Wow, it really does work. 79 00:06:15.480 --> 00:06:17.560 An LED powered by lemons. 80 00:06:17.900 --> 00:06:19.040 Not just lemons. 81 00:06:19.260 --> 00:06:20.300 Don't forget, Adabot. 82 00:06:20.420 --> 00:06:25.060 It's the lemon, the zinc nail, and the copper penny that work together to create 83 00:06:25.060 --> 00:06:27.720 the electrochemical reaction that generates current. 84 00:06:28.220 --> 00:06:30.620 And they sure do make a lot of juice. 85 00:06:30.880 --> 00:06:32.200 They sure do, Adabot. 86 00:06:32.520 --> 00:06:34.760 We'll never have to buy batteries again. 87 00:06:34.760 --> 00:06:38.660 Well, even though we did make a working battery, they're quite large, and they 88 00:06:38.660 --> 00:06:41.260 wouldn't fit in my multimeter, so for now I think we should continue buying 89 00:06:41.260 --> 00:06:41.720 batteries. 90 00:06:42.220 --> 00:06:45.120 Oh. Can we make lemonade instead? 91 00:06:45.380 --> 00:06:46.160 Sure. Why not? 92 00:07:10.680 --> 00:07:11.780 We'll see you next time.