B is for Battery

automatic captions, checked for structure and key terms; corrections welcome

[00:00:01.480] [unclear opening audio]
[00:00:43.880] Hey, Adabot.
[00:00:46.120] Have you seen any of my batteries around?
[00:00:48.220] Oh, hi, Ladyada.
[00:00:49.360] I was just thinking about all the energy stored in these batteries, just waiting
[00:00:53.320] to be used.
[00:00:54.400] That's right. Batteries are really cool.
[00:00:56.160] And they're even cooler when they're used to power my multimeter.
[00:01:04.500] Batteries give us electricity on the go without needing to plug into a wall socket.
[00:01:08.920] But there's one thing I don't understand.
[00:01:10.940] What's that, Adabot?
[00:01:12.320] How do we fill batteries up with electricity in the first place?
[00:01:16.500] Well, batteries aren't really filled with electricity.
[00:01:20.100] They're filled with a bunch of components that generate electrical current.
[00:01:24.360] Oh, you mean they have little machines inside?
[00:01:27.780] Hmm, not exactly. I think we should look this one up.
[00:01:31.820] Agreed. Accessing database. Battery.
[00:01:42.120] There are two important parts of every battery, the positive and negative terminal.
[00:01:55.700] And if we opened up a battery, it would look like this.
[00:02:01.480] huh how does that make electricity well a battery uses chemistry to create electricity
[00:02:07.740] is called an electrochemical reaction oh sounds powerful
[00:02:12.700] it definitely is each terminal in a
[00:02:16.600] battery is made of a different kind of material the negative
[00:02:22.420] terminal is made of material that
[00:02:23.920] has a lot of extra electrons in it
[00:02:25.900] it looks
[00:02:31.800] pretty crowded in there it sure
[00:02:33.740] is and all those electrons really want to get some more space they want to go
[00:02:37.540] over to the positive terminal which has a lot of holes so the electrons can fit
[00:02:41.100] into them
[00:02:41.580] it doesn't look
[00:02:47.560] too far can't they just jump to the positive terminal
[00:02:50.400] they can't do that because the battery is filled with a special chemical
[00:02:53.720] called electrolyte, and it's very difficult for electrons to move through electrolyte.
[00:03:04.860] That's awful. If they can't move through the electrolyte, how are they going to
[00:03:08.540] get to those
[00:03:09.040] empty spots on the positive terminal? By traveling through a circuit. When
[00:03:14.180] connected to a circuit,
[00:03:15.520] the electrons can flow through the circuit from the negative to the positive terminal.
[00:03:26.700] They travel through all those parts just to get there?
[00:03:29.760] That's right.
[00:03:30.560] And they make all sorts of things happen along the way.
[00:03:33.380] You mean like lighting up an LED or making a motor move?
[00:03:36.920] Exactly.
[00:03:37.400] And it all starts inside the battery.
[00:03:45.820] Batteries are powerful.
[00:03:47.820] It must be pretty difficult to make them.
[00:03:50.380] Actually, we can make one right here.
[00:03:52.540] It's easy.
[00:03:53.620] Right, I'll go get the chemistry set.
[00:03:55.380] Wait, wait, don't go anywhere.
[00:03:56.600] Everything we need is right on this table.
[00:03:59.620] Oh, uh, a lemon?
[00:04:05.060] That's right.
[00:04:05.960] The juice inside of this lemon makes for a very good electrolyte.
[00:04:09.080] This galvanized nail is coated with zinc, and we can use that as our negative terminal.
[00:04:14.040] And this shiny copper penny will make a good positive terminal.
[00:04:17.920] So, how do we put it all together?
[00:04:20.160] Easy.
[00:04:20.600] First, we roll the lemon while pressing down on it to make sure there's lots of
[00:04:24.620] juice flowing inside.
[00:04:30.260] Then insert the penny on the right side
[00:04:32.720] and a galvanized
[00:04:37.140] nail on the opposite side. So simple, can we test it with the multimeter? That's a
[00:04:43.260] good idea.
[00:04:50.300] Our lemon battery is producing about one volt.
[00:04:56.220] Is that enough to power an LED?
[00:04:58.560] Not quite, but what we can do is link multiple lemon batteries together in series
[00:05:03.120] to increase
[00:05:03.820] the voltage. Excellent.
[00:05:23.260] We now have a total of four lemon batteries.
[00:05:28.540] Now how do we connect them all together?
[00:05:32.260] To connect batteries in series, we connect the positive terminal of one battery to the
[00:05:36.720] negative terminal of the one next to it.
[00:05:38.460] We'll use these alligator clips.
[00:05:51.480] Now the two remaining terminals can connect to our LED.
[00:05:55.920] Correct.
[00:06:08.920] Wow, it really does work.
[00:06:15.480] An LED powered by lemons.
[00:06:17.900] Not just lemons.
[00:06:19.260] Don't forget, Adabot.
[00:06:20.420] It's the lemon, the zinc nail, and the copper penny that work together to create
[00:06:25.060] the electrochemical reaction that generates current.
[00:06:28.220] And they sure do make a lot of juice.
[00:06:30.880] They sure do, Adabot.
[00:06:32.520] We'll never have to buy batteries again.
[00:06:34.760] Well, even though we did make a working battery, they're quite large, and they
[00:06:38.660] wouldn't fit in my multimeter, so for now I think we should continue buying
[00:06:41.260] batteries.
[00:06:42.220] Oh. Can we make lemonade instead?
[00:06:45.380] Sure. Why not?
[00:07:10.680] We'll see you next time.