1Hi Doug.
2Hi Wayland.
3I have a question for you.
4How do batteries work?
5That's a great question.
6Well, believe it or not, the answer to this question involves a story about frog legs.
7Yeah, you heard me right, frog legs.
8Now, some people prepare and eat the legs of frogs,
9just like some people eat chicken legs.
10But one scientist by the last name of Galvani
11had a dead frog in his laboratory one day.
12Not because he was going to eat it,
13but because he was getting ready to study it.
14Galvani was really interested in figuring out how people's bodies work.
15Things like muscles and organs.
16At that time, this was a few hundred years ago,
17nobody knew yet how exactly people or animals move their muscles.
18It's hard to see how muscles work from the outside of an animal's body,
19so it can help to look inside.
20If an animal dies, scientists can do an operation like a doctor.
21This is what's called a dissection.
22So Galvani had prepared the frog's legs
23so that he could dissect them and study the muscles.
24Because he didn't want the frog's legs to rot,
25he had soaked them in some salt water overnight.
26He got one out, put it in his dissection pan, and then,
27as he started to cut it with his scalpel,
28something amazing happened.
29The leg suddenly began to twitch and jump.
30Now obviously, this was extremely surprising.
31The frog, after all, was dead.
32Its legs shouldn't have been able to move.
33Galvani got so excited.
34He felt that he had discovered some kind of special power within the frog's muscles.
35He thought he must be so close to unlocking the secret of how animals move their muscles.
36Well, news of Galvani's discovery spread fast among all the scientists living at that time.
37Lots of them were excited to see if they could unlock the secret of how animals move.
38One of those scientists, a scientist by the last name of Volta,
39found something even more surprising than Galvani.
40As Volta tried to repeat Galvani's experiments,
41he became convinced that the twitching of the frog's leg
42actually had almost nothing to do with the frog
43and everything to do with the metal tools that Galvani was using.
44For example, Volta found out that in one of Galvani's experiments,
45the frog's leg would only twitch when it was being touched by two different metals.
46You see, Galvani had used a tool containing the metal copper to hold the frog's leg in place,
47and Galvani's knife was made of a different kind of metal,
48a metal containing iron.
49Volta wondered:
50what if this special power that Galvani discovered was actually something contained not in frog's muscles,
51but in the two different metals?
52Using no frog legs at all, Volta took two pieces of metal,
53one of copper and one of iron,
54just like the metals used in Galvani's experiment.
55Then he connected a piece of wire to each metal disk.
56When he touched the two wires together,
57well, at first nothing happened.
58But that's when Volta remembered
59there was one other substance involved in Galvani's frog leg experiments:
60salt water.
61Volta added a little disk of cardboard soaked in salt water
62between the pieces of metal.
63Suddenly, now when he connected these together,
64he could feel a slight shock.
65By stacking up little sandwiches of each metal
66separated by disks of salt water-soaked cardboard,
67Volta discovered that he could increase the strength of the shock.
68With enough of these little disks all piled up,
69he could even create a spark.
70It looked just like he was making a little lightning bolt.
71What Volta had just invented was the very first battery.
72In fact, to this day, in some languages, like in French,
73a battery still goes by the name of Volta's pile.
74At the time that the battery was invented,
75Volta and others didn't actually know what kinds of things they'd be useful for.
76No one had invented anything powered by electricity yet.
77But over time, as you can guess, that all changed.
78Today, batteries are one of the most useful inventions ever.
79Since batteries are a portable form of electricity,
80they allow us to power things without having to be anywhere near an electrical outlet.
81Without batteries, we'd have no ability to use smartphones, electric cars,
82not even flashlights.
83Today's batteries may look different from the first battery ever invented,
84although some look incredibly similar on the inside.
85Either way, all batteries still work the same basic way.
86They all use Volta's amazing discovery
87that when you sandwich together two different metals between some kind of liquidy solution,
88like salt water or acid,
89electricity is produced.
90That's all for this week's question.
91Thanks, Waylon, for asking it.