Adabot: Woooowwww ...

Ladyada: Hey Adabot - did you see any of my AA batteries arou -- ?

Adabot: Oh hi Ladyada - I was just thinking about all the energy is stored in these batteries … just waiting to be used! … [tilts heads, mesmerized]

Ladyada: Yah … batteries are pretty cool …

Ladyada: … and they’re even better when I use them to power my multimeter

Adabot: Affirmative - batteries allow us to use electricity on-the-go, without needing to plug into a wall socket. Very handy … But there is one thing I don’t quite understand.

Ladyada: Oh? what’s that?

Adabot: Ladyada how *are* batteries filled with electricity in the first place?

Ladyada: Well batteries aren’t exactly filled with electrical energy, they’re filled with a few different things that work together to *create* electrical energy.

Adabot: Wow - you mean like little machines inside that generate electricity?

Ladyada: Umm … sort of … I think we better look this one up.

Adabot: Agreed! Accessing database “batteries”!

Ladyada: Thanks, Adabot. There are 2 important parts of a battery - the positive … & negative terminals. Connecting these 2 points to a circuit allows electrical current to flow from one terminal to the other

Adabot: Current, which we measure in amperes!

Ladyada: Exactly. And if we looked inside of a battery, we’d see something like this …

Adabot: Huh - how does that make electricity?

Ladyada: Well a battery uses *chemistry* to produce electricity - we call it an electro--chemical reaction.

Adabot: Ooh - sounds powerful!

Ladyada: It definitely is. Each terminal is connected to a different kind of material inside the battery. The material connected to the negative terminal has *lots* of extra electrons.

Adabot: looks pretty crowded in there!

Ladyada: Yup - it’s so crowded, that those electrons all want to go somewhere with more space for them to move around in.

Ladyada: Lucky for them, the positive terminal has lots of empty spaces for more electrons to fit into.

Adabot: Oh - so why don’t they jump over to the positive terminal with all those empty spots?

Ladyada: They can’t do that because the battery is filled with a special chemical called an electrolyte.

Ladyada: And electrons have a really hard time trying to move through electrolytes.

Adabot: That sounds awful! -- If they can’t move through the electrolyte, how will they ever get to their new homes over on the positive terminal?

Ladyada: By travelling through a circuit! When we connect a circuit to both terminals of a battery we give electrons a new way to get to those nice open spots over on the positive terminal.

Adabot: And they travel through all those different parts of the circuit to get there?

Ladyada: Yes - and they make lots of things happen along the way.

Adabot: Oh - you mean, like lighting up an LED. or making a motor move!

Ladyada: Exactly - and it all starts inside the battery.

Adabot: I was right - batteries are powerful! They must be very difficult to make.

Ladyada: Actually - we can make our own battery right now. It’s easy.

Adabot: Awesome! I’ll go get my chemistry set!

Ladyada: Wait -you don’t have to - we’ve got everything we need right here.

Adabot: A Lemon?

Ladyada: That’s right - the juice inside of a lemon can be used as an electrolyte. This galvanized nail is coated with zinc and we can use that as our negative terminal. And this shiny copper penny will make a good positive terminal

Adabot: How do we put it all together?

Ladyada: First we roll the lemon while pressing down on it to make sure there’s a lot of juice flowing freely inside.

Ladyada: Then insert the penny and nail. And we’re done.

Adabot: You were right - that *was* easy! Can we test it out with a multimeter?

Ladyada: Yup - good idea

Adabot: Our lemon battery is producing about 1 volt. Cool! Is that enough power to light up an LED?

Ladyada: Hmm - not quite. But we *can* link multiple batteries together to increase the voltage.

Adabot: Excellent.

Adabot: Now we have four lemon batteries.

Adabot: But how do we link them together?

Ladyada: To connect batteries in *series* we connect the positive terminal on one battery to the negative terminal of the one next to it.

Adabot: Now the two terminals that are left unconnected are the ones we connect our LED?

Ladyada: Correct!

Adabot: It works! An LED powered by lemons!

Ladyada: Not just lemons - don’t forget - it’s the lemon, nail and penny that are working together to create electrical current.

Adabot: Right - they make a great team!

Adabot: This great - with all these lemons, we’ll never have to buy batteries again!

Ladyada: Well - I don’t think we could fit a lemon inside my multimeter. We’re still better off using regular batteries.

Adabot: Oh …

Adabot: Can we make lemonade instead?

Ladyada: Umm … sure, why not?

This guide was first published on May 09, 2014. It was last updated on May 09, 2014.

This page (Transcript) was last updated on May 08, 2014.

Text editor powered by tinymce.