This episode was brought to you by SquareSpace.
Hi everyone and welcome to the very first episode of Pocket science, which is a new
series in which I do science experiments with things that fit in your pocket - and today
we're doing a potato battery.
I know it might sound like the most overdone science experiment, but it was inspired by
an excellent question that I heard at the end of one of Charlie McDonnell's talks, who
was like, pretty cool - so this kid put their hand up at the end and they asked him whether
potato batteries were a real thing and if so, which potato was the best battery.
No one had the answer but I know I wasn't alone in wondering which potato indeed would
be the best one - so this episode is to find that out!
[Intro by Caro Waro & Cristina de Manuel]
Right, so to make a potato battery, first of all, you're quite obviously going to need
a few potatoes.
I very quickly discovered that trying every single type of potato sold in British supermarkets
would A) be time-consuming, a slight waste of food and probably quite boring - so I've
stuck to two types - Jersey Royals and Tesco's Finest Red Potatoes.
There is no particular decision for this choice other than they were my favourite.
That being said, I've found a paper that claimed that boiled potatoes do better at being batteries
than raw potatoes, so I will be testing that as well.
Next up you're going to need material to turn the potatoes into batteries by creating an
anode and a cathode for which we have galvanised wire and copper - although you can use different
materials as well, but this is what I found at my local hardware store.
Next up you're going to want something to actually power your potatoes with, be that
an LED light, a buzzer, maybe a clock, but I actually want to quantify how well the potatoes
do, so instead I've got a voltmeter, or in this case, a multimeter, to test the voltage
of the potatoes.
Right, so we've got all our ingredients to make the potatoes so what we're going to do
now is build the battery and measure the voltage and the amperage, then we're going to boil
the potatoes and measure their voltage and the amperage again and see if there are any
significant differences!
So let's start simple with a Jersey Royal potato... first of all, we're going to need
to put in something made of copper, this is a pipe clip but it's going to work just as
fine, so pop that in...
Then same with the galvanised wire, shove that in as well.
And unbelievably, the battery is ready!! (victory noise) and we're going to test it with a voltmeter
and then we're going to boil it and compare the results.
Ok, so we now have our voltmeter... we're going to set it up, it's pretty straightforward.
Red goes in here *plugs in*, black goes in here *plugs in* and when I touch two things
with these pins it's going to measure the difference in potential, which is the voltage,
so for instance *puts pins on tongue* I'm super-charged!!
It's probably more sensible to actually test it with something such as a battery, which
has a known voltage and I can check that it's working just fine.
So now we're going to do this with our very special potato battery...
So the red goes on the copper (on the +/cathode), the black goes on the galvanised wire.
*eh* 0.16A And then we want to measure the voltage...
[spins from amperage to voltage].
It's going up.
I took the voltage and amperage for two jersey potatoes and began to suspect that the length
of the galvanised wire that was stuck in the potato might actually affect several of those
variables.
Oh dear...
I decided to measure a single red potato but I chose two distant points along the potato
to see if the distance between the wires would have an effect without using two potatoes.
I did notice that the further apart they were, the higher the resistance in the potato - so
let's see what happens when we boil these babies!
Whilst my potatoes are boiling I'm expecting that to be breaking down some of the compounds
inside the potato, meaning that the resistance between the anode and the cathode should go
down, so hopefully that means that the amperage should go up, because there'll be less resistance,
we can draw more power from the potatoes.
We will see by how much though...
Here are our beautiful, freshly boiled potatoes.
Hopefully the temperature won't affect them too much, they definitely feel very squishy.
So let's start with a small potato which will have cooled down a bit more, and for the moment
of truth...
Let's see if the amperage changes...
Ooh!
It does!
That's amazing!
That's loads more than it was before!
At this point, I decided to verify that indeed, the amount of wire in the potato had a significant
effect on amperage.
Woooooow!
The voltage on the other hand remained mostly unchanged after boiling, but here is a full
summary.
Cool!
So what have we learnt from this episode of Pocket science?
Well, I don't know about you but I've certainly learnt quite a lot about potato batteries
- for starters, it does seem that yes, boiling potatoes has a very striking effect on the
amperage, the amount of current you can draw from the potato - which makes sense because
as you're boiling the potato it's actually breaking down the compounds inside, so you'd
expect it to be easier for the electrolyte to transfer across.
The other thing is that the surface area of the anode and the cathode within the potato
(electrolyte) also affects both voltage and amperage which is to be expected and I feel
I probably should have controlled for that.
I feel it's easier with this pipe clip because of its shape, not so much for the wire, I
did not make any markings on it and it just kind of goes straight through the cooked potato.
However, to answer the key question, which potato is the best potato *drum roll please*
- well, out of this grand selection of two I have got to say Jersey Royal potatoes have
won by quite a way.
For starters, they are actually battery sized and they outperformed the red potatoes on
both voltage and amperage - so much for Tesco finest!
Although who knows, maybe the red potatoes could have benefitted from more cooking time.
That being said, feel free to test any other potato types to see if they fare better than
these.
I really hope you enjoy today's episode of Draw Curiosity - I learnt a lot from this,
and before you wander off I've got three bits of news:
Number one: Special message from the potatoes...
Red: Hey Jersey, whatcha up to?
You seem zoned out Jersey: No I'm not!
I'm squaaaare-spaced out Red: What does that mean?
Jersey: It means I'm building my own website so that other tubers can hire me and it's
so simple that even a potato like me can use it!
Red: That sounds really good actually, what should I do if I want a website like that too?
Jersey: Well!
I got mine for 10% off by going to squarespace.com/drawcuriosity and using the code 'DC' at check out
Red: Great!
Keep your eyes peeled for me because I'm coming!
Number two - it's not just me who's been playing with potatoes today, there've been
a lot of edutubers who've been working on their own potato batteries and looking at
other things about potatoes that you probably didn't even know you wanted to know - so go
check that out in the playlist linked above and finally, this is really random but right
now when you're watching this, I'm going to be in South Africa filming a science game
show for Discovery (!!!!). I'm appearing on one episode, still don't quite know what it's
going to be all about and I'm probably not going to be allowed to speak about it once
it's happened but I'm really excited for the trip and I'm going to start packing as soon
as I finish this.
So, I just wanted to let you know - and with all that being said, thank you so much for
watching me and I'll see you in the next one! Bye!
[MUSIC: Thastor & CryoSleepKitten] [Art & Animation: Cristina de Manuel & Caro
Waro] [Hosting, editing, scripting: Inés Dawson]
[Translated by {your name} into {language}]