Can Jello Brand Instant Gelatin replace coal fired power plants? Probably not but it can be used to build a demonstration microbial fuel cell from common materials. This is a fun classroom or rainy day project, tie multiple cells together and use the power to light an LED. You'll probably need a joule thief as well. Output voltage and current are a function of cell volume and carbon electrode size.
Here's how it works, we're going to mix a little Jello brand Instant Gelatin with some Fleischmann's Active Yeast and a few drops of plant food. Once that solidifies we're going to cut out some fun Jello squares (yes, they still jiggle) and, using the carbon paper as electrodes, we're going to tap the energy produced by the yeast to create electricity.
This is an innovative form of the popular single cell microbial fuel cell or MFC. The gelatin serves a variety of useful purposes, including MFC container, fuel source and electrolyte. The yeast will feed primarily off of the sugar in the gelatin mix while the gelatin seals out ambient oxygen.
As you can see we started off with about 500 mV which ain't bad for some Jello and yeast...
Now let's get started!
Step 1: Bill of Materials
Not much to this one.
The hardest item to find, believe it or not, was actual old fashioned carbon paper. I ended up ordering over the net since I couldn't find it in my local stores. Make sure you get real carbon paper since that is used for the carbon electrode and will significantly impact the performance of your MFC.
You'll need some instant gelatin. You want the kind with sugar in it (or that you add sugar to). I used Jello brand Instant Gelatin in lime flavor for reasons which will become obvious. Any gelatin should do, including unflavored gelatin with a cup or so of sugar dissolved in it.
You'll need some yeast. I used Fleischmann's Active Dry yeast for no particular reason other than it was there.
A candy thermometer or some other good way, including judgement, to keep from putting the yeast until the water has cooled down to 100 degrees or so.
A container, I used a square glass one that was handy. It should be convenient for cutting squares out of.
If you have some handy a little Instant-Gro or Shultz's plant food adds useful supplements to the medium.
Now that we have everything let's make some Jello...