Do you want to get your hands really dirty and do some real science?
Then turn mud into electricity in this science project with the help of a microbial fuel
cell!
To get mud for your microbial fuel cell, you can collect some topsoil from the forest,
or go the nearest pond and dig up some mud from the bottom of the lake, or simply grab
some soil from your backyard.
Once you collected your mud, you are ready to set up your microbial fuel cell.
For this you will need from your kit, one microbial fuel cell vessel, that comes with
a lid, one anode with a green wire, one cathode that has an orange wire, one pair of nitrile
gloves and one green hacker board, one red LED and one blue capacitor.
The next step is to prepare your soil.
First, grab the soil that you collected, and get a glass of water, which should be distilled
water and then – don’t forget to wear your gloves.
Pour the water into the soil to make a moist mixture.
Mix it with your hands until you have a cookie dough-like consistency.
It shouldn’t be too wet but also not too dry.
Now you are ready to prepare your electrodes.
Make sure you wear your gloves and start with the anode – the one with the green wire.
Take it out of the bag and take the wire.
Where the insulated part and the bare part of the wire meet, make a 90 degree angle.
Straighten the metal part with two fingers and insert the wire into the graphite disc
making sure it doesn’t come out at the top or the bottom.
Repeat the same steps with the cathode, the one with the orange wire.
Let’s put all pieces together now to assemble the microbial fuel cell.
Have your mud and the electrodes ready.
Take your microbial fuel cell vessel and put some of the mud into the bottom, pat it down
and flatten the surface until it reaches the 1 cm mark on the vessel.
Then take the prepared anode with the green wire and put it on top of the mud.
Grab more mud and put it on top of the anode.
Make sure to press the mud down firmly onto the anode so you don’t trap any gas bubbles
underneath.
Put more mud in and flatten the surface until you reach the 5 cm mark on your vessel.
Then it is time to get your cathode with the orange wire and put it on top of the mud.
You want to place the orange wire slightly to the side of the green anode wire.
Press it lightly on top but make sure there is no mud on top of the cathode.
Let the microbial fuel cell sit for 5 minutes and once the mud has set, take the vessel,
press slightly on the cathode and pour any excess liquid into a cup.
Before you close the microbial fuel cell, take a paper towel and clean any dirt from
the rim of the vessel.
Then take the lid and the green hacker board and insert it into the indented area.
Then take the orange wire that comes from the cathode and insert it into the hole that
is closer to the plus sign.
Next, take the green wire that comes from the anode and insert it into the hole that
is next to the minus sign.
Press the lid firmly on top of the vessel until it snaps into place.
Once you closed the lid, take the orange wire that comes from the cathode, bend it and insert
it into the pin on the hacker board that is next to the plus sign.
Then take the green wire that comes from the anode, bend it and insert it into the pin
next to the minus sign.
Now we will set up the blinker mode for the microbial fuel cell.
For this you will need the red LED and the blue capacitor.
Notice, that the capacitor has two leads, one long and one short.
Take the long lead and bend it a little bit, then insert the long leg into pin 1 and the
short leg into pin 2 of the hacker board.
Next, take the red LED that also has a long lead and a short lead.
Again, bend the long lead a little bit and insert the long leg of the LED into pin 5
and the short leg into pin 6 of the hacker board.
Pins 3 and 4 remain empty.
Now, your microbial fuel cell is ready to blink!
To see written directions for this and thousands of other science and engineering project ideas,
visit us online at www.sciencebuddies.org.