We like science inquiry projects that are more hands-on. The ones where students need to build a physical prototype, test it, and refine it. Sure, there are those who like science inquiry projects resulting in a poster or PowerPoint presentation. But, I prefer the physical. And, in an age where students spend a bulk of their time on the computer anyways, I think students appreciate the physical too. The problem is, what prototyping projects lend itself to being a good science inquiry project? Yes students can always build popsicle stick bridges. But, with time constraints, it’s hard to spend time building bridges if they don’t fit in the curriculum. In a previous post (#29), we provide a science inquiry project where students build solar ovens in order to study the behaviour of light, which ties to the parts of the curriculum focusing on light. That’s the type of science inquiry project I enjoy having students do. Projects where students build, test, and apply their prior knowledge to a goal that gets kids out of their desks is what I like. But, again, finding a simple inquiry project that hits all the criteria I set forth is challenging.

So, when I learned how bacteria in mud can be used to create a mud battery, I got real excited. We tested it out and, yes, it’s true. The bacteria in mud can produce a low voltage under the right conditions. And, such a project connects well with multiple parts of the science curriculum too. For example, this project can connects with the electric circuits and voltages curricula as well as the abiotic/biotic conditions necessary for life. And, with a variety of ways to make a mud battery – especially one that produces the most voltage – this project makes for a simple inquiry project that connects well with content and competencies. In this post, we outline how we set up a demo version of a mud battery. We also provide some useful links as well as a handout that is available for download at the end of the post.

Just how simple is our simple inquiry project?

The battery is relatively easy to make and the parts easy to source. All that’s needed is a couple of insulated wires, a container (glass or plastic), some mud, sugar, water, and two squares of felt. You do not need electrodes or wiring of different metals.

We followed the video instructions on setting up a mudwatt kit the first time we set up our battery (see below).

Note: The main difference between mudwatt and our homemade mud battery is that we don’t attach our wires to a circuit or LED. Rather, we measure the voltage produced by connecting the wires to a multimeter. However, if you want all the bells-and-whistles that come with an actual mudwatt, you can buy them by clicking here.

After setting up the battery, wait a day before testing for voltage. Our battery produced 0.60V of electricity a day after our initial setup.

The Potential (literally)

The purpose of this lab is not just to build a battery but to make it better. And, by better, we mean a battery that can produce the most voltage. That is the inquiry question students tackle in this project.

And, there are a number of variables students can modify to achieve this. Students can change the wiring, the amount of mud, the type of mud (ie. Where they go their mud from), the shape and/or size of the container, the nutrient (ex. Sugar) initially being added to the mud, the battery temperature, and the the time between setup and trials. Thus, there are many ways students can approach the goal of making a mud battery that produces the greatest voltage – some of which may not be on the list above yet.

Wrap Up

There are simple inquiry projects and inquiry projects that are just simple. I’m not a big fan of those inquiry projects that have a simple output like having students write a report or produce a PowerPoint presentation. I like simple inquiry projects: those that are easy to set up and require students to build, test, and modify variables in order to get a better result. That’s what we have in the mud battery inquiry project. It’s hands-on, unorthodox, highly demonstrable, and, at the same time, connects well with today’s science curricular standards. And, the materials and setup are simple. I hope you give it a try with your students and let me know how it goes. To download our mud battery inquiry project handouts, click the link below.

Until next time, keep it REAL!

Resources

Handout(s): 31 – Mud Battery Inquiry Project

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