Will we ever find a suitable, sustainable, and reliable substitute for fossil fuels? Sure, there’s wind, water, or solar power, but these sources are dependent on the conditions of nature and are not always reliable. ScienceDaily reported, on November 3, 2007, that two microbiologists, Rhonda Zeltwanger and Michael Cotta at Washington University in St. Louis, Missouri, may be onto a more reliable source of energy than any of the existing ones mentioned above.

Energy is needed to do work, and work is defined in terms of the size of the force applied to an object times the distance over which the object moves due to the force. For example, car engines have the ability to move automobiles great distances, accomplishing much work, but that also requires a great deal of energy. The energy is harnessed from the oxidation of fossil fuels, also known as organic hydrocarbons. In oxidation reactions, the compound being oxidized loses electrons to other compounds which become reduced. This transfer of electrons accomplishes energy transfer from one source to another, in keeping with the first law of thermodynamics: Energy is neither created nor destroyed.

The work of Zeltwanger and Cotta is summed up in the article this way:

Using the collection’s database information [on 87,000 microbes], the team is searching for microbes that “eat” biomass sugars (e.g., glucose and xylose from corn stover) and are electrochemically active. That means they can transfer electrons from fuel cell sugars without help from costly chemicals called mediators. The electrons, after traveling a circuit, combine with protons in a cathode chamber, forming hydrogen, which can be burned or converted into electricity.

The article ends by pointing out two advantages of this energy source. The first advantage is how cleanly hydrogen burns; no carbon monoxide or carbon dioxide, both greenhouse gases, is produced. The second advantage is no reliance on limited supplies of fossil fuels as a hydrogen source.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

The WU scientists’ work is directly related to the National Science Education Standards of Science as Inquiry, Physical Science and Earth and Space Science. When people brainstorm to solve the ever-present issue of limited energy supplies in the face of seemingly unlimited demands, they apply the methods of science. Using knowledge of the laws of thermodynamics and of oxidation-reduction reactions, scientists can propose reasonable, testable hypotheses to solve the reliance-on-fossil-fuel problem. Turning to hydrogen, rather than hydrocarbons, may contribute to arresting the buildup of greenhouse gases in the atmosphere.

Many middle school students know that CO and CO₂ are greenhouse gases, but they may not know what that means, where these gases come from, or what the implications of greenhouse gas buildup are. Help students to discover both the sources of these gases as well as how their accumulation in the atmosphere impacts abiotic conditions on this planet, which in turn impacts the biosphere. Resources provided in the next paragraph can help you with this. Then lead students in problem-solving/brainstorming activities designed to reduce greenhouse gas emissions. Finally, share with students the content of this article where they can see some of their proposed solutions are being pursued, confirming for them their capacity to “do” science.

Here are some additional resources that are part of the NSDL Middle School Portal collection to facilitate your instruction regarding energy sources and greenhouse gases: Global Warming and Energy: Overview, Quick Take on Energy Sources, and The Carbon Cycle: What Goes Around Comes Around.

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