This online calculator converts from one energy unit to another - from gallons to British thermal units (Btu), kilowatt/hours to megajoules, short tons to metric tons.

This video segment, adapted from Need to Know, discusses how the process of hydraulic fracturing (fracking) is used to extract natural gas and how the process may be polluting water resources with hazardous chemicals, leading to health concerns.

This flow chart shows the sources and activities across the U.S. economy that produce greenhouse gas emissions.

This set of flow charts illustrates energy sources and uses in 136 countries around the world. The data from 2007, but is still useful for comparing energy patterns in different countries. This is the first comprehensive package of worldwide, country-level energy flowcharts that has been produced.

In this activity, students calculate electricity use by state and determine, using Google Earth, how much land would be required to replace all sources of electricity with solar panels.

This activity illustrates the carbon cycle using an age-appropriate hook, and it includes thorough discussion and hands-on experimentation. Students learn about the geological (ancient) carbon cycle; they investigate the role of dinosaurs in the carbon cycle, and the eventual storage of carbon in the form of chalk. Students discover how the carbon cycle has been occurring for millions of years and is necessary for life on Earth. Finally, they may extend their knowledge to the concept of global warming and how engineers are working to understand the carbon cycle and reduce harmful carbon dioxide emissions.

In this activity, students learn about the energy sources used by their local utility provider to generate electricity, and work in small groups to evaluate the sustainability of either a renewable or non-renewable energy source used to generate electricity.

This multi-week project begins with a measurement of baseline consumptive behavior followed by three weeks of working to reduce the use of water, energy, high-impact foods, and other materials. The assignment uses an Excel spreadsheet that calculates direct energy and water use as well as indirect CO2 and water use associated with food consumption. After completing the project, students understand that they do indeed play a role in the big picture. They also learn that making small changes to their lifestyles is not difficult and they can easily reduce their personal impact on the environment.

In this activity, students conduct a life cycle assessment of energy used and produced in ethanol production, and a life cycle assessment of carbon dioxide used and produced in ethanol production.

This is a debate-style learning activity in which student teams learn about energy sources and are then assigned to represent the different energy sources. Working cooperatively, students develop arguments on the pros and cons of their source over the others.