Historic time capsule found at Washington Monument. Before you go, we thought you'd like these... BALTIMORE (WBAL) -A piece of history has been discovered in Baltimore. The original cornerstone of the Washington Monument in Baltimore, thought to be long lost, was discovered last week while crews dug for a sewage tank.
We divide our energy use among four economic sectors: residential, commercial, transportation, and industrial. Heating and cooling our homes, lighting office buildings, driving cars and moving freight, and manufacturing the products we rely on in our daily lives are all functions that require energy.
Sources of Energy. We use many different energy sources to do work. Energy sources are classified as renewable or nonrenewable. Renewable and nonrenewable energy can be converted into secondary energy sources such as electricity and hydrogen. In the United States, most of our energy comes from nonrenewable energy sources.