Energy. We know it when we see its effects but have a hard time explaining it. If you ask students to picture the concept of energy, they might conjure up the images in this collection. They might have difficulty explaining how the photographs represent energy, however. Students can understand that images of food, gasoline, and sunlight represent energy, but they might not know how humans have, for millennia, engineered ways to store energy and use energy transformation to do work.
Some of the photographs in this collection illustrate the impact of energy as movement, light, or heat; others show mechanisms engineered to capture, store, and distribute energy. Ask students to consider the costs and benefits of different energy-capturing systems. In addition to the physical science concept of energy, science, and engineering topics directly and indirectly related to the photographs, include natural resources, human impact on earth, and defining and delimiting engineering problems.
Note: In talking about energy, it is easy to use language that suggests that energy is created or destroyed. Strictly speaking, however, energy is conserved in our universe, according to the first law of thermodynamics. Terms such as “generated” or “lost” are common in conversations about energy. When teaching about energy, however, use terms such as convert, flow, distribute, store, release, transfer, transform, input, and outflow. “Heat energy” is a common conversational term. To be accurate, however, “heat” should be used to describe the transfer of thermal energy.