"Energy In Context is a core, essential, and vitally important addition to high school, community, college, and university library . . . ”— Bookwatch
“This encyclopedia conveys the basics of energy science in simple and clear text while offering an unbiased explanation of the impact of energy on human life and the environment. — Booklist
Energy is a subject that impacts lives and economies across the globe. Energy: In Context helps students understand the fundamentals of energy science, while also exploring the social, political, economic, and cultural factors that impact how we find, use, store, and sometimes waste energy.
Although the term energy is frequently used in media reports and everyday conversation, energy is actually complex term to introduce to younger students. We describe energy as a tangible substance that can be created, stored, moved about, etc., but energy isn't a tangible physical entity. When we say that the sun's energy powers earth, for example, it isn't energy per se that is transported to earth. Energy itself only exists as a state function (a function of the state or position of matter). In the case of transferring energy from the sun to earth, photons are the vector of energy change.
In a very simplistic manner, we can describe the transfer of energy essentially in terms of light photons, emitted from fusion reactions and excited atoms in the sun, that travel through space at energy levels described by an electromagnetic spectrum of wavelengths and frequencies (or photon energy levels) that then strike something (atmospheric gas, water molecules in the ocean, land, or a sunbather in a park). The impact then changes the energy state of the target atoms so that the net result is that the solar energy obtained from reactions within the sun is effectively transferred to atoms on earth.
Accordingly, instead of a precise definition more commonly used in physics courses, Energy in Context adopts the most common usage for the term energy and thus puts off dealing with conceptual and linguistic complexities until students and readers are more advanced in their studies... (more) -- Brenda Wilmoth Lerner and K. Lee Lerner, editors. Cambridge, MA. June, 2016.