Mechanical energy nonconservative forces, like frictional forces, will be present, but often they are of negligible values and the mechanical energy's being constant can therefore be a useful approximation. In elastic collisions, the mechanical energy is conserved but in inelastic collisions, some mechanical energy is converted into heat. The equivalence between lost mechanical energy (dissipation) and an increase in temperature was discovered by James Prescott Joule. Many devices are used to convert mechanical energy to or from other forms of energy, e.g. an electric motor converts electrical energy to mechanical energy, an electric generator converts mechanical energy into electrical energy and a
Feathers: The Evolution of a Natural Miracle Adult Science Book category, presented by the American Association for the Advancement of Science and Subaru. "Feathers" was listed among the top ten best books of 2011 in the Sci-Tech category by the "Library Journal". "Feathers" received the John Burroughs Medal in 2013, which is awarded annually by the John Burroughs Association to "the author of a distinguished book of natural history". Reception to "Feathers" has been positive. Amanda Katz, in a review published by "The New York Times", wrote that because "Feathers" is a work of synthesis, bird enthusiasts will find the book's content already "familiar", but noted that