more energy available to an object, the more
likely that object is to be changed, or to
change its surroundings. Our kitchens are
organized around this principle. Stoves and
ovens change the qualities of food by pouring
heat energy into it, while the refrigerator
preserves food by removing heat and thus
slowing down the chemical changes that
constitute spoilage.
Atoms and molecules can absorb or release
energy in several different forms, two of
which are important in the kitchen.
The Nature of Heat: Molecular Movement
One kind of energy is the energy of motion, or
kinetic energy. Atoms and molecules can
move from one place to another; or spin in
place, or vibrate, and all of these changes in
position or orientation require energy. Heat is
a manifestation of a material’s kinetic energy,
and temperature is a measure of that energy: