FIGURE 5.7 Energy and entropy. Entropy increases in a system unless an input of energy from outside the system creates order. (a) In order to reduce the entropy of this messy room, a human must expend energy, which comes from food. (b) A tornado has increased the entropy of this forest system in Wisconsin.
(a: Norm Betts/Landov; b: AP Photo/The Post Crescent, Dan Powers)