AP_环境科学_Environmental Science - A Global Concern (10th Edition)-81-120.pdf

absorbed in changing states is also critical. As you will read in chapter 15, evaporation and condensation of water in the atmo- sphere helps distribute heat around the globe. Energy that is diffused, dispersed, and low in temperature is considered low-quality energy because it is difficult to gather and use for productive purposes. The heat stored in the oceans, for instance, is immense but hard to capture and use, so it is low quality. Conversely, energy that is intense, concentrated, and high in temperature is high-quality energy because of its usefulness in carrying out work. The intense flames of a very hot fire or high- voltage electrical energy are examples of high-quality forms that are valuable to humans. Many of our alternative energy sources