سؤال قراءة ستيب محلول — الفكرة الرئيسية (تدريب 5893)

(1) Heat is the exchange of thermal energy between a system and its surroundings caused by a temperature difference. There is a distinction between temperature and heat. Temperature is the measure of the thermal energy of a sample of matter. Heat is the transfer of thermal energy. (2) Thermal energy always flows from matter at higher temperatures to matter at lower temperatures. For example, a hot cup of coffee transfers thermal energy- as heat--to the lower temperature surroundings as it cools down. Imagine a world where the cooler surroundings actually got colder as they transferred thermal energy to the hot coffee, which got hotter. Such a world exists only in our imaginations, because a transfer of heat from a hotter object to a colder one is a fundamental principle in our universe--no exception has ever been observed. Consequently, the thermal energy in the molecules within the hot coffee distributes itself to the molecules in the surroundings. The heat transfer from the coffee to the surroundings stops when the two reach the same temperature, a condition called thermal equilibrium. At thermal equilibrium, there is no additional net transfer of heat. What is one important idea about heat transfer that the writer mentions in