“热”并不是一个专用的物理名词,在教材中没有给它下一个确定的定义,但在初中课本中却直接使用了:“热”字。例如:“热膨胀”、“热传递”、“热现象。、”热机“、”消耗热做功“、”摩擦生热“等等。以上几句话中虽然都包含有”热“字,但在不同的场合”热“字的含义是不同的。有时表示温度,有时表示热量,有时表示热能。 ”Hot“ is not a special physical noun. In the textbook, it does not give it a definite definition. But in junior high school textbooks, the word ”Hot“ is used directly. For example: ”thermal expansion “, ”heat transfer“, ”thermal phenomenon “, ”heat machine“, ”consumed heat work“, ”friction heat", etc.. Although the words “Hot” are included, the meaning of the word “Hot” is different on different occasions. Sometimes it means temperature, sometimes it means heat, and sometimes it means heat energy.