题目

      I’m usually fairly skeptical about any research that concludes that people are either happier or unhappier or more or less certain of themselves than they were 50 years ago. While any of these statements might be true, they are practically impossible to prove scientifically. Still, I was struck by a report which concluded that today’s children are significantly more anxious than children in the 1950s. In fact, the analysis showed normal children aged 9 to 17 exhibit a higher level of anxiety today than children who were treated for mental illness 50 years ago.       Why ar为了比较水和煤油比热容，俊羽同学用两个相同的装置做了如图所示的实验．     物质 水 煤油 体积/ml 100 125 初始温度/℃ 27 27 加热时间/min 6 6 最后温度/℃ 45 63（1）实验过程中俊羽同学测出煤油的最后温度如图乙所示，为 ℃；但此数据比实际测量值  （选填“高”或“低”），其原因是 ．（2）更正错误后，测量数据记录表格中．水和煤油的质量  （选填“相同”或“不相同”），加热结束时，煤油的温度变化比水的温度变化  （选填“高”或“低”），由此表明，  （选填“水”或“煤油”）的比热容较大．（煤油：0.8×103kg/m3）（3）在此实验中，如果要使水和煤油的最后温度相同，就要给水加热更长的时间，此时，水吸收的热量  （选填“大于”或“小于”或“等于”）煤油吸收的热量．（4）从俊羽同学的实验设计上看，用到的主要实验方法是 法，学习物理知识过程中，还用这种方法研究过的力学规律有：  （举一例）．