Explanation:
Huang He floods, (1887, 1931, 1938), series of devastating floods in China caused by the overflowing of the Huang He (Yellow River), the country’s second longest river. These three floods collectively killed millions and are considered to be the three deadliest floods in history and among the most destructive natural disasters ever recorded.
This represents the source of research ideas called classroom lecture.
There are several sources which can inspire and help someone to develop a research question. Some of them are theory, everyday occurrence, serendipity and past research. In this case, Whitney was taught about the bystander effect in her social psychology course and she was inspired to undertake an undergraduate research project on this subject.