The second is the interval after receiving a response and before saying anything. For the first interval, the average teacher waits 0.9 seconds. The wait for the second interval is usually much shorter. Speculative thinking increases. Students ask more questions.
Students propose more investigations.
Student achievement improves. Classroom discipline improves. Teachers ask fewer questions. Teachers ask better questions, requiring higher-order thinking skills. The first wait-time interval is important to allow a student to consider a question and formulate a response.