According to this review of learning literature, in large science classes, 92% of the time is spent on lecture, ~4% on student questions and ~4% in silence. During a lecture, students are attentive 56%-60% of the time, based on self-reporting and observation. Student notes record 40% of the lecture material in a 15-min. lecture, 25% in a 30-min. lecture, and 20% in a 40-min. lecture. A class which used a think-pair-share technique for 2-3 minutes for every 12-18 minutes of lecture remembered more of the lecture material directly after the class and twelve days later than the control class that got the same lecture without the TPS breaks.
