This 33-second student think-aloud shows a high school student reading the introduction to an excerpt from a 1925 biology textbook. During the video, she expresses excitement about the opportunity to find an answer to a question she asked about how biology had been taught in the 1920s. She also expresses enthusiasm about having access to a primary source—"the actual one," as she calls it. This video shows how using primary sources can engage and intrigue students, and is accompanied by a written commentary. Find the document the student reads here.