In this video, a person is seen holding a glass beaker with a tube attached to it. The person is using a marker to draw a line on the tube. The beaker is placed on a table, and the background shows a classroom setting with tables and chairs. The person's hands are visible, and they are wearing a ring on their left hand. The marker appears to be a black permanent marker. The tube is transparent and has a diameter that is slightly larger than the marker's tip. The person draws a straight line on the tube, and the line is visible against the tube's surface. The person's movements are steady and precise, indicating that they are experienced in this task. The video does not contain any audio, and there are no other people or objects in the frame.