On 24-11, a scientific lecture was held as part of the Physical Chemistry course for students of the Petroleum and Energy Engineering Technology Department. The lecture was delivered by Eng. Mohammed Rafee Khudair, who provided a practical demonstration of the Saybolt viscosity tester, explaining its operation and applications in petroleum-related analyses. The session included an overview of the fundamental principles of measuring the viscosity of petroleum derivatives, along with a step-by-step explanation of the laboratory procedure. The aim was to strengthen students’ practical skills and connect theoretical concepts with real engineering applications.