Ключевые слова: academic, aged, blackboard, board, chalkboard, chemical, chemist, chemistry, class, classroom, college, discussing, education, experiment, experimenting, explaining, flask, glass, glassware, learning, lecture, lecturer, lesson, looking, man, mature, old, physical, physicist, physics, research, researcher, school, science, scientific, scientist, student, study, studying, substance, teacher, teaching, test, training, tube, tutor, tutoring, university,