The prize-winning chem study video series is an extremely effective and intriguing addition to any chemistry course. Originally filmed in the 1960s these videos are still popular classics. They feature animation and time-lapse photography, abstract chemical processes and models brought to life, chemical symbols overlaid on the screen. Results of experiments too difficult to duplicate in the classroom.What is chemical equilibrium? How does the chemist recognize it? How is it explained? These three questions are explored and answered as the dynamic nature of equilibrium is discussed. Radioactive iodine tracers in a closed system are used to show the dynamic molecular behavior of the substances when at equilibrium. Duration: 19 minutes.