Who was Lorenzo Romano Amedeo Carlo Avogadro? He was the guy who suggested that equal volumes of gases at the same temperature and pressure should contain equal numbers of molecules. This eventually led to a new quantity for the number of particles, that is 602 sextillion! In this four-minute film, young chemists learn exactly what this means. After the video, they can answer a few questions as a review, and link to other resources about Avogadro's number and general chemistry.