Wearing a mask is a cheap and easy way to help stop the spread of airborne infections like COVID-19. Here's some slow-motion Schlieren imaging experiments to demonstrate why masks work. Part of the "It's Okay to Be Smart" series. Please note this title contains mature themes and references.
Parts of this video are definitely geared towards older students, but I showed the beginning to a 4th grader and she was astounded by the Schlieren Imaging. It gave her a much better understanding of why masks are important (especially keeping it over your nose).
Extremely informative. Wonderful visualization!