Have you ever seen a foam cup appear to melt away in acetone? Foam cups, bowls, and containers are made of a lightweight but strong material—expanded polystyrene. How then does acetone reduce this substance to a blob of goo? In this week's video, Reactions teams up with chemistry professor Matt Hartings, PhD, to explain the viral phenomenon. Check it out here: https://youtu.be/FrnDB2_Kt-4.