Smoke and mirrors: Dave Arnold plays around with liquid nitrogen in a cocktail glass during his interview with NPR's Ari Shapiro. Claire Eggers/NPR hide caption

itoggle caption Claire Eggers/NPR

The Smitten Ice Cream shop in the Hayes Valley of San Francisco serves fresh ice cream with one novel ingredient: liquid nitrogen. The shop is located inside of a repurposed shipping container. Alan Greenblatt/NPR hide caption

itoggle caption Alan Greenblatt/NPR