If an elephant used toothpaste, this is probably what it'd look like! Learn about chemical reactions by watching this heat-producing mixture bubble and overflow for up to half an hour. The experiement comes from the Nat Geo Kids book Try This! Extreme.
WARNING: This experiment uses chemicals that can irritate skin and damage clothes, so make sure to use safety goggles, lab apron, and nitrile gloves. Avoid touching or getting the chemicals on skin or clothing. And don't get too close, as heat and steam can be dangerous.