Two translucent liquids are mixed. At first, nothing happens: the resulting solution is still translucent. Suddenly, with no warning, the solution turns blue-black all at once.

Curriculum links include redox reactions, rate of reaction, kinetics

In this predict-observe-explain activity, students explore different ways of extinguishing a flame with some surprising results. The lesson is introduced with the video of engineer Yusuf Muhammad. Yusuf is developing a revolutionary new household fire-safety device, incorporating the techniques of professional...