Slow Motion Science: The Horizontal Barking Dog

The barking dog reaction is a fun demo to experience in person—it looks cool, but more importantly, it sounds cool, like a lightsaber combined with a speeder bike. The reaction occurs when you mix carbon disulfide and nitrous oxide, then ignite them.

In this video, Sir Martyn Poliakoff says, "When we recorded it in slow motion, we realized that we didn't understand the reaction as well as we thought we did. So now, we've decided to explore it a bit further." Senior technician Neil Barnes proceeds to set up the "barking dog" horizontally (unlike the typical standing tube demo), then on go the slow-motion cameras. Poliakoff narrates the reaction—we see oscillating fire shooting out of one end, while the other end of the reaction approaches the end of the tube and oscillates.

If you've never heard the barking dog of chemistry, prepare to hear it "woof."