Poor Man's Barking Dog Chemistry Demonstration

The Barking Dog is a classic chemistry demonstration that illustrates an exothermic decomposition reaction. However, the main point of this demonstration really is to wow students with the wonders of science -- to capture their attention and interest! The reactants are ignited, producing a bright blue flash that travels down the length of a long tube. A characteristic barking or woofing sound accompanies the pyrotechnics. While it's a terrific reaction, it calls for toxic carbon disulfide and expensive glassware. You may choose to skip this demo based on cost or risk. Fortunately, you can perform a demonstration with a similar sound and appearance using household materials. Many places online refer to this as a "bottle fire vortex" or "bottle fire tornado", but there isn't any vortex. It is much more like the Barking Dog reaction. Expect to see a bright blue flame travel down the bottle. You'll hear a bark or woof. It's great fun, plus you can customize the color of the flame (of course)... Try it
Source: About.com Chemistry - Category: Chemistry Source Type: news