Safety Alert – Stop Using the Rainbow Demonstration
The American Chemical Society Committee on Chemical Safety recommends that the “Rainbow” demonstration on open benches involving the use of flammable solvents such as methanol be discontinued immediately. When carried out on open benches (outside of a chemical hood) these demonstrations present an unacceptable risk of flash fires and deflagrations that can cause serious injuries to students and teachers.
On an open bench, invisible flammable vapors can flow across and off of the bench to the floor where they can be ignited by a flame, a spark (even static electricity), or even a hot surface. Even carrying out this demonstration in a hood poses risks if solvents are not adequately controlled.
If you are considering this “Rainbow” demonstration or have used it in the past, we urge you to stop using this demonstration. There are alternatives available that demonstrate the same rainbow colors but don’t use flammable solvents on an open bench. These alternate demonstrations involve soaking wooden splints in salt solutions and then placing the splints in a Bunsen burner to observe the salt’s characteristic color.Link to the whole document, with the alternatives at the bottom of the page. So what is the best way to get this in front of high school chemistry teachers?
In the matter of the Beacon School incident, the teacher has been reassigned for now from her position at the school.