It is the teacher's responsibility to ensure safe use of flammable and combustible materials.
When such materials are improperly used in demonstrations, such as the “Rainbow Demonstration”, serious injuries to students and teachers may occur.
Teachers should NEVER open a bottle of flammable liquid in the presence of a flame or hot surface (which is a source of ignition). Vapors from flammable liquids are flammable, so when one opens a bottle and tilts it to pour out the liquid, the first thing that leaves the bottle is an invisible, highly flammable cloud of vapor, which will ignite immediately upon contact with a flame or source of ignition (a hot surface or a spark). This is why this demonstration should not be conducted on an open desk or bench.
For example, numerous incidents have been reported recently involving the Rainbow Demonstration where both students and teachers have been seriously injured. This demonstration illustrates metal flame colors using methyl alcohol or ethyl alcohol. Both of these alcohols are extremely flammable liquids and vapors. Use of this demonstration is discouraged; however, it may be performed safely ONLY by trained and experienced demonstrators.