I opened up the Star Tribune to a sad story. From the Star Tribune:
Thursday morning, ninth-graders in the second-hour science class at Maple Grove Junior High School had turned their desks toward the science table where teacher Matthew Achor conducted experiments for the class final.
The first time the teacher dropped a match into a jug of methanol, Neuberger said the experiment seemed to work. “It made a loud boom and a little flame,” he said. “Everyone thought that was cool and clapped.”
Neuberger looked down at his paper to begin writing down his observations. “I’m pretty sure he was starting it up to do it a second time,” Neuberger said. “And the next thing I know I’m on fire.”
Several students were injured during this science experiment. One of the students, Dane Neuberger, was severely injured with second degree burns to his face. All of the students are expected to make a full recovery, and according to the article it doesn’t look like Neuberger will need skin grafts. Only minor damage was sustained to the classroom.
Details are slim in the article, but it sounds like the appropriate actions were taken after the explosion. A fire blanket was used to wrap Neuberger and an ambulance was called immediately. The room was evacuated and the fire department was called to investigate. The article doesn’t discuss the type of bottle or the amount or type of methyl alcohol employed in the experiment.
The science behind what was being taught.
The purposes of this experiment could be to demonstrate an exothermic reaction, oxygen supply in combustions (if a narrow-necked bottle is used as heat, flame and gas exits the bottle, fresh oxygen is sucked back into the bottle, re-igniting any remaining methanol vapor), detonation velocity, expansion of gases, etc.
This video shows the experiment as performed on four different alcohols:
The way it works is that liquid methanol is put into a bottle and allowed to evaporate, leaving methanol vapor in the bottle. Heat energy – a match, in this case – is added to the bottle, causing a combustible chemical reaction. Visible flame and a loud whoosh” is heard during the reaction. The methanol vapors are ignited, and liquid by-product (H2O) is left in the bottom of the bottle.
In the article above it’s mentioned that this teacher had been performing this experiment for years, and I found several online mentions of this as an acceptable high-school chemistry-level experiment. Some sites perform the study outdoors, some indoors. I do not remember this experiment performed when I was in junior high or high school.
Science teachers – Do you use this experiment in your classes? What safety precautions do you employ? For the rest of you – Do you remember this experiment from your days in the chemistry classroom? Did you have any larger-than-intended explosions?