Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Alcohol, Water and Cloth Burning
Name: Pammy S.
Status: student
Age: 11
Location: N/A
Country: N/A
Date: 7/15/2004


Question:
Why is it that when you try to burn a cloth that was immersed in a mixture of alcohol and water, the cloth does not burn? What kind of chemical reaction takes place here?


Replies:
This not an experiment I would recommend because IT COULD CATCH FIRE. For combustion to occur three factors must co-exist: Fuel (here alcohol and cloth), oxygen (from the air), and ignition source(to get the fuel hot enough to produce a self-sustaining flame). In a mixture of alcohol and water, IF THERE IS ENOUGH WATER PRESENT there will not be a sufficient ignition source. HOWEVER, THE ALCOHOL VAPOR ABOVE THE CLOTH could contain sufficient alcohol vapor to ignite, and THAT IS THE UNEXPECTED DANGER.

Alcohol vapor can "flash" that is burn very rapidly -- not quite an explosion -- but a "WOOOSH" that can expand several feet in a fraction of a second. You could get seriously burned by this flash. I do not want to discourage your scientific interest, but this is really a very risky experiment to be trying.

Vince Calder


Pammy,

This is a marginally dangerous experiment inasmuch as its safety depends on a careful balance between the water and alcohol content. Done properly, it works because water has a great heat capacity -- that is, it can absorb a lot of heat without changing much in temperature. When the alcohol/water soaked cloth is ignited, the heat of alcohol's burning is partially absorbed by the warming and vaporization of the water. This keeps the overall temperature to a bearable level during which time the cloth will not burn and can be (sometimes) carefully handled while aflame. In general, I think the experiment is to risky to be worthwhile. A mistake can lead to serious burns or a fire. My advice: Don't do it.

Regards,
ProfHoff 876



Click here to return to the Chemistry Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory