Whoosh Bottle #2 0708

Saturday 19 February 2011

Whoosh Bottle #2 0708

!±8± Whoosh Bottle #2 0708

I do a set of demonstrations showing factors that affect the rates of chemical reactions. This one here shows the affect of surface area. It starts out pretty boring as I light alcohol in an evaporating dish [which was not independently filmed]. I then pour the same amount of alcohol out on the table and it is clearly seen that the alcohol on the table burns faster because of its large surface area. The fire stops when it runs out of alcohol, but it can be seen that the fire in the evaporating dish is still going. This serves as a segway into the another factor affecting reactions: amount of reactant. To show that it is possible to run out of the oxygen rather than the alcohol, I add the same amount of alcohol to a bottle and shake it up to mix it with the oxygen and to helpit vaporize. I then pour out the excess and light the bottle. After the burn I pour out some more excess alcohol and light it on the table, verifying that I ran out of oxygen rather than alcohol this time. I work my way up in bottle size to add to the drama and because once a bottle has been used it cannot be reused immediately because it full of CO2 (waste gas). This is the first bottle that I use, a small one that is about 500 mL (1/2 liter) big. This demonstration was preformed on a fire proof table surface with an alcohol [which burns relativly cool] under controlled lab conditions with the audience a safe distance away and the instructor taking all safety precautions. The teacher that taught me ...