Chemistry Lecture Demonstration Facility - Demos

Carbon Dioxide Flame Extinguisher

Brief Description:

Gaseous carbon dioxide is poured into a clear walled vessel containing four lit tea candles suspended at varying heights. The candles are extinguished one at a time from the lowest to the highest.

Purpose/Goal:

Illustrate the concept of carbon dioxide not being able to support combustion, as well as showing that carbon dioxide is denser than air.

Explanation of Experiment:

Solid carbon dioxide (dry ice) sublimes at a temperature of -78.5 °C.  At this temperature, it has a density of 1.56 g/L.  The density of oxygen at 25 °C is 1.31 g/L.  As the more dense carbon dioxide is poured into a vessel containing four lit candles suspended at varying heights, the candles are extinguished one at a time from the bottom up.

Materials Preparation:

Prepare a clear plastic tank by placing four jars and/or beakers of varying capacities inverted so that you have a cascading array. Place a tea candle on the bottom of each beaker/jar. Place a number of pieces of dry ice in a plastic pitcher and allow them to stand for ca. ten minutes in order to allow it to fill with carbon dioxide gas. Have a barbecue lighter ready to ignite the candles.

Presentation:

Light the candles and slowly pour the carbon dioxide gas into the containment vessel. Point out that the heavy gas can be poured much like a liquid, but it cannot be seen. The candles will extinguish one by one from the bottom up.

Hazards:

Handle dry ice with protective gloves. Keep flammables away from open flames. Never place dry ice in a sealed container. Wear appropriate eye protection.

Disposal:

Allow excess dry ice to sublime. All other materials may be reused.

Video:

General Concept:

  • Gases

Type of Reaction:

  • Combustion

Primary Reference:

  • Bilash, B., Gross, G.R. and Koob, J.K. (2010), A Demo A Day - A Year of Chemical Demonstrations, Flinn Scientific Inc., p.25.

Tags:

Contact

Bob Porcja
porcja@chem.rutgers.edu
848-445-5157

Location

Beck Hall Auditorium
99 Avenue E
Piscataway, NJ 08854

The CLD Facility is located in the prep room adjacent to the Beck Hall Auditorium (map).

CLD Facility