Carbon Dioxide Candle Experiment

Contributed by David Jiang

Introduction

• We’ve all seen fire extinguishers before and its powerful stream of nitrogen which can smother a dangerous fire. However, imagine a fire extinguisher that can take out fires “invisibly”. Here is a fun experiment to design your very own, invisible fire extinguisher.

Materials

• 2 regular-sized cups
• Matches/Lighter
• 1 candle
• Vinegar
• Baking Soda

Procedure

1. Put in a couple tablespoons of baking soda in a cup
2. Pour a little bit of vinegar into the same cup and wait for the reaction to settle down
3. Put a candle in another cup
4. Use a match/lighter to light up a candle
5. Use the cup and tilt it over the cup with the candle 
   1. Make sure to not pour the liquid onto the candle

Physics Concepts and Questions

• Fire requires oxygen to burn
• The baking soda and vinegar makes a chemical reaction that makes carbon dioxide gas
• When you pour the carbon dioxide gas over the candle, it pushes the oxygen out of the the cup
  • This is because carbon dioxide is heavier than oxygen, so CO2 sinks, and O2 rises
• There is no oxygen to fuel the candle anymore, so the fire goes out

Conclusions and Further Investigations

• Now that we have tested this experiment, it is time to look for other interesting ways to manipulate our extinguisher:
  • Does the type of vinegar affect the performance of the extinguisher?
    • Compare the time it takes for one type vs another
  • What happens if you try to extinguish the candle when it’s not inside a cup?
    • Does this make it harder/easier to extinguish? Or will it extinguish at all?

Citations

• https://www.stevespanglerscience.com/lab/experiments/co2-extinguisher/