Materials
- 1 small candle (tea light)
- Vinegar (acetic acid)
- Baking soda
- 1 small cup or jar
- 1 larger container
- Matches or lighter (with supervision)
Procedure
- Place the lit candle inside the large container.
- In the small cup, mix a few spoonfuls of baking soda with vinegar. It will fizz.
- Without pouring the liquid, "pour" the invisible gas (carbon dioxide) from the cup toward the candle by gently tilting the cup.
- Watch as the candle goes out without the liquid touching it.
Choose Your Learning Level
Middle School
The reaction between vinegar and baking soda releases carbon dioxide (CO₂), a gas heavier than air. When poured over the flame, it pushes away the oxygen and puts out the fire.
Questions to Think About
- What gas is made during this reaction?
- Why does the flame go out when the gas is poured?
- What role does oxygen play in a flame?
High
Acetic acid (vinegar) reacts with sodium bicarbonate to produce carbon dioxide, water, and sodium acetate. The dense CO₂ displaces oxygen in the container. Without oxygen to sustain combustion, the candle extinguishes.
Questions to Think About
- Write the balanced chemical equation for this reaction.
- What property of CO₂ allows it to push out oxygen?
- How could you test that the gas is carbon dioxide?