Make Your Own Fire Extinguisher
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Materials:
- Candle
- Metal juice lid
- Large bowl
- Matches
- Baking soda
- Vinegar
- Adult Supervision
1. Light the candle. Drip some melted wax onto the center of the juice can lid.
Blow out the candle. While the wax is still soft, push the base of the candle into it,
so that the candle stands up at the center of the metal lid.
2. Place the lid and candle into the large bowl, then cover the bottom of the bowl
with the with one teaspoon of baking soda.
3. Carefully relight the candle.
4. Slowly pour the vinegar down the inside wall of the bowl, being careful not to
pour the vinegar on the wick of the candle.
5. What happened when you added vinegar to the baking soda?
6. If the candle goes out, try to relight it. Can you? If not, why?
7. You can try this a different way. Take the candle out of the beaker and light it.
Then try pouring out the carbon dioxide gas (but not the vinegar and baking soda!)
produced in the beaker over the candle flame.
8. Did the flame go out? If not, rinse out the beaker and try mixing a fresh batch of
ingredients.
How Does It Work:
Carbon dioxide has a density greater than air. As a result, it flows to the bottom of
the beaker filled with air by pushing the air up and out of the beaker. The property
makes it easy to fill containers with carbon dioxide and to pour carbon dioxide
from the beaker over the candle flame.
Carbon dioxide does not support combustion. When the air in the region of the
flame is replaced by carbon dioxide, the candle is extinguished. Carbon dioxide is
used in some types of fire extinguishers. It displaces the oxygen needed for
combustion.
Special Thanks to Steve Spangler Science for providing this experiment.
