Carbon dioxide (CO2) is a gas that is heavier than air. When we breath in we’re inhaling oxygen and when we breath out we’re exhaling carbon dioxide. In this sense, carbon dioxide is a waste product as it can kill us if too much builds up in our system. Fire also needs oxygen in order to burn. Because of this, carbon dioxide is often used in fire extinguishers.
Breathing out is not the only way to produce carbon dioxide. By mixing baking soda with vinegar, you not only cause an interesting fizzing reaction, you’re also producing carbon dioxide. This experiment shows what happens when fire is introduced to carbon dioxide.
What you need:
Before you actually get the experiment started, take a paper and pencil add make a chart like the following one.
| Questions | Experiment 1 | Experiment 2 | Experiment 3 |
|---|---|---|---|
| How much baking soda was added? | ___ | ___ | ___ |
| How much vinegar was added? | ___ | ___ | ___ |
| What was the container used? | ___ | ___ | ___ |
| Did the flame to go out? | ___ | ___ | ___ |
| If the last answer was yes, how long did it take for the flame to go out? | ___ | ___ | ___ |
| Did the foam cover the wick? | ___ | ___ | ___ |
| If the last answer was yes, did the flame go out before it could be covered? | ___ | ___ | ___ |
Make sure you time each of these experiments on a stop watch from the moment you add the baking soda to the moment the flame goes out.
To begin with, measure out a quarter of a cup (1/4) of vinegar in the measuring cup, then place the candle in the center of the measuring cup and light it. Now measure out a quarter of a teaspoon of baking soda and pour it into the measuring cup, being careful not to pour it onto the flame of the candle. You want it in the vinegar so that the two will produce carbon dioxide. The reason for measuring out the baking soda after lighting the candle rather than before doing so is to give the flame a little bit to get going, otherwise it might blow out before it’s strong enough to resist even the most gentle of breezes. Observe what happens to the flame as the carbon dioxide is produced. Also, observe whether or not the foam from the vinegar and baking soda reach the wick. If so, did the flame go out before this happened?
Next, place the candle in the saucepan (the saucepan should be wider than the measuring cup) and add a quarter cup of vinegar, then light the candle (make sure you either clean the candle off so it doesn’t potentially have any baking soda on it or use a different candle). Unlike placing the candle in the measuring cup after filling it with a quarter cup of vinegar, you can placing the candle in first here because your not worrying about it displacing any vinegar (hopefully you noticed that the vinegar actually rose above the quarter cup mark in the above experiment, this is because the candle displaced it and force it to rise). Now measure out and add a half teaspoon (1/2) of baking soda. Observe what happens now. The flame should slowly burn out. How high does the foam rise on the candle? How long does it take the flame to burn out?
For the final part of the experiment, pour a quarter cup of vinegar into a quart jar and then place the candle into the jar. If you’re careful you can put the candle in first and then pour in the vinegar. Light the candle. Measure out and add a half teaspoon of baking soda. Observe what happens. How high does the foam rise? Does it cover the candle’s wick? How long does it take for flame to go out? Did it go out before the foam reached the wick, if the foam did, in fact, reach the wick?
