Carbon Dioxide Dangers Demonstration Model

Dina:    Hi. I’m Dr. Dina. I work with the U.S. Geological Survey in Menlo Park, California with the Volcano Hazards Program. Today, we’re going to do an experiment using vinegar and baking soda to look at some of the dangers of carbon dioxide. What we’re going to do is we’re going to show why it’s not a good idea to be in a depression in an area where there’s carbon dioxide gas.

So we have three candles in our bowl and they’re all at different heights and you might think of the different heights of candles as maybe one being on top of a mountain, maybe one being in a depression in the earth. So what we’re going to do is we’re going to see what happens when the CO₂ is added to the bowl.

So the first thing we’re going to do is make our carbon dioxide gas. We’re going to use a quarter cup of vinegar and I’m using a tall container to put it into and I have a glass lid ready. Then we’re going to add a teaspoon of baking soda. All of these are easy ingredients to find in a supermarket.

So we mix the baking soda and vinegar and we put a lid on to trap the gas. So you can see there’s a reaction going on and you can see all the bubbles. So we’ve made our gas and now, what we’re going to do it is we’re going to slowly pour it into our container and watch what happens without pouring the liquid in.

Here we go. In that time, all the candles went out and you could see that they went out in order based on their height as the CO₂ displaced the oxygen and pushed the oxygen up and out so the container is open so the oxygen comes up and out and the CO₂ basically is pushing the oxygen out, and as the oxygen leaves the candles go out because they can’t burn without the oxygen.

So what you just saw was all the candles going out, and they didn’t go out in a random order. They actually went out based on where they were in relation to the carbon dioxide gas. So the candles going out gave us an idea of where the oxygen wasn’t.

This experiment illustrates one of the hazards of CO₂. In the Long Valley Caldera area in eastern California, there is a lake called Horseshoe Lake where CO₂ is coming up out of the ground. The CO₂ is coming out of the ground from magma at depth and it’s known to collect in low-lying areas.

As we saw in our experiment, the CO₂ is heavier than air and can displace the oxygen. So the low-lying areas where the CO₂ collects can be very hazardous to animals and people; it can even kill you.

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