When we are mixing vinegar and baking soda, we get a foamy reaction that produces carbon dioxide. You can't see it, but we can actually fill a glass with it because carbon dioxide is heavier than air. When I pour concentrated carbon dioxide onto candle flame, it pushes oxygen away from the candle and flame goes out in an instant. More science experiments for children on my youtube channel https://www.youtube.com/c/thedadlab | TheDadLab