Air?

Today, we did another experiment that was dealing with fire.We put the same liquid (ethyl alcohol)we used last time about thermal expansion, we put it in a container and we lit up a candle and burned the liquid.After all the fire was gone, we stuck a candle inside to see if it would still be lit.Once we put it inside it just stop burning.The carbon dioxide stopped it because fire doesn't need it but it needs oxygen,fuel, and heat to burn.Then after we were done, Mr.L told us that carbon dioxide has more weight than oxygen and then he showed us by pouring the carbon dioxide in another container then stuck a candle in the old container to show that the candle could still be burning because there was no more carbon dioxide in there, then he put the candle inside the container he poured it in and it didn't lit!I was really surprised that you can pour the carbon dioxide, I thought that the carbon dioxide would flow around like oxygen but i was wrong.The carbon dioxide was just like water, you could pour it and it would go right inside

-Steve