In tis chapter I learned that hydrogen can explode when you light it.  I also learned about exothermic and endothermic reactions. An exothermic reation is a reaction that gives off more energy than is taken in. An endothermic reaction is a reaction that takes in more energy than it gives off.  Another thing I learned is a way to extract sugar from water, by evaporating all of the water.  I liked all of the lab experiments that had a BIG reaction. What I liked least was when we had to clean up a lot of oil in the oil expeiment. One question I have is, what two elements can be mixed together to make it explode. If you find an answer tell me because I want to know.