What we did in Mrs.Gentrys class was first we reviewed the yellow paper and we learned that a chemical change is when it changes into a new substance.A pysical change is when it just changes it's form but not it's substance.Then we did an experiment and we pored in some chemicals and some food coloring then when we were done we took the bottle outside and shook it up and then we put it on the ground and opened it and it started pouring out and exploding.We called it elephant toothpaste.Then we went back inside and we wrote down what we used and what happened when we shook it up and opened it.