As part of the Grade 4 students’ investigation into chemical and physical changes we have completed some small science experiments which demonstrate either a chemical or a physical change.  Did you know that when you add an acid to hot milk that there is a chemical reaction and the milk proteins clump together to make cheese?  Some of our students did this experiment.  We also watched the physical change which happens when we make butter from cream.  This is a physical change because it could be reversed if you were to mix the butter milk back into the butter.