Toady we looked at two different methods for evaporating the solvent out of a solution, leaving only the solute behind:
The method on the left was much slower, and it made blue crystals of copper sulfate. The method on the right was much faster but it left a white powder. This was still copper sulfate, though. When we added water to the white copper sulfate powder, it made a blue solution again!!
This idea of slow cooling and fast cooling helps us understand how different types of rocks are formed. For example, marble and limestone are two very different rocks but are made of the same chemical (calcium carbonate).