Some crystals are formed when molten rock cools and hardens. Others are formed when water containing dissolved minerals evaporates. In both cases, the atoms of the minerals form solids by coming together in regular repeating patterns. These repeating patterns make crystals both strong and hard. Crystals of the same mineral always follow the same growth pattern.
Crystals are easy to make and observe with the naked eye, a magnifying glass, or a microscope.
Each of those tools reveals a different level of complexity in the specimen. This activity introduces students to crystal structures and a new way of looking at things. If your students are proficient at using microscopes, then they can now investigate some special properties of crystals. In this activity, students will design investigations about crystals. If they are trying to find out how different variables affect crystal growth, they need to first identify the variables they will be studying.