This is a fun way to get kids excited about rocks. Divide your rocks into three samples (sedimentary, metamorphic and igmeous). Then allow students to look at and talk about each set. They will have to use the properties about rocks and the information that you have taught them in class to figure out what types or rocks are in each set. Then they must provide a scientific explaination as to how they classified each set.
My students LOVE this activity!!!