Sedimentary, igneous, metamorphic...which is which and what do they mean anyway? 

Sedimentary rocks are pressed together by pressure over time, igneous rocks are formed by a combination of heat and pressure, and metamorphic rocks by extremely high heat (think cooled lava). Just learning the facts can be hard to remember but when you make all three types of rock out of Starburst candies this lesson becomes fun, and much easier to understand. I like the directions given here.

You can go here for a chart showing common rocks and what type they are. For further fun, take it outside and use a hammer to break open common pebbles that you find (under adult supervision please!) and look at the inside to see if you can tell what type of rock they are. Use your rock chart to see if you can identify the rocks.  You can also check out more resources on Hoopla to dig deeper.