We made the landforms visual I got off from here: gingersnaps blog and then I just had them pre-cut for the kids. We used card stock to glue them to and the kids just colored and designed them (adding elements like volcano lava spewing out and little river running down the mountainside. Then they layered them onto the card stock gluing them one at a time. Here is the finished product for that and the rock experiment is further down below:
The next thing we did was take that "sediment" and put it together into a piece of tin foil. The kids then squeezed it together and then stepped on it to create metamorphic rock with the final touch being to add some "heat" - we did this with an electric water kettle. We placed some water into a bowl and then let their crushed "rock" sit in the tin foil on top of the water for a few minutes until it became soft. Then they quickly took and further smashed it down. This became the metamorphic rock.
Lastly, we took our metamorphic rock and we added boiling water from our teapot to the bowl and quickly placed our tin foil filled "metamorphic" rock on top and waited for it to melt the crayon till it was a thick liquid. We quickly removed it and placed it in the refrigerator to cool quickly. This became our igneous rock. Here was the final result: