Our third graders in Michigan are charged with learning the rock cycle. Several parents complain that this is a subject that is very difficult for their child to grasp. Many teachers in my team hate to teach this unit for the same reason. I, however, LOVE this unit. It costs me a lot of money to teach it, but it is worth every penny. I use what every child or any person for that matter loves to teach the rock cycle. That item that we all love is...FOOD!
One activity I love to do is what I have phrased "The Dorito Rock Cycle Experiment"! Students are given a handful of the yummy Doritos to use as their "Boulders". I chose this chip because of the shape, which reminds me of a boulder, and the cheese, which represents sediment quite well. We start by taking one Dorito and breaking of a little piece and sketch the new look our "boulder" has. We take another chip and take our hand and press on it crushing it into many pieces. We then sketch this boulder. We take the next "boulder" and place it in a baggy and pound the living daylights out of it...this will be our sediment. We repeat that in another baggy and then we add water and watch how the sediment clumps together and when we add a little pressure to this it becomes a layer that will eventually become part of a sedimentary rock.
Having the students keep each stage of our Dorito weathering and erosion process helps my third graders see that a rock goes through many changes. When all the sketches are finished and we write about what we just did at each step the students are allowed to eat all of the Doritos left. This is one of the most popular experiments I do in my room. I think it is important that you give the students more than one Dorito so they can see the process, but I also think you need to give them enough so there are a few they can eat as well! When students are asked to describe the rock cycle this experiment helps them remember what the process is and it stays with them forever. Way better than any worksheet I can think of to use.