When I first started teaching, the rock cycle was the chapter I dreaded the most - probably because my own education was lacking in that subject. Over the years, I've learned a good amount about the topic and it's come to be one of my more favorites. One thing that has really helped my students understand the types of rocks (as opposed to memorizing basic words), is an NSTA lesson I've modified. (Original lesson here:
https://learningcenter.nsta.org/resource/?id=10.2505/4/sc13_050_08_38)
There's a lot to the lesson, other than the hands-on piece, so I really encourage you to look into it. But, the main thing that I put in my lessons is the actual making of a rock using crayons.
Sediments & Sedimentary Rock: We shave a crayon down using rulers and create piles of crayon slivers. The students fold them into a piece of foil (though, waxed paper would work just as well) and take turns standing on it. Some even start twisting like a ballerina on it. :) As long as they don't let the pieces of paper shift, it will stick together like a crumbly rock.
Metamorphic Rock: This is where I really different from what the online lessons suggest. They want you to put your sedimentary rock in a foil boat and hold it over hot/boiling water until it becomes soft, but not melted. Yeah. Tried that. It melts too fast. So, I took that sedimentary rock and put it in a folded sheet of waxed paper which I then placed in a folded sheet of construction paper. Using an iron on a low heat setting (with no steam), I ironed the rock. If you do it just right, the pieces fuse together, but don't actually melt. Let it cool and then the waxed paper can be pulled apart revealing a fairly sturdy, flat metamorphic rock with a marbled surface.
Igneous Rock: Now you can make your foil boat (or I saw someone suggest foil cupcake liners) and melt the rock in your boiling pot of water that the kids aren't allowed to touch or get near. I've always used the foil boats, but every year we end up with water leaking into their boats or boats that are a wadded up mess when they bring them to me. It's horrible. I think this year I'm going to go the easy way and pick up those cup cake liners.
And then the kids can draw everything the did. I actually have them do their diagrams & labeling of the diagrams while I'm working with another group's rock. All in all, I use about 3 days of class to do this activity - 1 day per rock. We do the hands on portion and then take notes in our notebooks about that rock. I saw grades dramatically improve the year I started doing this, with no other changes to my curriculum.
