Science Rocks (Sorry!)

Sorry,...couldn't resist the pun! So, there are lots of ways to demonstrate the rock cycle: cakes, melting jelly beans...but many of them are demonstrations rather than hands-on activities that the children can really get into. 

Anyway, I had an idea. Unsurprisingly, I was eating chocolate when it came to me (how many of my ideas have been inspired by food or drink?)
The leg-work comes in grating bars of white, milk and dark chocolate

I put this into bowls in the middle of each table and told the children that it was sediment. (We'd had a look at a diagram of the rock cycle first). They spooned layers of each into little pots lined with cling film. This represented the layers of sediment building up over time. ​

​They then wrapped the cling over the top and pushed down hard - applying the pressure seen in the rock cycle. The do need to push really hard for about a minute. 

​We then used the cling film to lift out the 'rocks' and broke them open to see what had formed. I was thrilled with what we saw!

Voila! Sedimentary rock - made by applying pressure to layers of sediment. They even had the crumbly texture of sedimentary rocks. At each stage, the children drew diagrams of what formed and noted how. 

Next, we wrapped the 'rocks' back up in their cling film, then applied heat and pressure by squashing and squishing them (technical terms!). We did this for a couple of minutes whilst talking about the heat from our hands. We unwrapped them and...metamorphic rock! You can still see the different parts of the original sediment.

​To create the igneous rock, we wrapped them back up and dipped them into warm water, then applied pressure by squishing them again. We discussed how, for chocolate, this was extreme heat and pressure. I was worried that it might get very messy here (not that it would have put me off!) but it actually didn't, because, naturally, the water wasn't too hot. 

​I loved this project! It really showed the children how different rock types form and that a rock can move from one type to the other under the right conditions. We had so much fun with this hand-on science lesson and the children really gained a good understanding of how rocks form. This helped a lot when we moved on to fossil formation and they had no trouble suggesting reasons for fossils being most common in sedimentary rock.