P4 -7 became geologists today by modelling the rock cycle. The natural rock cycle can take millions of years to achieve. We simulated this entire process in an afternoon using chocolate.
Sedimentary Rock
We started off by making sedimentary rock that had been broken down into smaller pieces by the elements. To do this, we:
- Grated milk and white chocolate into flakes to represent different rock types
- We built up our sediment in a pile on tin foil
- It was then compressed by pressing down on the flakes wrapped in the foil
- The resultant sedimentary rock sample can be seen in photographs below
- The separate sediment deposits can be observed as white and dark sections.
Sedimentary Changing To Metamorphic Rock
We then simulated high pressure and heat being applied to our sedimentary rock sample. We achieved this by:
- Putting our sample in a bag along with whole chunks of chocolate.
- We squashed and squeezed the sample and let our body heat do the work
- The results can be seen below. A harder, grainy texture is achieved as a result of changing from sedimentary to metamorphic rock.
Metamorphic rock changing to Igneous Rock
To model the change from metamorphic rock to igneous rock, we:
- Melted the chocolate over a Bain Marie.
- The metamorphic rock melted as if it was exposed to extreme heat under the crust of the earth, becoming magma.
- The melted sample was then cooled and formed in a flow, just like lava erupted from a volcano.
The cycle will start all over again with igneous rock breaking down to form sedimentary rock and so on…
