Keep on rockin!

We turned to our favourite material to do some rock investigations - food!
This time we used chocolate, marshmallows and biscuits.
We learned that there are 3 main types of rocks and that they are formed in different ways so we tried to simulate the formation of each one.

Igneous rock forms when volcanoes erupt and magma from inside the earth oozes out and then hardens.
We used chocolate, which we melted, and food colouring. Once it had set and hardened again we had our igneous rock!

Sedimentary rock forms through weathering and erosion forming layers of materials and sediment which then is compressed together with heat and pressure. 

We used biscuits, chocolate, chocolate chips and marshmallows to form our layers and then applied pressure to compact the layers. Next we added melted butter to cement it all together.

Crushing the biscuits.

Chocolate chips

Crushed chocolate

Adding marshmallows and compressing the layers.

Metamorphic Rock is formed when heat and pressure is applied to other rocks and it goes through changes. Once it is melted it becomes magma and the rock cycle is complete!
We used more chocolate and marshmallows for this one and heated it in the oven for a bit. We applied pressure to one half so that we could see how it changed.

After all our experimenting we had to eat the rocks! Well anything else would have been a waste! They were delicious!

There is an excellent website with an interactive rock cycle section and a quiz at the end to test your knowledge. We mostly scored very high marks in the quiz!

Find it here and have a go:

http://www.learner.org/interactives/rockcycle/index.html

To further investigate sedimentary rock we went outside and collected as many natural materials as we could find. We put them in a jar and added water. After giving it a good shake, we left it for a few days to settle. Once it settled we could see the layers very clearly.