Friday 22nd September

This week in Science we were, once again, learning about rocks. First of all, we recapped last week’s lesson and reminded ourselves of the six rocks we learnt the names of (limestone, marble, slate, sandstone, granite and chalk). We then looked at a Power Point which explained that all natural rock can be categorised into one of three groups. One group of rocks is formed by magma bursting out from the Earth’s mantle, through a volcano, and cooling on the Earth’s crust (igneous rocks). Another group of rocks is formed through layers of dead creatures, eroding rocks and debris settling on the bottom of the sea and being squashed down by more layers (called layers of sediment) of the same things (sedimentary rocks). The final group of rocks is made when sedimentary and igneous rocks are fused together through intense heat and pressure (metamorphic rocks).After learning about the different types of rocks a rock can be, we wanted to find out what some of our six rocks we learnt the names of last week could be categorised as. To do this we carried out some tests. Test 1 explored the hardness of each rock and using lollipop sticks we sort to find out whether our rocks would crumble easy, like a sedimentary rock would do. Test 2 meant dropping water on our rocks to see if they were permeable (would let the water soak through). Igneous and metamorphic rocks are impermeable whereas sedimentary rocks are permeable. Test 3 involved dropping vinegar onto our rocks to see if the acid would make them fizz, like what would happen if you did this to some sedimentary rocks. After all our tests had been completed we regrouped as a class and discussed our results. The three rocks we tested today were granite, which we discovered is an igneous rock, slate, which we discovered is a metamorphic rock, and sandstone which we discovered is a sedimentary rock.