Science of rocks

Last week we examined rocks and tried to determine what type of rock they were. There are three types of rocks, sedimentary (rocks formed from sand packed together), Metamorphic rocks (rocks formed from rocks that were morphed into another by heat and pressure), Igneous rocks (rocks formed by cooling lava or magma). Out of those rocks we determined that they were Igneous rocks because there are crystals inside meaning that it hade to be cooled to be a rock so it has to be igneous. Then we did an exp. that showed the faster you cool a rock the less crystals there will be in the rock.