This week in science we learned how to tell which rocks were igneous, metamorphic, or sedimentary. Igneous rocks might have crystals, metamorphic rocks are sometimes smooth, and sedimentary rocks break eaily.


One question asked in class was, "Can one type of rock turn into another type of rock?" I think that one type of rock can turn into another. The other question asked was "What has to happen for this to occur?" I think for this to happen subduction needs to occur. If there is one small plate that has metamorphic and sedimentary rock on it and another bigger plate collides into it then the smaller plate will be forced under the bigger plate. When the smaller plates is forced under the bigger one then the small one will melt down into magma. When that plate is melted everything on that plate will melt to. So those metamorphic and sedimentary rocks will melt. When the bigger plate cracks, magma will come up through that crack. That magma is made up from the melted sedimentary and metamorphic rocks so when it goes through the crack, it will cool. When the magma cools, it will turn into igneous rock. That igneous rock was once seimentary and metamorphic rock.


Also metamorphic and igneous rock can turn into sedimentary rock. If there is a land formation made up of metamorphic rock or igneous rock then it can be eroded. When the formation is eroded then those tiny pieces of the formation will get into the rivers and the rivers will bring it to a deposition zone. When the tiny pieces of metamorphic and igneous rock get into the deposition zone they get stuck together and form a rock. The rock that was once metamorphic and igneous is now sedimentary rock.


On Friday we learned that sometimes we have to break open a rock to see what kind of rock it is. The outside of the rock might be normal and look like cement but if you break it open, it could have crystals forming. That means the rock is probably igneous but if someone just looked at the outside they might not have known that.