The Rock Cycle for Kids: How Rocks Change From One Type to Another (Grade 6 and 7 Science)

Hi, I'm Luna from DoodleBeez. Rocks seem like they never change, but over thousands to millions of years, they do. Today we are exploring the rock cycle, the slow loop that turns one type of rock into another.

Igneous rock forms when melted rock cools and hardens. Magma that cools slowly underground makes big crystals, as in granite. Lava that cools quickly at the surface makes tiny crystals, as in basalt.

At the surface, wind, water and ice slowly break rock into small pieces called sediment. This is weathering. Rivers and glaciers carry the sediment away, which is erosion, and drop it in layers.

Layer after layer piles up. The weight above presses the layers together. This is compaction. Minerals in water then glue the pieces together, called cementation. The result is sedimentary rock, like sandstone.

When rock is buried deep, great heat and pressure squeeze it. The rock does not melt, but its minerals change and line up. It becomes metamorphic rock. Shale can become slate, and limestone can become marble.

Any rock can become any other type. Rock that melts becomes magma again. Energy from the Sun drives weathering at the surface. Heat from inside Earth drives melting and metamorphism deep down. The cycle never ends.

Now it's your turn. A layered rock is buried very deep. Heat and pressure squeeze it for a long time, but it never melts. What type of rock forms? Pause and try. Metamorphic rock!

Great job! Remember, igneous rock forms from cooling melted rock, sedimentary rock from pressed and cemented layers, and metamorphic rock from heat and pressure. Practice the rock cycle in the Science Lab at doodlebeez.com. See you next time!