The cycle isn't random. Each family is made by a particular run of processes, and the sedimentary path in particular is a clean five-step sequence worth knowing cold.
How Each Family Is Made
Igneous is the cooling family — molten rock loses heat and minerals lock into crystals. Cool it slowly deep underground and the crystals grow big (granite); cool it fast at the surface and they stay tiny (basalt). Crystal size is a clue you can see. Sedimentary is the layering family — broken bits, piled, buried and glued (the five steps below). Metamorphic is the cooking family — bury any rock deep and heat and crushing pressure re-grow its minerals into a new, denser, often banded rock without melting it. That “without melting” is the whole point: melt it and you'd be back to igneous.
The Five Steps That Build a Sedimentary Rock
This is the sequence to memorise, in order:
One — weathering. Rock at the surface is broken down where it sits, by frost, water, wind, plant roots and chemical attack, into smaller and smaller bits.
Two — erosion. Those loosened bits are carried away by water, wind or ice.
Three — deposition. The bits are dropped somewhere new, usually where the moving water or wind slows down — a river mouth, a lake bed, the sea floor.
Four — compaction. Layer piles on layer, and the weight squashes the lower sediment, squeezing the water out and packing the grains tight.
Five — cementation. Minerals dissolved in the water crystallise in the gaps and glue the grains together into solid rock.
A Worked One, Slowly
Question: trace the path from a granite mountain to a layer of sandstone, naming each process.
Start with igneous granite at the surface. Frost and rain weather it, cracking it down to loose sand. A river erodes that sand — picks it up and carries it downstream. Where the river meets the sea and slows, it deposits the sand on the seabed. Over thousands of years more sand buries it, and the weight compacts the lower layers. Water seeping through leaves mineral cement that cements the grains, and now you have sedimentary sandstone — once a mountain, now a flat stripe of rock. Name each verb in order and you've traced the cycle perfectly. Drag the stages in the toy to feel the sequence lock into place.