A canyon is a deep, steep valley with a river at the bottom. Some are so big you could fit a whole HDB block inside — and a tiny river made them!
Let's find out how water — drip by drip — cuts through solid rock. Tap Next to begin! 👉
Rain falls on high ground — like hills and mountains. Water can never sit still on a slope. It always rushes downhill, joining up into a stream, then a river.
Plain water is quite gentle. The real secret is what the river carries with it. Tap each tool to find out what it does:
This wearing-away by water and the grit it carries has a name: erosion.
A river removes only a tiny bit of rock each year — thinner than your fingernail! But it never stops. Drag the slider to fast-forward through time and watch the canyon grow.
Drag me! 👆
Rock comes in layers. Soft layers wash away quickly, but hard layers fight back and wear away slowly. This is why canyon walls look like a giant staircase.
Tap the layers to order them from fastest-eroding (1) to slowest-eroding (3):
A river canyon is very deep but quite narrow. Why doesn't it get just as wide as it is deep?
🎯 Exactly! The river digs down, so the canyon grows deep before the walls slowly crumble and widen.
Rivers + grit + lots of time = canyons 🌊⏳🏞️
Let's recap the 4 big ideas:
Next time you see a river, remember — it's slowly drawing a canyon, one grain of sand at a time. Well done! 🎉