Book 5, Question 69 · Video
Crack and Crumble! Another Look: How Weather Breaks Rock
Rock is tough, but weather works on it slowly. Water, wind, heat, and cold can all wear it down, and even plant roots can push into cracks. Bit by bit, big rocks turn into smaller
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What Crafty Clover says in this video
Intro
Hi! I'm Crafty Clover! Let's discover something amazing. Why does weather break rock?
The Big Idea
Ice isn't the only way weather breaks rock. Heat, plant roots, and rain do it too! A boulder can split with no hammer at all. Every day, tiny changes make rock weaker. Let's meet three sneaky rock breakers!
Step 1
Step one: hot days and cold nights. In the day, the sun heats a rock and it swells a tiny bit. At night it cools and shrinks. After thousands of days, this stress can crack or flake the rock.
Step 2
Step two: roots pry open cracks. A seed lands in a crack, and sprouts. As the root grows thicker, it pushes the rock apart, like a slow wedge. Even strong trees can grow out of solid rock.
Step 3
Step three: rain slowly dissolves rock. Rain picks up a gas from the air, carbon dioxide, and becomes a very weak acid. Over time, it eats away at some minerals. This is chemical weathering.
A Closer Look
Let's see all three at work. The sun heats the rock, and the cold night shrinks it again. A tree root grows into a crack, and pries it wider. And rain seeps in, dissolving some of the rock.
Quick Facts
Quick facts! In deserts, rocks get very hot by day and cold at night, so they can crack and flake. Tree roots can lift sidewalks and split boulders. Plants are strong! Weathered rock crumbs eventually become sand and soil. Grown-up note: stay clear of the bottom of cliffs, because falling rock is weather at work.
Think Like a Scientist
Now, think like a scientist! Try this with a grown-up. Look for a crack in a sidewalk or a wall. Can you find a plant growing in it? What job is the plant doing to the crack?
Outro
So weather breaks rock with heat, roots, and rain, a little bit every day. Amazing, right? Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!