Lesson 10 of 19
Slow changes in rocks
Show on a big screenRock and soil slide down a hill in a landslide. The landslide leaves a pile of stones. What made them?
Loading lab…
The idea
Step 1 of 4
- One big rock.
- A crack opens.
- It breaks into smaller pieces.
- Over time it becomes sand and small stones.
Big rocks break into stones, very slowly.
Weathering is the slow breaking or changing of rocks. It forms soil.
- Physical: frozen water in cracks and tree roots split rocks. Heat and cold split them too.
- Chemical: water can react with a rock. Black rock with iron can form a red layer of iron oxide. Iron oxide is iron joined with oxygen.
Erosion is wind or flowing water carrying broken rock away. It is a physical change.
The rule
Rocks break in physical changes. Some rocks change into new substances. Most of these changes are slow.
These changes can take thousands of years. They are not undone.
Try the lab to finish this lesson.