Weathering: Breaking Down Rocks

What You'll Learn

The rock cycle shows how rocks change from one type to another. Igneous rocks form from cooled magma, sedimentary rocks form from compressed sediment, and metamorphic rocks form under heat and pressure.

Key Words

evaporation
condensation
precipitation

Materials Needed

rain gauge
cotton balls
food coloring
clear container
rocks
sand

Safety First

Wear safety goggles when mixing liquids.
Wash hands after handling materials.
Be careful with scissors — ask an adult for help if needed.

Steps

Step 1 — Read

Read the introduction and identify the main idea of this lesson.

Step 2 — Do

Test rock hardness using Mohs scale: try scratching rocks with your fingernail, a penny, and a nail. Rank them from softest to hardest.

Step 3 — Observe

Use your senses (except taste) to describe what you notice.

Step 4 — Record

Write a summary of your findings in 3-5 sentences.

Check Your Understanding

Question 1

1 of 3

What causes weathering?