This section introduces weathering as the process that breaks down rock and forms sediments. Students observe the chemical weathering of chalk, limestone, and marble. They then observe the physical weathering of chalk by table salt. At home, students freeze liquids in containers to observe how ice can cause the physical weathering of rocks.

Student Resources

• 7.1 Vocabulary
• 7.2 Observing Chemical Weathering
• 7.3 Observing Physical Weathering
• 7.4 Weathering by Ice
• 7.5 Section 7 Assessment

Learn by Reading

For additional content-area reading, check out the Houghton Mifflin Science eBook: Grade 4, Unit C, pages 26–27.