Why Do Rivers Curve? | Weathering & Erosion Science Investigation

Engage students in exploring weathering, erosion, and changes to Earth’s surface through the intriguing phenomenon: Why do rivers curve?

In this Grade 4 science investigation, students begin by sharing their initial ideas and questions about the phenomenon. As they learn about weathering and erosion, they return to the guiding question and revise their thinking based on new information and evidence. 

Students participate in a hands-on Sugar Cube Shake investigation that models mechanical weathering through abrasion. They make predictions, observe changes over repeated trials, record data, and use their observations as evidence for understanding how Earth materials can change over time. 

Throughout the lesson, students are encouraged to think like scientists by asking questions, making observations, comparing ideas, and using evidence to develop explanations. The investigation concludes with a Claim-Evidence-Reasoning (CER) assessment in which students bring their learning together to explain why rivers curve. 

Designed to support NGSS 4-ESS2-1, this ready-to-use lesson combines science content, student investigation, discussion, and evidence-based reasoning in an engaging learning sequence.

Included in this resource:

• Teacher lesson plan and teaching guidance

• Weathering and erosion presentation with teacher notes

• What Do I Wonder? and My Thinking Is Changing student pages

• Weathering and erosion vocabulary activity

• Weathering vs. erosion compare-and-contrast activity

• Sugar Cube Shake hands-on investigation and student data sheet

• Erosion Detective observation activity

• Why Do Rivers Curve? CER assessment

• Teacher answer key and sample responses

• Product preview