Glaciers: The Slow Sculptors

Introduce the driving question: Why does a glacier shape a landscape? Show a photo-like text description of a glacier-carved valley.

• Glaciers are slow-moving rivers of ice.
• They leave behind dramatic landforms.
• Let's investigate how.

Use the simulation to predict how changing ice thickness and slope affects the valley shape. Will it be V-shaped or U-shaped?

• Adjust ice thickness and slope.
• Observe the resulting valley cross-section.
• Form a hypothesis before seeing the answer.

Examine diagrams of a river-carved valley and a glacier-carved valley side by side. Note the differences.

• River valleys are V-shaped.
• Glacier valleys are U-shaped.
• Glaciers also leave behind scratches (striations).

Explain plucking (ice pulling rocks away) and abrasion (rocks embedded in ice scraping the ground). Show how these create U-shaped valleys and other features.

• Plucking: ice freezes to rock and pulls it out.
• Abrasion: rocks in the ice sandpaper the bedrock.
• Over time, a V-shaped valley becomes a U-shape.

Clarify that glaciers only affect landscapes where they flow. Tectonic forces, rivers, and wind also shape the land. Glacial features are distinctive.

• Glaciers do not create all valleys.
• Only areas with thick, moving ice get sculpted.
• Other processes like rivers create V-shaped valleys.

Test your understanding: After a glacier melts, which feature would you expect to see?

• Apply what you learned to a new situation.
• Choose the correct glacial feature.

Directly answer the driving question: Glaciers shape landscapes by eroding rock through plucking and abrasion, carving U-shaped valleys, cirques, and leaving behind moraines. The slow but steady movement of ice transforms mountains over thousands of years.

• Glaciers are powerful erosional agents.
• They create distinct landforms like U-shaped valleys.
• Now you understand why a glacier shapes a landscape.