Science · Grade 3 · Earth's Landforms and Changes · Term 3

Wind and Ice Weathering

Students will explore how wind and ice contribute to the weathering of rocks and the formation of new landforms.

• Ontario Curriculum Expectations
• 2-ESS2-1

About This Topic

Wind and ice weathering reveal how these forces gradually break down rocks and create new landforms. Grade 3 students investigate wind erosion, where particles like sand blast rock surfaces, sculpting features such as mushroom rocks and sand dunes. They also explore frost wedging, the process where water enters rock cracks, freezes and expands by about 9 percent, widening fissures until rocks split. These concepts connect to familiar Canadian landscapes, from prairie badlands to coastal cliffs.

In Ontario's Grade 3 Science curriculum, under Earth's Landforms and Changes, this topic builds skills in observing change over time and comparing weathering agents. Students analyze how wind reshapes dunes through deflation and abrasion, contrast it with water's transport of sediments, and explain frost wedging's role in mechanical breakdown. Such work strengthens evidence-based reasoning and systems thinking about Earth's dynamic surface.

Active learning suits this topic perfectly since weathering processes occur slowly and invisibly in nature. Simulations with everyday materials let students witness abrasion and expansion firsthand, record measurable changes, and discuss real-world evidence. This approach shifts students from rote memorization to confident, inquiry-driven understanding of geological forces.

Key Questions

1. Analyze how wind can reshape sand dunes and rock formations.
2. Explain the process of 'frost wedging' and its impact on rocks.
3. Compare the effects of wind erosion to those of water erosion.

Learning Objectives

• Analyze how wind abrasion shapes rock formations, citing specific examples like sandblasted rocks.
• Explain the process of frost wedging, detailing how water expansion breaks rocks apart.
• Compare and contrast the erosional effects of wind and water on landforms.
• Identify landforms created or modified by wind and ice weathering in Canadian contexts.

Before You Start

Properties of Rocks and Minerals

Why: Students need a basic understanding of what rocks are made of to comprehend how they break down.

States of Matter

Why: Understanding the transition between liquid water and solid ice is crucial for grasping the process of frost wedging.

Key Vocabulary

Weathering	The process that breaks down rocks and minerals into smaller pieces, or changes them chemically.
Erosion	The process by which weathered rock and soil are moved from one place to another, often by wind, water, or ice.
Abrasion	The grinding and wearing away of rock surfaces by particles carried by wind, water, or ice.
Frost Wedging	A type of mechanical weathering where water seeps into rock cracks, freezes, expands, and widens the cracks, eventually breaking the rock.

Watch Out for These Misconceptions

Common Misconception

Wind only moves loose sand, not hard rocks.

What to Teach Instead

Wind carries abrasive particles that grind rock surfaces over time, like sandpaper. Demonstrations with fans and soft stones let students see and measure gradual wear, correcting the idea through direct evidence and peer comparisons.

Common Misconception

Frost wedging happens because ice is slippery.

What to Teach Instead

Freezing water expands in cracks, exerting pressure up to 200 atmospheres to split rocks. Hands-on simulations with clay and ice trays reveal this mechanical force, as students observe and quantify splitting, building accurate mental models.

Common Misconception

Weathering requires violent storms only.

What to Teach Instead

Daily winds and freeze-thaw cycles cause steady breakdown. Modeling activities show cumulative small effects, helping students track changes over sessions and appreciate gradual processes via repeated observations.

Active Learning Ideas

Stations Rotation: Weathering Stations

Prepare three stations: wind abrasion (fan blowing sand over clay rocks), frost wedging (clay cracks filled with water then frozen), and water erosion comparison (gentle stream over soil). Groups rotate every 10 minutes, sketch before-and-after changes, and note differences. Conclude with whole-class share-out.

45 min·Small Groups

Frost Wedging Experiment

Students form clay into rocks with intentional cracks, add water drops, and place in freezer overnight. Next day, measure crack widening and discuss expansion force. Pairs predict outcomes before repeating with varying water amounts.

30 min·Pairs

Wind Dune Modeling

In trays, students pile sand into dunes, use straws to blow air and erode shapes. Observe particle movement and deposition, then build stable dunes by adding barriers. Record sketches and measurements of changes.

35 min·Small Groups

Erosion Comparison Chart

Whole class brainstorms effects of wind, ice, and water on sample rocks. Groups test mini-models, fill shared chart with evidence like photos or measurements, and present one key difference.

40 min·Whole Class

Real-World Connections

• Geologists study wind erosion in desert environments like the Alberta badlands to understand how these forces shape the landscape over long periods, influencing land use and conservation efforts.
• Civil engineers consider frost wedging when designing roads and bridges in colder Canadian climates, as the expansion of ice can damage infrastructure and require specific construction techniques.
• Park rangers at national parks with significant sand dune systems, such as those along Lake Ontario, monitor wind patterns to manage erosion and protect fragile ecosystems.

Assessment Ideas

Exit Ticket

Provide students with two images: one showing a sand dune and another showing a rock with a visible crack. Ask them to write one sentence explaining how wind affects the sand dune and one sentence explaining how ice could affect the cracked rock.

Quick Check

Present students with a Venn diagram template. Ask them to fill it in by comparing and contrasting the effects of wind erosion and frost wedging on rocks. Prompt them with questions like: 'What material is moved in wind erosion?' and 'What causes the rock to break in frost wedging?'

Discussion Prompt

Facilitate a class discussion using the prompt: 'Imagine you are a scientist studying a new planet. Based on what we've learned about Earth, what signs would you look for to know if wind or ice weathering is happening there?' Encourage students to use the key vocabulary.

Frequently Asked Questions

How does frost wedging work on rocks?

Water seeps into cracks in rocks, freezes into ice, and expands by about 9 percent, widening the cracks until the rock splits. This mechanical weathering is common in Canada's cold climates, contributing to talus slopes and scree fields. Students can model it safely with clay to grasp the expansion force without real rock hazards.

What are Canadian examples of wind weathering?

In Alberta's Badlands, wind abrasion carves hoodoos and smooths sandstone. Near Great Lakes dunes, deflation hollows bowls and deposits ridges. These sites offer virtual tours or local field sketches for students to connect curriculum to real landforms shaped over thousands of years by persistent winds.

How can active learning help teach wind and ice weathering?

Active simulations, like fans eroding clay or freezing water in cracks, make invisible processes visible and measurable. Students in small groups predict, test, and revise ideas, fostering deeper retention than diagrams alone. Collaborative charting of results builds discussion skills and reveals patterns, such as wind's polishing versus ice's fracturing, aligning with inquiry-based Ontario expectations.

How does wind erosion differ from water erosion?

Wind lifts and blasts fine particles for abrasion, effective on dry surfaces but limited by low density. Water dissolves minerals, carries heavier loads, and undercuts bases. Classroom models with fans versus streams highlight these: wind smooths tops, water gouges channels, helping students classify effects with evidence from their tests.