demonstrations:chemical_weathering
Chemical Weathering
Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Rocks, Soil and Erosion
Alternative titles: Acid Rain and Rock Breakdown
Summary
This demonstration shows how acid can chemically weather sedimentary rocks. Vinegar simulates acid rain reacting with chalk or limestone, representing how minerals in rocks break down and form new materials.
Procedure
- Place a piece of chalk or limestone at the bottom of a clear plastic jar.
- Carefully pour vinegar into the jar until the chalk is fully submerged.
- Seal the jar with its lid.
- Observe the chalk or limestone as bubbles form and its surface begins to change, representing the breakdown caused by acid rain.
- Record observations and compare predictions with results.
Links
Chemical Weathering: Acid Rain - AusEarthEd:
📄 Demonstrating Chemical Weathering - iTeachly: https://iteachly.com/demonstrating-chemical-weathering/
Variations
- Compare the effects of vinegar with plain water to highlight the role of acid.
- Test different acidic liquids (such as lemon juice) to observe varying intensities of weathering.
Safety Precautions
- Safety goggles required.
- Handle vinegar carefully; avoid spills and skin contact.
- Do not lean over the jar when pouring vinegar.
- Dispose of materials safely after the experiment.
Questions to Consider
- What does the chalk represent in this activity? (Sedimentary rock such as limestone.)
- Why does vinegar cause the chalk to bubble? (The acid reacts with calcium carbonate, releasing carbon dioxide gas.)
- How is this similar to acid rain affecting real rock formations? (Acid rain reacts with minerals in rocks, breaking them down and changing their structure.)
- Which environments would experience more chemical weathering? (Warm, wet climates accelerate chemical reactions and increase weathering rates.)