Rock Testing and Classification

Students test rock samples for properties such as hardness, luster, texture, porosity, and reactivity. They record observations, classify each sample as igneous, sedimentary, or metamorphic, and connect their findings to real-world engineering challenges.

1. Introduce the three main rock types (igneous, sedimentary, metamorphic) and the rock cycle.
2. Provide each group with a rock testing kit containing samples, tools, and data sheets.
3. Explain how to test for properties such as:
   • Hardness (scratch tests with steel nail, penny, glass, quartz)
   • Luster (shiny vs. dull surface reflection)
   • Streak (color of mineral powder on unglazed tile)
   • Texture (granular, smooth, porous)
   • Reactivity (vinegar or weak acid bubbling on carbonate rocks)
   • Magnetism (test with a magnet)
   • Density/buoyancy (float test for pumice)
4. Have students record their results in a Rock Test Data Table.
5. Use a flow chart or guide to help students classify each sample as sedimentary, igneous, or metamorphic.
6. Relate results to the engineering problem: selecting the best rock type for designing underground caverns.
7. Conclude with a class discussion on why knowing rock properties is essential for building and safety.

Identifying Rocks and Minerals - Using Physical Properties for Identification - Miacademy & MiaPrep Learning Channel:

📄 Rocks, Rocks, Rocks: Test, Identify Properties & Classify - ncwit.org: https://www.teachengineering.org/activities/view/csm_asteroid_lesson5_activity1_tg

• Use local rocks collected by students and compare them to reference samples.
• Have students research common rocks in their own region using a geology map.
• Extend the activity by relating tested rocks to famous landmarks or building materials.

• Wear safety goggles during scratch tests and acid tests.
• Handle hydrochloric acid or vinegar with care; use only small amounts.
• Wash hands after handling rock samples and testing chemicals.
• Supervise closely when using steel nails, glass, or other sharp tools.

• Why is hardness an important property when classifying rocks? (It helps identify minerals and suggests durability for construction.)
• How does porosity affect whether a rock would make a good building material? (Porous rocks may allow water to seep in, weakening structures.)
• Which rock type is most likely to form near a volcano? (Igneous.)
• What processes turn sediment into sedimentary rock? (Deposition, compaction, and cementation.)
• Why do engineers need to understand rock properties before building tunnels or caverns? (Safety, stability, and feasibility depend on rock type.)