16. Materials needed for each group: 1.Chalk for each student 2.Small piece of sand paper 3.Small cup of vinegar per group 4.Hand lenses

17. Management prior to lab: Have chalk broken into small pieces and cut up the sandpaper into pieces large enough to hold. The vinegar can diluted with water to slow the reaction down to make it more realistic.

18. Procedure: You are going to complete two activities that model how minerals can be weathered. Distribute chalk and sandpaper. Chalk is a soft sedimentary rock made of calcite and the sandpaper has the mineral quartz glued onto it. Use your hand lenses and observe both the sandpaper and the chalk. Record your observations in your journal.

19. Now hold the sandpaper steady and carefully scrape the chalk across it. Now observe what you notice about the chalk and the sandpaper. Record your observations. This is an example of “physical weathering”. The sandpaper (quartz) is a harder mineral and scratched the softer mineral calcite (chalk). In the natural world when sand is blown against rock, abrasion (cuts) occur on the rock. Use the next slide for discussion questions.

21. Now take the small cup of vinegar. Place your piece of chalk into the vinegar. Write your observations. After 5 minutes your teacher will remove the vinegar to stop the reaction. Draw and write what you see now. We are going to now put the chalk back into the cup and see what happens over a period of time. This activity models “chemical weathering”. Use the next slide for discussion questions.

23. Conclusion Statement How are these experiences like the weathering on the Earth’s surface? How are they different? What are you wondering now?