Physical and chemical weathering

1. Physical and chemical weathering

2. Weathering-breaking down rocks • Two types: • 1. Mechanical weathering-just breaks it down and does not have a chemical change • 2. Chemical weathering-the rock’s minerals change into different substances

3. BrainPOP-weathering • http://www.brainpop.com/science/weather/weathering/

4. Mechanical weathering • Causes: • 1. Ice wedging- water freezes in cracks and expands breaking the rock • 2. Animals digging (claws) • 3. Plant roots growing (pressure)

5. Chemical Weathering • Causes: Reactions • 1. rainwater (acid rain) • 2. oxygen (reacts with iron-makes rust) • 3. carbon dioxide • 4. acids of plant decay. • 5. sulfuric acid

6. pH scale

7. pH scale • Acidic is below 7 • Alkaline (or base) is above 7 • Neutral is 7 • Find your examples from the pH scale substances listed in that area for your notes

8. BrainPOP- pH scale • http://www.brainpop.com/science/matterandchemistry/phscale/

9. Table 2 (worksheet) • Lab experiment: Chalk in vinegar • Record what it looks like at start • Watch overnight • What does chalk look like next day

10. Table 3 (worksheet) • Examine sugar cube at start • Examine sugar cubes after shaking 20 times • Examine sugar cubes again after shaking 20 times

11. Table 1 (worksheet) • 1-tap water • 2-rainwater • 3-lemon juice • 4 cola • 5 ammonia