Download Physical and chemical weathering

Physical and chemical
weathering
• 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
BrainPOP-weathering
• http://www.brainpop.com/science/weather/
weathering/
Mechanical weathering
• Causes:
• 1. Ice wedging- water freezes in cracks and
expands breaking the rock
• 2. Animals digging (claws)
• 3. Plant roots growing (pressure)
Chemical Weathering
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Causes: Reactions
1. rainwater (acid rain)
2. oxygen (reacts with iron-makes rust)
3. carbon dioxide
4. acids of plant decay.
5. sulfuric acid
pH scale
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
BrainPOP- pH scale
• http://www.brainpop.com/science/matterand
chemistry/phscale/
Table 2 (worksheet)
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Lab experiment: Chalk in vinegar
Record what it looks like at start
Watch overnight
What does chalk look like next day
Table 3 (worksheet)
• Examine sugar cube at start
• Examine sugar cubes after shaking 20 times
• Examine sugar cubes again after shaking 20
times
Table 1 (worksheet)
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1-tap water
2-rainwater
3-lemon juice
4 cola
5 ammonia