1. Acid Rain
D. Crowley, 2008

2. Friday, November 23, 2018
Acid Rain
To know how acid rain is formed

3. Rock Weathering
Complete the rock weathering worksheet

4. Rock Weathering

5. Rain
Normal rainwater has a pH of around 5.6 – this means it is naturally slightly acidic
This natural acidity is due to CO2 which dissolves in rainwater, forming carbonic acid
Rainwater with a lower pH than normal is called… acid rain!
We can test the pH using Universal Indicator (remember, green is pH 7 (normal); red for pH 1 (acid); and purple for pH 14 (alkali)

6. Acid Rain Acid rain has a higher than normal acid level (a low pH)
Acid rain may contain weak solutions of carbonic, sulphuric, and nitric acids
Where it falls over a prolonged period it can cause damage to the environment…

7. Naturally
These chemicals can occur naturally, for example sulphur is released at active volcanic sites
However, the vast majority of these chemicals are pollutants, produced from cars and power stations
When these dissolve in rainwater they produce strong acids (sulphuric acid and nitric acid) forming acid rain

8. Acid Rain

9. Effects Of Acid Rain
Trees lose some of the protection in their leaves, leaving them more at risk from frost and diseases
Tree roots may also become stunted, so they can't take up as many nutrients
Soils lose some of their nutrients

10. Effects Of Acid Rain
Increasing acid levels may cause problems for aquatic animals and plants (e.g. fish may have trouble breathing)
Acid rain may dissolve the stonework and mortar of buildings causing structural problems

11. Pollution
Acid rain pollution may also cause acid rain many miles away from the source
Pollution controls were introduced in the US in the 1980s, after Canada claimed that its forests were being harmed by US pollution
Highland areas (where the rainfall is higher) are particularly susceptible to acid rain – high levels of acid rain in Scandinavia are believed to be caused by pollution originating in other countries…

12. Pollution
In many European countries up to one half of the total area of forests have been damaged by acid rain - in particular, in Germany's Black Forest more than 50% of the forest has been severely damaged by acid rain
Many trees have dried out and died already, while many others have discolored leaves
Even tree planting has failed to halt this destruction, since the soil is already acidic

13. Unfair
Scandinavian countries such as Sweden and Norway do not contribute much to atmospheric pollution
However they are suffering extensive damage from atmospheric pollutants carried there from other countries

14. Reducing Acid Rain
Sulphur dioxide is formed when coal containing sulphur is burned in power stations – this can be removed within the power station before being released into the atmosphere
Nitrogen oxides are formed when petrol burns in vehicle engines – this can be converted into harmless gases using a catalytic converter

15. “Acid rain does not affect global warming”
Explain why the following statement is not entirely true…
“Acid rain does not affect global warming”
Think about what happens when the acid dissolves rocks (what is released etc…) and how destroying plants may increase the rate of global warming…
Acid rain can dissolve rocks which release carbon dioxide (a greenhouse gas)
Acid rain also increase soli acidity, inhibiting plant growth (which usually absorb CO2)