Acid rain powerpoint and literacy task

Powerpoint I used with LA yr 8 on acid rain at the end of the Earth and Atmosphere task. It is very basic but covers the main science behind it. There are 3 worksheets in the middle differentiated for literacy ability that I gave to certain students in different ability groups. There is a literacy task at the end (my pupils' literacy levels are very low) for them to write a short letter using the knowledge they have learned.