Acid rain.

Videos:

Introduction: http://www.youtube.com/watch?v=yphLO8S77MY&feature=related

Acid rain eating Washington: http://www.youtube.com/watch?v=MqHw1hMEkAQ

Causes and effect of acid rain: http://www.youtube.com/watch?v=893KB3s_jIA&feature=related

 

EPA: http://www.epa.gov/acidrain/education/site_kids/

Sheets: http://www.ace.mmu.ac.uk/kids/acidrain.html

Power Point: http://science.pppst.com/acidrain.html