The Effects of Acid Rain - Activity - TeachEngineering 3 small cups labeled with group names (clear plastic cups work best) 3 nails (or other sharp objects that could scratch chalk) 3 strips litmus paper Acid Rain Worksheet, one per student Acid KWL Chart, one per student For the teacher/instructor: waterproof marker timer, such as a watch, clock or stopwatch Worksheets and Attachments