'Forest In a Jar', an AskERIC Lesson Plan:
    http://ericir.syr.edu/Virtual/Lessons/Science/Ecology/ECL0028.html

'Conserving Electricity: Turn It Off':
    http://www.tnrcc.state.tx.us/air/monops/lessons/turnitofflesson.html

'Objects in Nature':
    http://www.lessonplanspage.com/printables/PLANature.htm