Our Eco Challenge in Primary 3 was to design the garden beside the dinner hall door. We measured the area then came back to class to draw our design of what we thought would work well in the area. We have also been trying hard to reduce the amount of paper in our blue bag. We have even given someone a job in class to check that the paper in the bag has been used on both sides before it goes in!
I like your idea of checking that paper has been used on both sides P3. I think we should encourage all classes to have a paper monitor.