Think of ideas....

Since a big part of the SCOS for early grades focuses on patterns, sorting, and comparing I think a fun lesson would be to make a class book about leaves and trees. As a class you could go outside and let everyone find a leaf of their choosing. They would need to make a drawing of it and (with either teacher or parental help) identify the type of tree it came from. The class culd make a bullitan board by arranging thier actual leaves (that have been laminated and cut into squares) in a pattern and let the other classes guess at what rules they had used that led them to arrange such a pattern. All the drawings and sketchings they made of their leaves, as well as a few fun facts about the tree it came from, could be put together to make a class encyclopedia. 

A messy lesson plan I found online that I thought would be enlightening was making your own landfill. Though it's a project that is done over quite a while (6 weeks) if you left it over December break (or had jars that you had started weeks before), it could be done. I think that not only would All About Trash be fun and interesting to watch, but seeing the exact process of what happens after we throw the trash out may give students an understanding about why recyling is important. 

All About Trash by Dawn Gilbert

http://www.learnnc.org/lp/pages/3637

*Image credit http://farm1.static.flickr.com/31/61114776_66062dcac8.jpg?v=0