I have been loving all the Earth Day materials floating around. I know for me, many of my students have a difficult time making connections and categorizing. I created a coloring activity to work on this. You can use this along with all the sorting activities already out there. You can discuss these items in terms of: “What are they used for?” and “What are they made out of?”
I just love those simple print and go activities to be used as review or homework. If you don't have the luxury of printing in color for all of your students, you can print in black-and-white and then use a highlighter to demonstrate which colors should be used for which types of items.
I also created some sorting cards to use as a memory game or introduction of the concept activity.