I used this notebook insert to explain these 4 cycles (water, carbon, oxygen and nitrogen). You can use this as a lecture aid, research study, etc. Have them use 4 different colors for the arrows and then cut it out and glue into their notebook. You could also just use it as a worksheet after you lecture. I left space for your specific directions at the top. I added that I wanted my students to make one picture showing all 4 cycles. I included 2 student examples of that and a teacher key. Feel free, of course, to add to the cycles and make them more detailed. I also included the key to another lesson I have posted on "biogeochemical cycle drawing" which is basically the same drawing. It is in color on the other lesson.