Last year I did almost the same experiment. but here we are doing a modified version. I put two students per bag in the window, and two of each of two types of seeds. Each student folded and placed in a paper towel, and I ran a line of 6 staples to hold the seeds up and away from the water at the bottom.
We're doing this so students can actually OBSERVE the roots and shoots as a plants begins to grow. Looking at a poster in FINE, but I'd much rather see it for REAL, wouldn't you?