Water samples from local ponds, lakes, and puddles
Have the students bring in water samples approximately a week before the experiment. Add a few blades of grass or hay to each sample and let it sit for a week.
Have the students create slides using the water sample that they brought in. No dye is necessary; simply place a slide cover over a drop of water. The tension of the water should hold the slide flat. After a week, there should be a large number of organisms present. Before performing this experiment, it might be a good idea to pick up a microbiology book to get an idea what type of organisms might be present. Paramecium, flagellum, and rotifers were present in my samples, but many others may show up! The students were mesmerized with this one. I have never seen students so interested in science!
Shawn Len, 2000.