Like most students, kids studied a chart of microinvertebrates.
But unlike many, they got to pull on hip wader boots, grab nets and dredge the Chicago River bottom to see the critters up close, learning about river water ecology along the way.
Cathy Murges, an Emerson seventh grade teacher, arranged for the students to take a bus Tuesday to the Linne Woods forest preserve in Morton Grove, where Mark Hauser, education manager of Friends of the Chicago River, briefed them.
"You're going to know you have something if something is wiggling in your net," he advised.
Then the students pulled on rubber boots up to their hips, walked down to the river bank, stepped in and dragged their nets along the bottom, as Hauser had showed them.
They spent about an hour scooping up water and examining it for signs of life. Often, cries of excitement went up as students found a scud, beetle or larva, and then deposited it in one of several white pans of water Hauser set up so all the students could get a good look at the invertebrates.
When one student made an exciting find, Hauser proudly announced to the kids, "This is the king of the river--a dragonfly larva." He explained it would turn into a dragonfly just as a caterpillar turns into a butterfly. Dragonfly larva can only survive in fairly clean water, which indicates the health of the river, according to Murges.
The total take? The students found 11 species of benthic (bottom-dwelling) microinvertebrates. Three other classes did the same field trip, and Murges will add up the totals of what they found.
Friends of the Chicago River conducts these outings as part of its Chicago River Schools network, Hauser said.
"The goal is s simply to bring kids close to nature and let them explore, and secondarily to do the science part" he said.