Background: We had field tripped to upper Santa Ynez River , tested for several water quality factors (some in field, some w/ samples back at lab). Kids did regular reports on their findings. This activity took about 4 periods (43 min), although it was built on other kinds of work we'd done with topo maps, soil drainage, groundwater in general. I had used "The Fruitvale Story" in the past with pretty good success, so I used the kids-do-investigation storyline to try to put together some skills this group of kids were working on.
The data table includes the data they had already really recorded from upriver, lake, and under freeway at Buellton. The remaining river sample and the choices of well test sites were all just different pH samples so that the appropriate color range would demonstrate concentrations of pollutant.
First we looked on the internet for info that might tell us what the probable contaminant was. I had previously scouted some sites, which in fact gave me the Blue Baby idea, which proved to be a very good hook for 7th graders, better than diarreaha! Discussions led all classes to feel pretty sure that it was some kind of oxygen problem.
I actually had already printed out the info on various contaminants, and had the addreseses in my disk cache so that "browsing" was directed and much quicker than a real search. Groups got copies of all the pages, split up responsibilities to search for clues in whatever way they wanted. Most just took one or two things, like lead & coliforms, to read, and with minimum coaching they used scanning for keywords to help them. It was pretty high level/unfamiliar vocabulary for them, but they did great. (I see why SB and Lompoc are doing so well with Mystery type activities.)
It took about a whole period for them to all agree that it must be nitrates (one sentence actually said "blue babies"). Then each group wrote their first for test sites from a closeup map.....I drew numbered circles and a key for them using a paint program on a scanned AAA map......you could just draw one up by hand too.
They had to write a short justification for choices, like "it's just downriver from the golf course", or "it's up the hill from where three of the sick babies houses are" before they could get their test drops and indicator bottles.
They color coded each well based on result, then tried to draw reasonable contamination plumes on transparencies of the map. Each group got up in front,displayed map, gave their idea for possible pollution source (I set it up that it was most likely the factory up the hill on the south side). Finally, they had to write/tell what they would do next......i.e. tell the city what they found, investigate what the factory did, etc.
We have data posted on our BBS for the three real test sites, if anyone else tests points on a river they could post too. With that as a starting point, the blend of real/simulated is pretty easy to do to suit your particular purposes. The kids knew the 20+ possible "test well" sample were just various concentrations of acids or bases, good review for them.
URL's for water quality info online: back to Tapwater Overview