Summer SAVY 2016 (Session 3, Day 3) – Chemical Spill
Today we continued studying Chemical Spills!, this time focusing our attention on the Flint, MI water crisis. We learned that toxic metals, specifically lead, had leached from the pipes that provide water to the city. We then discussed the idea of heavy metals and the fact that some of these metals are actually beneficial to us in small amounts but toxic in higher concentrations. The students were quick to point out that we need certain heavy metals like iron, even to the point that they are added to foods like cereal! We discussed the detrimental effects of lead in human health and how lead can be removed, both from the body in a medical sense via chelation and from water sources via precipitation (among other techniques). Finally, since the Flint water appeared to have more than just lead in it (since Flint’s water was colored and opaque and lead in solution is clear), we discussed the process of water treatment. The students then created filters out of a variety of materials to filter dirty water and then tried their filters on a solution of silver ions that they precipitated using a solution of potassium iodide. Ask your student which materials worked best in their filter, especially since we built several different ones since the students were eager to improve their filters if at first they proved ineffective.
In the afternoon, we learned about how scientists could test the effects of toxic metals on bacteria to estimate their approximate relative toxicities. We analyzed some example results, developing our experimental design vocabulary in the process, and determined which metals are, in general, more toxic than others. We concluded by reading an article describing the Flint water crisis in detail, including the people involved and the mistakes that were made in the process. Students were then encouraged to either develop a plan to get clean water to the residents or write a public service announcement describing the situation and the potential health consequences of lead-containing water. Consider discussing with your student his/her proposed solution and whom they think should be held responsible for the crisis.
I’m looking forward to tomorrow when we will discuss oil spills!