by Stacey Johnson, Oklea Middle School
When you think of drinking water….oh wait, most of us do not think too much while drinking water; we simply relish in its ability to quench our thirst and give our body the hydration it needs to survive. After attending the OSTA conference session titled “Water like Wine” you would never be able to drink another glass of water again without wondering what chemicals invisibly lie below the surface.
The ability for a citizen of Oregon to critically look at their own water supply is more important now than it ever was in the past. With the abundance of lead fixtures in old schools and buildings as well as the slowly dwindling supply of clean potable water, our students need to be literate in water quality analysis. This endeavor is what drew me to attend this session.
We started with working through the chemistry of the water we had on our table. We started with a quick conductivity test for dissolved solids and then Jan Migaki taught us tips and tricks for doing fast qualitative analysis of water quality through bubble production and the use of lettuce seeds as a bioindicator. I already complete a water quality unit with my students using vernier probeware and Hach kits, but was missing other qualitative measures of water quality to draw in every level of student. While probes and kits are great at acquiring quantitative data, you forget that using numbers to assess the state of a waterway can sometimes lead to slow processing of what the numbers ultimately mean. Lettuce seeds are a cheap source of seeds, they germinate quickly and are a useful bioindicator of water quality. Think “canary in the mine” but for waterways. You can count the number of lettuce sprout fronds, length of root and color of leaves as an indicator of sprout health. When you shake a bottle of water you can indirectly measure the amount of dissolved solids by the amount of foam when a soap is introduced. More bubbles means less dissolved solids and lower conductivity. The use of seeds also allows you to open up the conversation and connect water chemistry to the ecosystem as a whole and how water chemistry can affect the living creatures within the water.
Another novel idea is letting the students create their own water filtration systems using a 20oz water bottle cut in half and the top half flipped over. You can place food coloring or smells in the dirty water and the students could attempt to remove those small particulates, only to realize that they are difficult to near impossible to remove. The students can then equate this with their municipal water treatment and assess the effectiveness of their local systems. A really cool hint was the use of Alum, it will flocculate the suspended solids and then settle them to the bottom. This was a technique I was not aware of and will incorporate into future lessons on filtration. Also, flocculate is a really fun word!
Students love getting wet, we all need to drink water and there are so many local connections you can make no matter your locale. This form of a unit is a great way to incorporate many different areas and standards. Jan, the session presenter, is both very knowledgeable and enthusiastic about the topic. Now it is time to get our kids excited and concerned about water!