Water Quality Testing in your Local Water Cycle
This activity is designed to get students thinking about where they find water in their local environment, where that water came from, and what part of the water cycle that water represents. Students identify a number of sources of water that are available to them locally. They collect samples of that water to bring back to class and perform simple chemical tests including pH, Hardness, Phosphates, Alkalinity, Nitrates and Nitrites. Water samples can also be analyzed for microscopic (and macroscopic) biology. Prior to completing the chemical analyses, students are asked to describe the water visually and decide whether or not they would drink it and why/why not.
Learn more about the course for which this activity was developed.
- Students recognize the many places where they can find water in their local community.
- Students learn about where different waters come from and how they fit into the water cycle.
- Students are able to make connections between different water samples, for example rain water that fell in the bluffs flows through a small stream before entering the Mississippi River.
- Students perform simple chemical analyses and examine the biology that exists in different water samples.
Context for Use
Description and Teaching Materials
- Students are first asked to identify different samples of water that they have access to in their local environment and link those samples to their position in the water cycle. Samples typically include water from local rivers and streams, rain water, well water (softened and unsoftened), city water, bottled water, lake water, etc. Samples are collected by the students and brought to class.
- To add a bit of experiment design and "real science" students are then told that they only have the funds to analyze 8 out of the 10 samples that they have collected (or however the numbers work out). Students then decide among themselves what questions they want to focus on for their study and which samples will best help them answer those questions. Students are typically very interested in studying the water samples that they drink (city water, bottled water, well water) or water they interact with (water from the local swimming lake, the river they fish in). Another good study is to follow how the water chemistry changes as a sample moves through the water cycle or through the Earth.
- Students investigate the different types of water tests that they will perform and they teach each other about their findings, especially regarding what levels of each test are fit for human consumption and where the different chemicals come from. Students make predictions about which samples they think will have the most/least of the chemicals and why. They also predict whether the water sample is drinkable and identify which samples they would drink.
- Tests are performed using simple water quality test strips from Hach Company (www.hach.com). In particular, we use the 5 in 1 test strips that test pH, Hardness, Alkalinity, and Chlorine, and the test strips for Nitrates/Nitrites and Phosphates. Students perform these tests and collect data in class.
- Students then analyze the data and compare their findings to their predictions. Results are discussed in class and a reflective essay and lesson plan is created by the students. These results are used on the field trip and are assessed as part of their final field trip report.
Teaching Notes and Tips
Students are assessed on their water testing results as part of their final field trip report.
Rubric for assessing metacognitive reflections (Acrobat (PDF) 146kB May7 07)