Share it! Science : Science Teacher's Toolbox: Testing Water Quality

Monday, June 8, 2015

Science Teacher's Toolbox: Testing Water Quality


It's World Oceans Day! Even if you don't find yourself near an ocean today, you certainly can appreciate water and its importance. Let's take a closer look at how you can get kids involved in some real science where water is concerned. 

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Water Quality
Testing water quality is a great way to engage students in collecting data and contributing to science at a local and global level. This type of project is certainly not just for school, it could be done at home, in an environmental club, summer camp, etc.

It is easy to get involved in a global water quality testing project through the World Water Monitoring Challenge.  This is an international citizen science project where groups and individuals complete basic water quality tests on local bodies of water and contribute their findings online. Test kits are reasonably priced and can be ordered through Lamotte here.  

If you do not have experience testing pH, dissolved oxygen, turbidity or temperature of water I would highly recommend these easy to use kits and resources! As this program has grown they have included many educational resources. You can find lesson plans that were developed especially for this project here.

I have used these kits as an introduction to water quality with my students in our classroom aquarium and then outside in a local stream and some human-made ponds. The kids enjoy doing the tests and really take ownership over their data collection as they know they are reporting it to the World Water Monitoring Challenge.




If you are a teacher developing an entire unit around water quality or just want to dive deeper into understanding the topic, you'll want to spend some more time investigating pH, learning where our drinking water comes from and maybe even collecting macroinvertebrates to gauge ecosystem health!


Testing pH
pH is a fun chemistry topic to study with upper elementary through high school age students. At least once a year I get out the red cabbage to create a pH indicator solution with my students. We test all sorts of household liquids for acidity and basicity.  

Cabbage contains pigments that work as indicators of pH. Some people boil the cabbage, but I've found that tearing some up and putting it in a blender with some water does the trick. I've also had kids grind the cabbage leaves with some water in a mortar and pestle, which they think is fun. With some clear cups and eye droppers or pipettes you can test the pH all sorts of solutions. I avoid anything too harsh, but there are many things right in the kitchen that work well- dish soap, baking soda water, salt water, vinegar, different juices, etc. For a great summary of pH and a few different ways to test it, check out this great post on Growing with Science. You can also make your own pH paper out of red poinsettia leaves if you are trying this around the holiday season. Learn how in my post, "Science with Christmas Leftovers".

You can use pH paper, or litmus paper, to test the pH of liquids and if you wish to go high-tech there are meters and probes you can purchase fairly inexpensively by clicking the links or checking out the Amazon widget below. There are many ways to do a pH experiment, most likely you have what you need right at home!

Drinking Water
Depending on the age group of the children you are working with and their prior knowledge you might want to investigate where your drinking water comes from. It could be a reservoir or well, or maybe even spring fed! If you cannot visit a water treatment plant, you can at least show students the process. I use this short clip from PBS LearningMedia's collection. It is from an episode of Zoom where they visit a water treatment plant.

Collecting Macroinvertebrates
One of the most exciting water quality activities to do is to collect and identify macroinvertebrates. These are the sensitive insects, larvae, worms, etc. that live in wetlands and waterways. Depending on what you find, you can determine the health of the water. 

You don't need any high tech equipment to do this. Find a vernal pool, stream, pond, etc. and bring along a kitchen sieve, a spoon and a small paintbrush. Remember- these creatures can be sensitive and fragile, or water predators with pincers, so you don't want to grab them with your fingers! If you fill a basin with some of the water from the area you'll have a place to observe what you find. Scoop up water, leaf litter and debris with the sieve. Very carefully look through the litter to find these tiny creatures. Lightly brush them onto your spoon and dip the spoon into the water in the basin. What have you found? 
Dragonfly Nymph [image: Totodu74 [Public domain], via Wikimedia Commons]

To help you determine what you've collected and what it means download an identification key. These creatures are organized into three groups based on their tolerance to pollution. You can find charts to help you determine which group your species are in.

Here are some good examples:

Citizen Science
Water quality is a great way to get involved in citizen science and local environmental monitoring. Whether you try the World Water Monitoring Challenge kits or find another local project it is an excellent way to get kids involved in an authentic science project. Check out these links to find water citizen science and volunteer projects near you:
Suggested Supplies for Testing Water Quality:
Resources:


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