For Budding Citizen Scientists and Their Parents:
Testing the Water in the Otonabee With Water Ranger Luke

testing for oxygen

PATRICIA REMY – Have you been there? I visited McBride Island, just north of the zoo in Riverview Park, Peterborough. Water Ranger Luke had invited me to do a real, live outdoor experiment.

Luke Williamson, who grew up in Peterborough, has now, with others, developed an easy-to use-kit to keep tabs on the health of our local lakes, streams and rivers. It’s the Water Rangers’ Education Test Kit Field Guide. The Greenzine reported on the kit a couple of weeks ago. Now I was about to see it in action.

First, we noted the weather, hazy but warm, and hung a thermometer in a nearby tree. Then we clambered down to some flat rocks at the edge of the Otonabee. Luke took a plastic cup from the kit and dipped up some river water.

Luke collects water
test strips
temperature, hardness

We used strips of paper which change colour when they are dipped into the water. This way you can test for how much chlorine is in the water. Chlorine is a poisonous gas. It is used on the Otonabee water before we drink it at the plant where the water is treated. Just enough chlorine kills the germs in the water. Too much would be harmful. It would burn your throat and the inside of your nose and mouth. There are other towns besides Peterborough on the Otonabee River. They treat their water, too. The water which arrives in Peterborough, though, does not have too much chlorine. It can be treated again to make really sure that the bad germs are gone. How do I know? We tested it!

When water flows over rocks, especially limestone, which looks a bit like really hard chalk, it dissolves tiny bits of the rocks just like sugar dissolves in tea. When there is too much chalky stuff in the water, we say it is hard. When you have a shower you feel some sticky stuff in your hair. It makes a ring on the bathtub. Some people have water-softeners in their houses to take the bits of chalk (much too small for you to see) out of the water.

There is also something called pH. It goes from 1 to 14. Most of you have heard of acids. Acids have a low pH. A strong acid has a pH of 1. You would not want to put your fingers into that! Strong acid can chew up your flesh and take the skin off your bones. A really high pH is just as dangerous as a low pH. We call it alkaline. Acid and alkaline are opposites, but strong acids and strong alkalis are equally dangerous. Pure water has a pH of 7. Rain water has a pH of 5.5. I am sure you have heard of carbon dioxide, a gas in the air. When air mixes with the water of lakes and streams, for instance when it rains or the water splashes over rocks, it takes in some carbon dioxide and becomes a weak acid. If there is a lot of smoke in the air, for example from factories or forest fires, the water in lakes and rivers can turn into a stronger acid, have a smaller pH. When the pH gets below 5, the water starts to hurt frogs, fish, and clams. They die. The shells of the eggs of water birds get weak. The chicks suffer. So pH is important!

Everything we measured showed us that the Otonabee water off McBride Island is safe. Or to be very scientific, it was, at the time we tested it, safe. (You could swim in it without getting sick, but swimming is not allowed for other reasons. The current in the river off Riverview Park is too dangerous.)

We also tested for how much oxygen there is in the water. You have probably heard of oxygen, too. It is the part of the air we breathe, which keeps us alive. Fish need oxygen to breathe, just as much as we do. They take it out of the water with their gills. Here’s the thing, though. If the water gets too warm, oxygen bubbles out of it and there is too little for the fish to breathe. If you see a fish sticking its snout out of the water and gasping for breath, it is because there is no longer enough oxygen in the water. Warm water is nice for swimming, but when it gets warmer than 32°C. or 90°F., fish can’t breathe anymore. When the water is that warm, we don’t even like it for swimming. On the day Luke and I tested the water, it was around 18°C., a bit chilly for me, but just right for the fish. What will happen to the water, if we have a long, really hot summer?

A real scientist would test the water every month or so, to keep track of changes which might happen. In the Guide Book there are instructions on how to enter what you found out online and see what Water Rangers in Europe and other parts of the world have measured. Follow the links at

kit comes in a small backpack

A note to parents: the Water Ranger Test Kit is in use at Cobourg Collegiate. However, much younger children can understand what it is all about, if an adult explains it to them. You can find it online by searching for it at or by sending an e-mail to Maybe something to recommend for summer camp? Or an extended family weekend at the cottage?

Luke Williamson lived in Peterborough for more than 20 years. He graduated recently from the University of Ottawa with a B.Ed. He is the store manager and coordinator for the Water Rangers’ Test Kit.

For Budding Citizen Scientists and Their Parents: Testing the Water in the Otonabee With Water Ranger Luke © 2022 by Patricia Remy in The Greenzine is licensed under CC BY-NC-ND 4.0 

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