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Examining the health of a local waterway
Examining the health of a local waterway
Study/Challenge: to examine the health of a local waterway by collecting macro-invertebrates and determining the EPT index (percentage of macro-invertebrates that can survive only in unpolluted water).
Materials:
- buckets and nets to collect stream samples
- white tubs
- hand lenses or magnifying glasses
- petri dishes, pipettes, and tweezers
- optional - hip waders
Safety Notes: If using this activity with younger students or unable to provide transportation of students to stream site, the samples can be collected by the teacher and brought to class for examination. A good way to collect the samples is to find a shallow running stream in the spring when the insects are returning (May and June). You are looking for their larvae which lives in the stream in its infant stage of development. What I did was put on some rubber boots, take a large fine net (there are nets available for stream sampling which we have), put it in the water and kick around the rocks and silt on the bottom of the stream to loosen up anything living in there. I emptied the net and did this a few times into a pail of stream water that was about half full. I did this for two pails and then brought it to class the next day.
If students are collecting the stream samples, appropriate safety precautions must be put in place. Ask your administration how to do this activity safely according to their guidelines.
Lesson Plan:
Lesson Plan:
1. Set the stage. Activate prior knowledge by asking students questions like:
- Have you ever seen a stream before? What can you remember about it?
- Show pictures of streams on your smartboard or other visual device. What kind of living things are in streams? Where do steams go? Trace the path of rivers to lakes or other rivers that lead eventually to the ocean.
- What would happen if pollution went into streams? What kind of pollution can go into streams?
- Discuss macro-invertebrates using the attached slideshow*** and use the additional resources section to extend their understanding of the upcoming activity.
2. Prepare for and conduct the stream sample.
a) Collect the necessary items - petri dishes, pipettes, magnifying glasses or hand lenses, tweezers, scoop or small dish to use as a scoop, white dishes, tracking sheet for macroinvertebrates - use Tracking sheet for Macro-invertebrates or other similar tracking sheet
b) Have students work in pairs to collect the data for the study. One student can sort through the water and find the macro-invertebrates, and the other can tally the findings. They can switch halfway to allow both students to experience the different jobs.
c) Students will take a sample from one of the pails by scooping some into the white dish. Using a white dish helps students see if there is movement or see any animals swimming around. They can use the pipettes to suck up the smaller animals and use petri dishes to separate them into different kinds of macroinvertebrates or other animals. The larger animals may need to be separated with tweezers. SAFETY PRECAUTION: Remind students to not use their fingers to touch the animals but to be respectful when moving them. Some of the macro-invertebrates or animals may have pincers.
d) Students continue to tally the macro-invertebrates that they find until they seem to be finished. They can examine the animals they find using the hand lenses. If you have access to dissecting microscopes, you can see the animals even closer!
e) Conduct a classroom tally by having each group share their results on a google doc, Smart Notebook, a chart paper tally sheet, or on a whiteboard tally sheet. Students then take the class data and calculate the percentage of the inhabitants of the stream (students may need to be guided through this calculation if percentage has not been reviewed yet with the class).
f) Use the class data to complete an EPT index calculation with the class - this can be guided or left for the students to figure out in their paired groups.
g) Discuss the importance of their findings. What should they do with this important data? Should more than one sample of the stream be collected to see if their findings are accurate? What are any sources of experimental error in this collection? If the EPT index is low or high, what does that mean?
Extensions:
- Language/Science: Allow students the opportunity to conduct some self-guided research on topics related to stream pollution, water pollution, water treatment plants, stream ecosystems, animals sensitive to pollution, macro-invertebrates and their role in ecosystems, etc. They can present their findings individually, in pairs, or in groups and choose from a variety of presentation media such as Google slides, Prezi, I movie, posters, pamphlets, news articles, or other presentation forms.
Overall Assessment can include Language (for the Extension activity), Science Expectations and Math Expectations:
- Reading: 1.2, 1.4, 1.6, 1.7, 1.8
- Writing: 1.3, 1.4, 1.5, 1.6, 2.1, 2.7, 2.8
- Media: 3.2, 3.4
- Oral and Visual Communication: 2.1, 2.3, 2.4, 2.7
- Science - Biodiversity Expectations: 1.1, 2.1, 2.2, 2.3, 2.5, 3.1
- Math - percentage calculation and understanding of relationships involving percentages; read, interpret, and draw conclusions from primary data; collect data by conducting an experiment to do with their environment, and record observations or measurements; solve problems using multiplication and division using a variety of strategies; make connections among mathematical concepts and procedures, and relate mathematical ideas to situations drawn from other contexts; develop, select, and apply problem-solving strategies as they pose and solve problems and conduct investigations, to help deepen their mathematical understanding; develop and apply reasoning skills to make and investigate conjectures and construct and defend arguments; communicate mathematical thinking orally, visually, and in writing, using everyday language
***Special thanks to Opeongo High School teacher Mr. Tim Demmons and his Osprey team for assisting us with our first stream study and sharing the above slide show with us!
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