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No3 to Nitrate in Our Waterways

Grades: 9-12 Biology, Chemistry, Environmental Science, Earth Science, Scientific Ways of Knowing and Scientific Inquiry
Author: Erika Smeader
Source: Original - This material is based upon work supported by the National Science Foundation under Grant No. EEC- 1542358.


Students will analyze water samples with a portable spectrometer for phosphate and nitrate levels in water sources. They will then apply this knowledge to understanding how monitoring these levels can be used on a global level to analyze and monitor water quality.


What should students know as a result of this lesson?

Students will be able to identify:

  • Students should comprehend the nutrient cycles, specifically water, phosphate, and nitrogen
  • Students should comprehend the causes of algal blooms in aquatic ecosystems
  • Students should understand basic spectrometry

What should the students be able to do as a result of this lesson?

Students will be able to do the following:

  • Students should be able to research effects of fertilizer and agriculture on aquatic ecosystems
  • Students should be able to research global water concerns
  • Students should be able to hypothesize on environmental implications that a affordable and portable spectrometer could bring to analyzing local water sources
  • Students will run experiment using portable spectrometer to analyze water samples


  • Computers
  • App on phone (at least the teacher should have this)
  • Googles
  • Gloves
  • Field Spectrometer
  • API Nitrate reagent kit (sold at pet stores or online)
  • Water samples (collect from area water sources) make sure you have enough water for every student station to run a trial. The amount will depend on how many students are in a class. Students can collect to be more actively involved in experiment.
  • Diluted nitrate solution to create a positive sample
  • Stopwatch
  • Pipettes

*******Field spectrometers and phone app are not currently available on the market. You can email either,, or to order a spectrometer. You can modify this lab by just using API nitrate reagent if spectrometer is not available.



Class 1: Engaging prior knowledge as investigating current issues to set a foundation for use of portable spectrometer and important uses today.

Use student worksheet 1 to lead discussion. After each section stop to discuss answers as a class. Discussion questions centered around global water crisis, definition of eutrophication, exploration of causes of algal blooms, researching area waterways, and discovering what citizen science can do for an area.

(This worksheet is adjusted to local waterways. Depending on where you live you might need to visit the EPA website and change the worksheet to your local waterways.)


Class 2: Use portable API nitrate solution and possibly spectrometer to analyze water samples from the area for nitrate levels. The students will then answer will then answer analysis of data questions.


Instructions on how to prepare samples:

  • Sample 1 (control)
    1. Add 2 mL of water sample to container 1 and cap
  • Sample 2 (water and reagent)
    1. Add 2 mL of water sample to container 2
    2. Add 2 drops of Nitrate Test Solution (#1 marked bottle) to container
    3. Cap and invert container for 30 sec
    4. Pick up Nitrate Test Solution (#2) and vigorously shake the bottle for 10 sec
    5. Add to container 2- 2 drops of Nitrate Test Solution (#2)
    6. Cap container 2 and shake vigorously for 1 minute ******very important step/if done incorrectly then results may not be accurate
    7. Put sample down and wait 5 minutes for color to develop
    8. Use color strip to read results.
    9. Document results in data table below.

If spectrometer and app for phone are available you can complete this section of the activity:

Instructions on how to use spectrometer:

  1. Turn spectrometer on by switching button to on position on the bottom of the machine.
  2. Take control sample(previously made) and pour into container one for spectrometer and place cap on top. Place control in position one of spectrometer.
  3. Take sample with reagent and pour into container 2 of spectrometer and place cap on top. Place into position 2 of spectrometer.
  4. Turn phone on and open camera.
  5. Place lens of camera over opening where the prism is present. You will see the prism on your phone screen. If you do not keep moving phone until you see the image.
  6. You should see two distinct rainbows on your camera or you have not placed your phone correctly.
  7. Take a picture/save picture if needed/close camera
  8. Open App on phone/upload picture/read results of sample.
  9. Document results in data table below.

Students will also investigate 3 unknown sample to see if any test positive for nitrate.

Make three unknown samples (enough for the amount of students you have) they will use 2 ml per sample and make one of the three samples with nitrate solution in it so that is test positive. The other two samples should be regular tap so they do not test positive. Keep track of the sample number you chose to be positive. You can make more than one sample positive if you want, but make sure at least one sample is positive. Do not make all three positive.


Students will answer analysis and discussion questions on class activity sheet on how the field spectrometer is used and how it can be useful in real world situations. The answers will be discussed as a class.


Class 3: Read the article located from the link given on polymer filters and global water crisis. Students should then write a short paragraph on how the filters work and possible implications for solving non-drinkable water problem.


  • Students should have an understanding of the nitrogen/water/phosphate cycle.
  • Students should have an understanding of how an ecosystem works.

Best Teaching Practices

  • Questioning
  • Hands-On/Minds-On Learning
  • Inquiry Approaches
  • Real-life Situations and Problem Solving

Alignment with Standards

NGSS Standards:

  • HS-LS2-6. Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem.

Ohio Standards:

  • Science Inquiry and Application: Identify questions and concepts that guide scientific investigations; Design and conduct scientific investigations; Use technology and mathematics to improve investigations and communications; Formulate and revise explanations and models using logic and evidence (critical thinking); Recognize and analyze explanations and models; and Communicate and support a scientific argument.

Content Knowledge

  • Students will use computers to investigate websites to research and answer discussion questions
  • Nitrogen/phosphate/water cycle
  • Basic spectrometry


  • Goggles
  • Gloves


Content is applied in the real world as understanding that this device helps connect people with a device that analyzes nitrate and phosphate levels in aquatic ecosystems. This information further helps people monitor.


Student assessment is involved in all three of the class activities.

Other Considerations

Grouping Suggestions:

  • Students should be grouped as lab table, with 3 to 4 students per group.

Pacing/Suggested Time:

  • N/A

Printable PDF Worksheets

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