Standards Aligned

Science

• MS-LS2-1. Analyze and interpret data to provided evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem.
• MS-ESS2-2. Construct an explanation based on evidence for how geoscience processes have changed Earth’s surface at varying time and spatial scales.
• MS-ESS2-4. Develop a model to describe the cycling of water through Earth’s systems driven by energy from the sun and the force of gravity.
• MS-ESS3-1. Construct a scientific explanation based on evidence for how the uneven distributions of Earth’s mineral, energy, and groundwater resources are the result of past and current geoscience processes.

English

• W.7.1. Write arguments to support claims with clear reasons and relevant evidence.
• W.7.10. Demonstrate command of the conventions of Standard English grammar and usage when writing.
• W.8.1. Write arguments to support claims with clear reasons and relevant evidence.

Learning Objectives

• Students will construct a scientific explanation, based on evidence, for how the uneven distributions of groundwater resources are the result of past and current geoscience processes.
• Students will analyze data on how management practices can impact the quality of surrounding groundwater.
• Students will plan and conduct an investigation of the properties of water and its effect on Earth’s materials and surface processes.
• Students will research ways farmers are protecting water supplies by controlling the amount of soil runoff.

Materials

• Water Quality PowerPoint
•  6 canning jars for storage of water samples (1 jar per lab group)
• Water samples from different sources (you can obtain samples from a local lake, pond, park, faucet, etc.)
• Total dissolved solids, temperature, and electrical conductivity meter (1 kit per group) (link to order)
• Leaf Luster testing kit (1 kit per group) (link to order)

Procedures for Instruction

Length of Time for Preparation: 1 day
Gather your materials for each lab group. Obtain a water sample for each lab group. You can either have them test the same water sample to check for accuracy or you can have each lab group test a different sample and share their results with the class.

Length of Time for Classroom Teaching: 1-2 days

• Day 1: Students perform lab through observations, record data and comparisons.
• Day 2: Lab review and report.

Background Information

For this lab, we will test water supplies from various locations looking for key deficiencies or overabundance for potassium, phosphorus, nitrogen, pH, total dissolved solids and electrical conductivity.
Electrical conductivity (EC) will show the presence of salts in the water. The higher the salt content, the higher the conductivity reading. An EC test can provide results indicating growth damage due to nutrient deficiencies and lower water uptake by the crop.
Total dissolved solids (TDS) is a measure of all the dissolved substances in water. This is usually closely related to EC levels and has the same plant growth problems as EC.

Potassium is important for the strength of the plant. It helps to promote protein synthesis inside the plant. High levels of potassium in water may indicate contamination from fertilizer runoff.
Phosphorus plays a major role in plant genetics and seed development. Elevated levels in water indicates fertilizer runoff and can also deter other nutrients from functioning properly.

Nitrogen is directly responsible for leaf production and color. The presence in water for irrigation can be beneficial but must be regulated into the fertilizer program for the crop. Fertilizer runoff is the main source of nitrogen in the water and can be a concern for both human and animal consumption.

pH measures the acidity and alkalinity of water. The correct pH is vital to the growth of plants as it controls the utilization of nutrients. pH levels that are too high can cause serious deficiencies in vital nutrients needed for optimal growth and development.

Farmers and ranchers work hard to ensure they have a successful crop by reducing potential pollutants and decreasing the availability of

• soil to become sediment, primarily through the use of agronomic practices, such as cover crops, residue management, and rotations that include close-grown crops;
• nutrients for transport, by accounting for all nutrients available, regardless of source, method of incorporation, and application rate and timing; and
• pesticides through integrated pest management, including crop rotations, cultivation, biological pest control, scouting, and selecting pesticides that are more environmentally friendly as well as through reducing the use of pesticides in their operations.

Classroom Discussion

Pre-lab Questions
Introduce the topic and assess students for prior understanding. Let students discuss their ideas, and guide the discussion without telling them if they are right or wrong.
Our job is to investigate the water quality of the source of water collected.

• Why is the quality of water important?
• What do you do to preserve good water quality?
• How about your community? What practices are used to preserve water quality?
• Why would farmers improve their management practices to preserve water?
  • Note that farmers not only want to preserve water quality, but they want to keep the fertilizer and pesticides that they apply to the field on their field as it cost a lot of money to apply. Also, farmers are regulated and have to watch their management practices to preserve our water quality and environment.

Procedure for Lab

Station Setup

1. Gather water samples from various sources. Label each source for accuracy. You can call a local farmer or rancher to have access to a water source, if needed.
2. You can have each lab test a different source and report to the rest of the class their findings or have every group test the same sources for accuracy.

Perform the Lab

1. Take the lid off of your first sample.
2. Turn on the TDS/EC/TEMP meter and put the probe side of the meter into the sample. When the ppm unit starts flashing, push the on/off button once. This will hold the reading on the screen. Record your TDS reading in your lab book.
3. Push the mode button once to switch to the EC reading. Record this number in your lab book.
4. Push the mode button again and record the temperature in Celsius in your lab notebook. (Note: If you push the mode again it will give you the Fahrenheit reading.)
5. Get the pH test comparator. Cut the top off of the green pH capsule (be careful as the powder will fall out) and put the powder in the left compartment. With your pipette, add water to the fill line. Put the cap on tightly and shake the solution. Let it sit for about a minute and then record your findings in your lab book.
6. Get the nitrogen test comparator. Cut the top off of the purple nitrogen capsule (be careful as the powder will fall out) and put the powder in the left compartment. With your pipette, add water to the fill line. Put the cap on tightly and shake the solution. Let it sit for about a minute and then record your findings in your
   lab book.
7. Get the potash test comparator. Cut the top off of the orange potash capsule (be careful as the powder will fall out) and put the powder in the left compartment. With your pipette, add water to the fill line. Put the cap on tightly and shake the solution. Let it sit for about a minute and then record your findings in your lab book.
8. Get the potassium test comparator. Cut the top off of the blue potassium capsule (be careful as the powder will fall out) and put the powder in the left compartment. With your pipette, add water to the fill line.
   Put the cap on tightly and shake the solution. Let it sit for about a minute and then record your findings in your lab book.

Lab Analysis

Post-lab questions

Do a Google search to find out what the optimal water quality for your water source should be. This will vary depending on the purpose of your water supply.

• What do results of the testing of pH, dissolved solids, nitrates and phosphates tell us about the health of a source?
• What ideas do you have that would help improve the quality of water for that water source location?

Research Agriculture Water Quality Management Practices

• Buffer strips
• No till
• Cover crops
• Variable application rates
  Click on the link to watch a video on how water quality is important for the applications of the vital nutrients and why farmers are working hard to help prevent any loss of nutrients to water runoff. https://h2knowlearning.org/sections/agricultural-research-and-management-practices/
• What are some of the best practices that farmers are using to help maintain the quality of our water supplies?

Take it further

Make plans to outline what you would do to help fix and/or maintain the optimal water quality for your source. Use Google Slides to create a presentation outlining your suggested plan for your water source. This is an opportunity for students to think about how they and their communities can work harder to preserve water quality.

Teacher Resources

• U.S. Department of Agriculture Water Quality
  This page provides you with various types of information covering water quality, especially as related to agriculture.
• U.S. Geological Survey How much natural water is there? 
  The page gives a breakdown of where the natural water in our world is located in cubic kilometers.
• U.S. Geological Survey How much water is there on Earth? 
  The page gives a breakdown of the amount of water in our world, the form it is in and the percentage of each form of water. In addition, it provides links to other water resources such as the water cycle and Water Basics which provides posters, quizzes and interactives related to available water in our world.
• Scientific American Fertilizer Runoff Overwhelms Streams and Rivers–Creating Vast “Dead Zones”
  This article would be a great introduction into this lesson about the concerns we face with helping to maintain water quality due to runoff.
• Farm and Dairy Understanding Stormwater Runoff
  Runoff is not exclusive to farming. This article points out several other sources of excess nutrients, and pollutants, being introduced to our streams and rivers.
• Environmental Protection Agency National Stormwater Calculator
  Short video about the sources of stormwater runoff. The stormwater calculator is a bit complicated, but interesting to look at how your school, or home, is impacting the overall stormwater runoff.
• Kahn Academy Introduction to Biogeochemical Cycles
  Kahn Academy offers many resources on the individual components such as nitrogen and phosphorus, which are fertilizer components, that cycle through the biosphere many of them through the use of water.
• United States Environmental Protection Agency Agriculture Nutrient Management and Fertilizer
  The EPA outlines various types of fertilizers and the methods in which they are regulated.
• U.S. National Library of Medicine Environmental Health Student Portal
  Many resources, videos, games and activities pertaining to water and it’s pollutants.

Reflection and Conclusion

Have students reflect on the observations they made in the lab.

• How can you play a role in preserving water quality?
• What did you learn about agriculture water quality management practices?
• What surprised you the most about your lab findings?

Science and Agriculture Careers

• Agricultural inspector
• Agricultural specialist
• Water quality specialist
• Crop production specialist

Disclaimer

Any educator electing to perform demonstrations is expected to follow NSTA Minimum Safety Practices and Regulations for Demonstrations, Experiments, and Workshops, which are available at https://static.nsta.org/pdfs/MinimumSafetyPracticesAndRegulations.pdf, as well as all school policies and rules and all state and federal laws, regulations, codes and professional standards. Educators are under a duty of care to make laboratories and demonstrations in and out of the classroom as safe as possible. If in
doubt, do not perform the demonstrations.