Hydroponic Nutrient Solution

A Carolina EssentialsTM Investigation

Total Time: see below

Prep: 30 mins | Activity: Experimental Design: 1 class period plus the evening Experiment Setup: 30 min on day 2 Daily Experimental Measurements and Observations: 10 min (duration to be set by teacher) Concluding Results and Class Discussion: 45 min

Life Science

9-12

High School

Overview

This student-designed investigation is an extension for the Visual Desktop Hydroponics Kit. In this kit, students investigate the phenomena of plant growth, from seed to mature plant, using a hydroponic growing system. After a structured investigation of a hydroponic technology, students will design an experiment to test different nutrient solutions. Class data is compiled and analyzed to obtain results. Any hydroponic growing system can be used to complete the investigation. Students should be familiar with hydroponics before beginning the investigation.

Essential Question

What nutrients are necessary for plant growth?

Investigation Objective

  1. Design and carry out an investigation to test the quality of hydroponic nutrient solutions.

Next Generation Science Standards* (NGSS)

HS-LS1-6. Construct and revise an explanation based on valid and reliable evidence for how carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules.

SCIENCE & ENGINEERING PRACTICES

Planning and Carrying Out Investigations

DISCIPLINARY CORE IDEA

LS1.C: Organization for Matter and Energy Flow in Organisms

CROSSCUTTING CONCEPTS

Energy and Matter

Materials

Safety & Disposal

Use this kit only in accordance with established laboratory safety practices, including appropriate personal protective equipment (PPE) such as gloves, chemical splash goggles, and lab coats or aprons. Ensure that students understand and adhere to these practices. Know and follow all federal, state, and local regulations as well as school district guidelines for the disposal of laboratory wastes. Students should not eat, drink, or chew gum in the lab and should wash their hands upon entering and before exiting the lab.

 

The rock wool used in the Visual Desktop Hydroponics Kit is made from rock and potash. It can be a skin, eye, and respiratory irritant. When handling rock wool, avoid getting the material near the face. Use gloves to avoid potential skin irritation, and wash hands thoroughly after handling the material.

Preparation

  1. Set up the Visual Desktop Hydroponic Kits or other hydroponics kits as directed.
  2. Place each hydroponics unit under a light bank.
  3. Do NOT fill the units with nutrient solution until students have had a chance to design their experiment and have it approved. Students cannot test more nutrient solutions than there are hydroponic units.
  4. Remind students to consider a control solution. Distilled or deionized water can serve as a control nutrient solution. Tap water, bottled water, or well water may contain minerals.

STUDENT PROCEDURES

  1. Brainstorm ideas for a testable question to investigate the effect of a hydroponic nutrient solution on plant growth. Write the ideas down.
  2. Complete background research on hydroponic nutrient solutions and water-soluble fertilizers. Attach the research notes to the lab report.
  3. Select the idea to test and rewrite the idea in question format. The question should include the topic and variables to be tested.
  4. Identify the variables: independent (include a control group), dependent, and controlled. You are limited by the number of available hydroponic kits.
  5. Write a step-by-step procedure.
  6. Make a materials list.
  7. Create a data table.
  8. Describe how you will analyze the data.
     
  9. Get approval from the teacher.
  10. Conduct the experiment.
  11. Analyze the data.
  12. Make an evidence-based claim.
  13. Write a formal lab report.
  14. Share the results with the class.

TEACHER PREPARATION AND TIPS

    1. Brainstorming can be done as a class or group discussion. You may want to limit the possible ideas to a few choices based on the available materials.
    2. You may decide on 1 or 2 questions for the entire class to investigate so there is ample data to analyze.
    3. Remind students that they need a control group. 
    4. Check this carefully to make sure the procedure is doable.
    5. Make sure all materials are readily available.
    6. Check and initial each student, group, or class design.
    7. Individuals, groups, or the class may analyze data. Analysis should include group averages and graphing at minimum. If the sample size is large enough, descriptive statistics can be added. If the whole class is contributing data, keep a digital spread sheet and complete the analysis together.
    8. After students share results, hold a class discussion addressing the results, problems with the experimental design, and any changes that should be made.
  1.  

Data and Observations

Students may choose to measure variables like plant height, root length, mass of the plant with the pot after draining for a period of time, number of leaves, or days to sprout. Emphasize consistency in measurement and always use the same tool. All data should be in table format with variable names and units of measure included.

Analysis & Discussion

  1. At a minimum, students should graph the data and calculate averages for each group.
    Additional statistical analysis should be directed by the teacher.

    For reference:
    Aqua Vega NPK = 5-3-10

    Trace elements include calcium (Ca), manganese (Mg), sulfur (S), iron (Fe), manganese (Mn), zinc (Zn), boron (B), copper (Cu), and molybdenum (Mo).

    Miracle-Gro NPK = 24-8-16

    Trace elements include boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn).

*Next Generation Science Standards® is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, these products.