NIR Plant Stress Test: Investigating the Impact of Light and Water on Plants

Introduction (15 minutes):

• Discuss the importance of understanding plant health and the role of different wavelengths, especially NIR, in assessing vegetation.
• Explain the experimental setup and the variables being tested: water availability and light exposure.

Setup and Initial Measurements (10 minutes):

• Take initial measurements from both groups of plants

Daily Measurements (15 days):

• Perform calibration measurements each day before taking plant measurements.
• Take measurements of calibration medium (polystyrene foam) and plants from same measured height and angle.
• Water one group of plants regularly while withholding water and/or sunlight/grow light from the other group.
• Use the STELLA spectrometer to take daily measurements from both groups, controlling for variables such as angle and distance.

Data Analysis (60 minutes):

• At the end of 15 days, gather all the measurements.
• Convert measurements to reflectance before comparing.
• Use Excel to create graphs mapping out curves of reflectance for each day.

Discussion (20 minutes):

• Lead a class discussion on the observed trends in NIR reflectance over the 15-day period.
• Encourage students to analyze and interpret the data, considering the differences between the groups.

Conclusion and Reflection (10 minutes):

• Summarize key findings from the experiment.
• Discuss the implications of the results for understanding plant stress and health.
• Encourage students to reflect on the broader applications of using NIR spectroscopy in agriculture and environmental monitoring.

This classroom experiment engages students in a long-term investigation, allowing them to observe and analyze the effects of water availability and light exposure on plant health through NIR reflectance. The use of real-time measurements and data analysis in Excel enhances students’ scientific inquiry skills and critical thinking.