Science project

Effects of Acid Rain on Plant Growth

Difficulty of Project


Cost (Approximate Cost of completing the project)

Less than $20

Safety Issues


Material Availability


Approximate Time Required to Complete the Project

Two weeks


To understand the effects of acid rain on plant growth over the short term and extrapolate the results to better understand the effects of acid rain at larger scales.  


  • 2 plant pots
  • Enough potting soil (or garden soil) for each pot
  • One package of plant seeds (Sunflower seeds work well)
  • 2 spray bottles
  • Lemon juice
  • Direct light source
  • Permanent marker 


Acid rain occurs when low pH acids pollute our air and are deposited back on earth’s surfaces when it rains, snows, sleets or hails. These gases convert back to acids when they contact water. Acid rain can be a problem when environments lack strong bases to neutralize the acidity.  

Research Questions
  1. Are your results what you expected? Why do you think this occurred?
  2. What implications does your experiment have for the effects of acid rain in your community?
  3. Given your results, what environments or areas do you think would be particularly vulnerable to the effects of acid rain?
Terms, Concepts and Questions to Start Background Research
Acid rain
Sulfur dioxide
Nitrogen oxide 

Experimental Procedure

  1. Fill each pot with potting soil. Place several seeds in soil – reading the instructions for planting each. (You may want to begin with three pots in case the seeds in one do not take.)
  2. With a permanent marker label one pot ‘Acid rain’ and the other pot ‘Normal’.
  3. Water both pots and place them under a direct source of light.
  4. Repeat watering every day or every other day (depending on seed type) until each pot has a sprout with leaves.
  5. Measure the height of your plants and record this data as Day 1. (Tip: Take photographs throughout to use in your presentation and analysis.)
  6. Fill both spray bottles with water. Select one spray bottle and add lemon juice at a quantity equal to 5 drops of lemon juice per one liter of water.
  7. From this point forward, water each plant as usual and then spray each plant with the acid mix or normal water as labeled. (Be sure to water the plant first and then spray the acid so as not to wash the acid off of the plant.) Follow this by measuring the plant every day.
  8. At the end of 14 days you should have sprayed the plants and measured their height every day (or every other day).
  9. Examine the growth in each of your treatments.  


U.S. Environmental Protection Agency
Think Quest
Environment Canada

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