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Effect of acid rain on sunflower growthFeatured science projectScience project video


This science fair project was conducted to find out how acid rain affects the growth of sunflower plants. The science fair project was carried out by watering the plants with water of different pH levels.


Sunflower plants will grow best at pH levels between 5.5- 7.5.

Scientific Terms

Nitrogen, sulphur dioxide, water vapor, sulpheric acid, nitric acid


Acid rain and plant growth

The release of nitrogen and sulphur dioxide by factories and vehicles is one of the main causes of acid rain. These gases combine with water vapor in the sky and turn into sulfuric and nitric acid. They are then returned to the surface during rainfall. Because of the low pH level of this rain water, it is called acid rain.

Acid rain does not fall at the place where the water vapor that forms the acid rain the first place, was released into the atmosphere. The water vapor may travel over long distances for days or weeks, depending on the direction and intensity of the wind, and finally fall somewhere far away, perhaps in a neighboring country! Rain water normally has a pH of around 6.0. However acid rain is able to reach a pH of between 4.0 and 5.5.

Acid rain has serious effects on plants and vegetables. Acid rain can damage a plants’ roots, cause stunted growth and even kill the plants. Nutrients in soil are destroyed and the micro-organisms that help produce these nutrients are killed by acid rain. The plants that survive are usually very weak and vulnerable.

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Complexity level:
Project cost ($):
Time required:
1 day to prepare, 14 days for the science project experiment
Material availability:
Easily found
Safety concerns:

Handle acid with care – use protective clothing/goggles.