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Effect of moisture on direction of root growth Featured science projectScience project video


This science fair project was done to determine if the direction of root growth is affected by the presence of moisture. Green beans were germinated and it was observed if the roots will grow towards the moisture.


The roots of a germinated green bean will grow towards moisture.

Scientific Terms

Hydrotropism, geotropism, photosynthesis, gravity



Hydrotropism refers to the way a plant will respond, in terms of direction of growth, towards concentrations of water in soil. It occurs when the root cap of the plant senses where the water is located and starts to grow towards that part of the soil that contains a higher concentration of water. Plants do this to avoid drought stress.

This ability of the plant’s root to seek water in soil is important because plants need water to grow and perform photosynthesis. Plants also need water to transport minerals from the soil to other parts of the plant. Without enough water, plants will wilt and dry. Prolonged deprivation of water will eventually cause the plant to die.

Studying plant growth in response to moisture is quite difficult because such tests are usually done in laboratory conditions and not in the plants natural environment. The study of hydrotropism is sometimes done together with geotropism. Geotropism is the response of the roots and the stem towards gravitational pull. Roots grow towards gravity while the stem grows away from gravity.

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Complexity level:
Project cost ($):
Time required:
5 days to prepare, 10 days for the science project experiment
Material availability:
Easily found
Safety concerns:

Basic safety requirements