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


The materials required for this science fair project:

-    1 packet of green beans
-    3 gardening pots
-    Soil for the 3 pots
-    Gardening spade
-    Tap water
-    3 porous cups
-    A black marker pen


1.    For this science fair project, the independent variable is the watering method used on the 3 pots – watering from the porous cup or watering directly onto the soil. The dependent variable is the direction the roots grow in the soil. This is determined by removing the plants from the soil after 15 days and inspecting how the roots have grown. The constants (control variables) are the size of the pot, the amount of sunlight, room temperature and the amount of water added daily.

2.    Fill the3 gardening pots with equal amounts of soil. The porous cups are planted in the soil with the top of the porous cups left protruding. 10 green beans are planted in each pot. Additional beans can be placed in the pot and removed later in case some of the seeds do not germinate. The 3 pots are labeled “A”, “B” and “C”.

3.    The 3 pots are watered daily for the next 5 days and the beans are allowed to germinate. After 5 days, the porous cups in pots “A” and “B” are filled with water. The porous cup in pot “C” is not filled with water. For the next 10 days, the soil in only pots “B” and “C” will be watered daily. The soil in pot A is not watered.

4.    After 10 days, the porous cups are removed from the soil. The soil around the green bean plant roots is gently removed and it is observed to see if the roots of the plants have grown straight down or sideways towards the porous cup. The observations are recorded in the table given below.

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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