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Effect of water hardness on seed germinationFeatured science projectScience project video


The materials required for this science fair project:
- 1 packet of black-eyed Susan seeds (minimum 60 seeds)
- 3 large beakers
- 3 balls of cotton, enough to fill the above beaker
- 10ml of water softener
- 5 mg of calcium
- tap water
- 1 measuring cylinder
- 1 black marker pen


1. For this science fair project, the independent variable is the hardness of the water – hard water, tap water, soft water. The dependent variable is the number of seeds that germinate. This is determined by observing the seeds every day. The constants (control variables) are the environment the plants are kept in (temperature, humidity, light, etc), the type of plant used, the amount of water used and the size of the container.

2. The 3 beakers are labeled as “Hard”, “Tap” and “Soft”. One ball of cotton is placed inside each of the beakers. The packet of black-eyed Susan seeds is opened and 20 seeds are placed on the cotton in each of the beakers. The seeds are arranged so that they are at least 5mm away from each another.

3. Using the measuring cylinder, 200ml of tap water is poured into the beaker labeled “Tap”.

4. The 5 mg of Calcium is mixed with 200ml of tap water and poured into the beaker labeled “Hard”.

5. 10 ml of water softener is mixed with 200ml  of tap water and poured into the beaker labeled “Soft”.

6. The number of seeds germinating in the 3 beakers is observed for the next 5 days and recorded in the table given below.


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

Basic safety requirements