Science Fair Projects: How Different Waters Affect Bean Growth

Preparation and Procedure

• Obtain beans, soil, several pots or cups, measuring cups, spoons and a ruler. The containers should be of equal size and should receive the same amount of soil. The beans should be the same type. Plant two containers with beans that will only receive pure water. The role of these plants is to function as experimental controls. For the other plantings, use only one bean per container, but do two plantings per liquid.

  Place all of the beans in the same area in a sunny location. Record your daily observations in a logbook. The observations should include the date, time, temperature, the amount and composition of the liquid, and the height of the plant. Physical reactions such as color, odor, or decay should also be recorded. Do the measurements for about two months.

Sugar Solutions

• Perform an experiment to examine the effects of sugar water on plant growth. Sugar dissolves in water and won't affect pH. Create a solution with 25 to 50 grams of sugar per liter of water. Water two different plants with 21 or 22 milliliters daily. The goal is to examine if the solution prolongs the life of bean plants the same way it does Christmas trees and cut flowers. Corn syrup, or a piece of candy soaked in water, can be substituted.

Basic Solutions

• Solutions that are above a pH of 7 aren't good for bean plants. If the plants germinate, they may experience stunted growth or rapid decay or die. Basic solutions can be made with a combination of water with either baking soda or milk of magnesia. Baking soda has a pH of 8.3, while milk of magnesia has a pH of 10.5. Prepare three sets of plants. Use varying amounts of the bases, ranging from one to three teaspoons.

Acidic Solutions

• Solutions that are too acidic can cause beans to grow slowly and die. They can also prevent beans from germinating. Mild solutions won't affect the plants as much. Milk is only slightly acidic, with a pH of 6.7. Sodas contain phosphoric acid, and their average pH is 2.5. Lemon juice is more acidic, with a pH of 2.0. Create an experiment to examine the effects of acidity on bean plants.

  The experiment can be based on one product, such as lemon juice. Create different solutions that combine 10, 25 and 50 percent lemon juice with water or coke. Alternatively, water the plants with 25 percent solutions made using milk, coke and lemon, respectively. Compare the results to determine how the different products affect the plants.