Good science fair projects must be measurable. Your topic should ask a question that you can test, which enables you to research the topic and formulate an informed hypothesis regarding the outcome you expect. You can then design and conduct your experiment, collecting and measuring data based upon which you draw conclusions.

Test the impact of liquids other than water on plant growth. Design your experiment based on feeding one plant with water, another with milk, a third with orange juice and a final pot with vinegar. Be sure all other conditions, such as exposure to sun, are consistent with all four pots. Record each plant’s growth daily using both a ruler as well as a digital camera to store evidence of your experiment and the results. Add other liquids to expand your experiment. For example, test the results of flavored water or soda on plant growth.

Test the duration of AA battery types. Purchase two sets of brand new AA standard batteries, heavy duty batteries, alkaline batteries and rechargeable batteries with a charger. Set a battery-operated clock to 12:00. Put each set of batteries into the clock, and record the time the clock stops, which will tell you how long that particular type of battery lasted. Test the same type of battery in the clock again, and average the time of both trials. Repeat this procedure with each type of battery. Test the batteries in other devices to ensure results are consistent across the board.

Test both organic and inorganic fertilizer on the growth of grass. Purchase six peat cups from your local greenhouse. Fill each pot with the same soil and same amount of grass seed. Fertilize three with organic fertilizer and the remaining three with inorganic fertilizer. Water each cup with the same amount of water every other day. Add more fertilizer once a week. Measure the growth of the grass every three days over a three-week period. Determine which fertilizer, organic or inorganic, facilitates the fastest grass growth.