Test the center of gravity with balancing butterflies. Use a butterfly stencil or shape made of construction paper 4 inches wide and 2 inches tall. Glue two counter weights on the underside of each wing, such as pennies, dimes, washers or buttons. Make sure to use two equal weights or the center of balance will be thrown off. Place the tip of the butterfly head on your index finger, to perform this balancing experiment. Adjust the weight size and position of the butterfly if it does not balance on your finger.
Test why some soft drink cans float while others sink. Place several brands of unopened soft drinks in a sink or water basin that is 75 percent filled with water and document your findings. Make sure there are no air bubbles caught under the bottom of any of the cans, and that you have regular and diet soft drinks. Sugar is denser then the artificial flavoring used in diet drinks, affecting its floating capabilities.
Test which over-the-counter pain medication dissolves more quickly, allowing you to see which pill will works fastest. Buy at least three types of painkillers, such as aspirin or acetominophen. Fill three cups with water, 75 percent in each. Drop the first pain reliever into a glass and use a stopwatch to calculate the amount of time it takes the pill to dissolve and record your findings. Repeat this process with the other pill brands, documenting your findings in a chart. Make sure to test each pain reliever more than once, ensuring your results are accurate.
Test which light bulb wattage causes water to evaporate the quickest. Build several boxes with the same dimensions, installing a light bulb fixture with different wattage specifications in each. Place a container filled with the same amount of water in each box. In one box, place only a container of water, excluding the light bulb fixture, representing your control variable. Expose each container to the light test for a specific period of time. Measure the water levels after the time has expired and document your results.