An interesting science project idea comes from One Stop Candle, a website dedicated to all things related to candles and candle-making. Does the color of a candle's wax affect the rate at which it burns? To control the experiment, the candles should come from the same manufacturer, should be equal in size and shape and must not be color-dipped. (Color-dipped candles are white candles dipped in color; the color is not in the wax.)
Get three white and three colored candles. Weigh them on an extremely accurate scale set to measure weights as low as 0.1 gram. Record the results.
Burn each candle individually, as the flame from a nearby candle could affect the results. Burn them in an aquarium to control the ambient temperature and other factors, such as wind, that might affect the burn rate. Set a timer and allow each candle to burn a specified time. Weigh them after burning and record the results.