This was expected to have the highest rate due to multiple factors, but no significant difference was found. Other factors that might be worth investigating might include: altitude/pressure, temperature and humidity. If the pressure or altitude were changed, it might be easier or harder for water molecules to evaporate. The temperature of the environment could be controlled to see not the effect of both light and heat but only the heat itself. Humidity, as previously mentioned, will affect the rate of diffusion since it is a concentration of water