During the time my containers are sitting outside, I'm regularly checking them about every 6 hours to see if the level of water has changed in the containers. So far, nothing dramatic has changed enough for me to write anything, but I can see that little condensation bubbles are appearing on the inside surface of some of the plastic wrap.

In this time that I'm waiting, I've been doing some research on water evaporation to make my understanding of this experiment more clear. "Evaporation continuously moves water from the surface to the atmosphere." So in this case, because the atmosphere is blocked by a layer of different brands of cling wrap, it would change the process of evaporation.

Evaporation is when water is changed from liquid to a form of gas. This change requires heat, and is called the "latent heat of condensation". When water evaporates, it removes heat, lowering the temperature of the surface.

http://www.weatherquestions.com/What_is_evaporation.htm

The amount of water evaporated from a certain place depends on the temperature in the water and air and the humidity and velocity of the air above the surface.

Maybe.. I should have placed my containers by the window so evaporation would occur faster? But then it wouldn't really be a fair test, because they would get different amount of sunlight and each day would not have the same amount of sunlight, too. I'll just leave them where they are and see how this goes.