Woops. I just realised I made two mistakes in my experiment.

1. I had initially forgot to label my containers with which plastic wrap was on which container, and when I had gotten around to doing it I have a feeling I got confused with a few of them and labelled them wrongly.

2. I found a little crack in one of my containers.

Guess that didn't go well. I'm starting it up again soon, and this time I hope I remember eveything I forgot.

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.

Over the weekend, I bought 4 different types of cling wrap and decided to start up my experiment. I put 250mL of water into 5 take away containers and sealed it over with the different types of cling wrap, all cut into 30cmx30xm squares. I didn't put any plastic or covering over the last container because I wanted to use it as a comparison to all the other ones after the experiment.

I placed all the containers in a place where the room temperature was pretty constant, so it would be a pretty fair experiment. Today is my second day in waiting, and after a few more days I'm going to take the cling wrap off and see which container holds the least/most water.