Cheap Solar Fridge

This instructable is being entered in the Green Tech Contest so please vote.

This solar fridge is a simple and quick diy project. The reason I decided to build it was because the fridge in your house takes up a ton of energy.  This fridge is so cheap and reliable that it can be used in 3rd world countries.  It takes about 15 to 30 minutes to complete and it only cost around $15 dollars.  

Here is what you need

1 large clay flower pot
1 small clay flower pot
 sand  (I used about 1/4 of a bag) 
 towel 
 water
 clay or plumbers putty   (only needed if there is a whole in the bottom of the pot)   

The first step is to see if you have a hole at the bottom of your pot.  If there is not a hole then you can skip this step.  If there is a hole then take your clay or putty and firmly press it into the hole and cover it.  Make sure there is no gaps for water to leak out.

Fill the larger pot with a layer of sand.  Then put the smaller pot inside the larger one and level the sand until both pots are at even height.

Fill the remaining area between the pots with sand.

Pour water into sand to saturate it completely.  Once the water begins welling up instead of soaking in, you can stop.

put any items you want into the fridge.

Now you have to soak the towel and place it over the top of the pots. 

Make  sure you put your fridge in a shaded place.  Also return once or twice a day and refill the sand with water and dampen the towel.

The action that allows it to stay cool is the evaporation of the water surrounding the smaller pot.  As the water evaporates, heat draws out from the smaller pot, keeping the contents inside much cooler the the surrounding environment.