Getting rain water.
I use an opaque, 50 gallon rain barrel from www.plastic-mart.com. I chose this model for several reasons:
-It is see-through, so the children can easily see how much water is inside.
-It is marked with gradations every five gallons to reinforce the concepts of numbers, amount, and volume.
-It has an overflow valve in the top of the lid.
-It can be adapted for a nozzle at the bottom.
-It came with the fittings to attach it to a hose that is attached to a rain gutter.
I was able to find the rain barrel of my choice from Plastic-Mart. It cost almost as much to ship as it did to purchase the item, but it was well worth it! I found a 50 gallon (with marked gradations), translucent rain barrel that I affixed a drain to for the children to use in buckets and other vessels. It also squirts excess water out the top once it's full.
In Berkeley, California our average rainfall is 25", which will result in about 3000 gallons of water being collected each year from the small roof I have mine attached to.
This is the only way I've been able to effectively teach the abstract concept of drought to preschool-age children. They can easily see if rain water has collected in the container, and if it's been used they can see that they can't have any more rain water until it rains again.
Lesson plan by Heather Taylor, firstname.lastname@example.org. You are welcome to share all materials with credit to her.