I Can Teach My Child posted a fun little sponge activity to do that we tried out today. My boys had a great time with it. We filled up a bowl with 8 cups of water than put it outside and put a bowl on the other side of the yard. The idea is to have your child move the water with sponges. I had all three of my boys going at one time.
After they had emptied the first bowl we measured how much water was in the second bowl. Then we talked about ways we could have lost water (dripping from one bowl to another and so forth). After doing that two times I timed how fast they could do it. We noticed that when they were trying to go fast they didn't get as much water into the second bowl. They did this three times, then I went ahead and did it and tried to show them how to move fast and still save as much water as possible. They had fun cheering me on.