What's up with Waterfalls?

On a beautiful summer day I was working in my garage and Joe was standing at the end of my driveway looking down into the storm sewer. Joe is five years old and is usually very quiet. I walked down the driveway and asked him what he was looking at? He said, “I am watching the waterfall.” Just then his grandfather drove up and parked in front of Joe’s house. Joe started yelling at his grandpa not to step in the water. I am assuming that Joe said that to his grandpa because his dad told Joe not to touch the water. The reason being was because he was draining the pool and it probably had chemicals in the water. I said to Joe, “Watch this,” as I picked up a maple tree seed pod and dropped it in the water just above the storm drain. The seed pod was heading toward the waterfall when it got stuck on the storm sewer grid work, Joe was disappointed. I said, “It is hanging on by a toenail.” I gave the seed pod a little push and yelled aagghh… as the seed pod fell over the waterfall and into the river below the street, Joe thought that was great and he yelled aagghh… Then Joe found a maple seed pod and put it into the water just above the falls. We watched in anticipation as the seed pod got closer and closer to the falls, then it went over and we both yelled aagghh… Then his brother Tom came walking down his driveway barefoot and stepped into the water running down the side of the street, Joe yelled at him, “Tom, don’t touch the water”. Of course Tom didn’t listen and continued to walk in the water. Tom came over to where we were just above the waterfall. Joe picked up a maple leaf seed pod and dropped it into the water and said, “Watch this.” All three of us watched as the maple leaf seed pod headed for the falls, then it happened, the seed pod went over the falls and we all yelled aagghhh…