This is an incomplete animation of a pulser pump. I am getting there! On my computer, it is a fairly close approximation of what actually happens as the water goes down. I do not know how java works on different computers. Animated gifs seem to work quicker on a faster computer so I am not doing . Imagine lots of bubbles going down at about that rate and you get the idea.
Perhaps I am wasting time doing these animations?  These ones are done like cartoons.
If you click on the image you can go to the homeppage of the animation maker and download his beautiful animation and then make your own.