Art and Time

When I think of time-based art, I think a perfect example for me is a work a friend of mine did who was in my art class last year. Jethro got a toilet duck bottle, attached a reverse vacuum cleaner through the bottom of it, turned the vacuum cleaner on and documented the process of bubbles coming out from the top of it. He didn't intend for it to have any conceptual aspects other than commenting on time, however, you couldn't avoid noticing the sexual connotations the work had. He ended up with a series of photos showing the bubbles gradually overflowing and then stopping. Unfortunately I don't have a photo of the work but I think it would be quite easy to imagine.