Has been running 85 years, it even has its own live webcam
http://www.popsci.com/science/article/2012-01/how-long-longest-running-lab-experiment
Interesting read!
Hazel, I thought that is really cool. I wonder how many other things are out there that we don't even know about hidden away in a lab somewhere?
I have this paint drying experiment you might be fascinated about.
And here I thought the longest running experiment was the Universe.
That beaker is gonna overflow!!