Due to a miscalculation, I thought I could measure the position of the Moon using the analytical balance in my chemistry class. By the time I had discovered my physics error, I already had the experiment set up and I was collecting a mass measurement every 5 seconds.
The moon's oscillatory motion didn't show up in the data, but I could tell when school was in session and (probably) when Puget Sound Energy was switching between generators. Without prior knowledge, I was able to conclude that my teacher had come in on a day off and moved around in the back storage room where the experiment was set up.
Click here for an old PowerPoint presentation explaining the results.