I’ve seen the movie National Treasure a couple of times (and it was on again recently) and while I enjoyed it, there are a few things that bugged me about it. Two physics-related, and one, not so much.

1. Why use a green laser to set off the temperature sensor alarm? Green is easy to see, and could have been noticed by anyone in the room. What would have been better is an infrared laser of the same power — the heating would have been pretty much identical. But since Riley was looking through the viewfinder of his camcorder, he would have been able to see an IR beam! Camcorders filter IR for the recorded signal, but tend not to do so for the signal going to the viewer. You can try this with a TV remote, and see it flash in the viewfinder of your camcorder or digital camera. So he could have heated the detector with a much lower risk of detection. Riley’s a techno-geek, so he should have known this.

2. They lucked out with the shadow of the steeple of Independence Hall. The sun’s relative location in the sky varies with the time of year, both vertically and horizontally, due to the tilt and orbit of the earth. This means the shadow would have traced out an analemma, which I have previously discussed. That the shadow pointed to the correct brick was fortuitous. There should have been some clue in there about time of year, and some mention of how to correct for that.

3. Jon Voight being so pissed off. His “all it will do is lead to another clue” anger would have been more believable to me if anyone in the family had ever figured out a clue before, and especially if he had failed to solve a riddle where others in the family had succeeded. As it sits, though, it only made sense for him to think the first clue was a fake. But once it was solved, he was proven wrong.