This week, the Ghost Hunters visited the Philadelphia Zoo. Whenever TAPS hits Philly, I get mixed feelings. See, I went to college in Philadelphia and have many fond memories of the city. Yet the only place they've ever shown that I recognize is a cheesesteak place on South Street. I guess I'll have to wait until they stop visiting historical sites and start hunting in sleazy college bars.

The most dramatic "finding" was a mysteriously falling FLIR camera. While Jay and Grant were investigating the attic of Solitude House, Jay went upstairs to investigate while Grant stayed down below. As soon as I saw them separate, I wondered if something was going to happen. As we've been pointing out here for some time, things tend to move on their own around Grant when no one can see him. My anticipation was rewarded pretty quickly. Grant put the FLIR on the stairs two steps up. While Jay was upstairs, the camera (according to Grant) fell on its own and rolled down two steps. Of course, this could be accidental. This would mean that Grant is unable to tell the normal action of gravity from the work of a ghost.

Nearly everyone seemed to be reverting to form in this episode. Britt and K. J. once again chased a spirit conveniently invisible to the cameras that enjoyed peering around corners. I suspect that they might be sincere, but I also suspect that their eyes are playing tricks on them. Kris Williams felt a mysterious touch on her head, but failed to notice the bug crawling on her chest moments before. Were these related, or did she just brush her hair against the ceiling? At least Amy entertained us with a tap-dance routine while trying to create footsteps for Kris to listen to.

There were also some slamming doors. Have you ever noticed how ghosts on Ghost Hunters seem to have fads? In earlier seasons, ghosts apparently liked to lead Jay and Grant on chases through long corridors. Then, for a while, ghosts were murmuring to them in tinny-sounding voices. Nowadays they like to slam doors when no one is looking. At least one of these doors was actually in full view of a camera, so I thought, perhaps, they would show us this door opening and closing by itself, or otherwise admit that it wasn't that particular door. Instead, they merely said in the reveal that the DVR showed no one nearby. Nice to know, but what I wanted to know was, "Did the door open?!" Doors staying closed without anyone nearby is hardly paranormal, and sounds by themselves don't impress me much. I suspect that we will continue to hear the sounds of mysteriously slamming doors for at least a few more episodes, though.

I did discover something interesting, at least to me. Apparently, a zoo board member once saw a strange, misty figure in the tunnel under the Solitude House. Doing some basic digging around, I learned that the tunnel is forty-five feet long. That's interesting, because one of the resonant frequencies for a forty-five foot tunnel would be around 18 Hz, which is supposed to be approximately the resonant frequency of the human eye. One of my favorite paranormal researchers, Vic Tandy, suggested that vibrations around 18 Hz could rattle the jelly in our eyes and cause hallucinations of grey, misty shapes. Now, this is a back-of-the-envelope calculation based on a figure I read in a newspaper article, and I've never seen the 18Hz hallucination effect validated. Still, it would have been a very interesting thing to investigate! It's interesting that Jay and Grant heard something that sounded like singing or music while they were investigating down below. Tunnel resonance might be to blame there, as well.

Since TAPS has upgraded their recorders from the old digital dictaphones to higher-quality Zoom recorders, the EVPs have been correspondingly less convincing. During the reveal, Grant plays several supposed EVPs. Dr. Andrew Baker, the zoo's chief operating officer, gamely tries to go along with them, but calls one of the EVPs a mechanical sound. It sounds like a random rattle to me, too. Grant just grins, plays the sound again, and says, "Hear the whisper? It's right in time with the mechanical sound." Now that's chutzpah.

Discuss the episode in the forums.