Configuring a sensor

Hello. I was a bit confused when I watched a video tutorial on youtube.

Makemagazine's fun with arduino starter kit.

A pressure sensor was connected to the ground and analog 2. I'm confused as to where the power comes from in those connections. Is 5 volts coming out of the ground, or does the analog input somehow read values below ground? Thanks in advance for the clarification.

Link please and the sensor should be connected to +5V other wise it wont work ;)

I think they're using an older version of the arduino, but they say that the pressure sensor is on ground, so I'm confused.

Without showing any code, we can only guess what the code looked light, but I'd guess that all that the LEDs were actually showing was noise on the analog pin that was influenced by the presence or absence of his finger, not the actual pressure on the sensor. They are NOT that sensitive.

Thanks. I'll remember NOT to do that when I get my arduino board. I'm just starting out, so any and all help is greatly appreciated. Thanks, again.