Well, I'm sure most of you have heard the expression "curiousity kills the cat". Well, curiousity is gonna kill the Sean someday! I am always doing things in different ways.

Well, I got one. What would happen in you hooked a 9 volt battery to the pins of a fluorescent tube. THEY GLOW! I tried it on an F15T8 tube. It may not seem like a big deal, but it looks like a tube stuck on a preheat fixture (starter stuck). It looks pretty cool, but I didn't do it for anymore than 2-3 seconds, because I was afraid it would explode (the tube). Do you guys think it would explode?

I would like to know if any of you have done silly things like this, or tricks on lighting. I know I've power a CFL/Tube with static, and a 'van-de-graph' generator before, which was cool.

9 volt battery wouldn't hurt that tube.  The electrodes have about 9-11 volts across them during preheating.  If the current got too high, the electrodes would burn out before anything else.

My guess the 9V battery would be empty before really something happen.
And electrodes itself would survive such heating for pretty long time...

What's happening there is that you're striking a discharge across the length of the heater filament.

The 9V DC supplied by the battery provides the electrode heating just as when used normally in a preheat fixture.  This causes enough thermionic emission from the electrode surface that the potential difference across the filament itself is sufficient to produce an arc across the electrodes.  This has a lower resistance than the filament, so becomes the preferred current path. 

Thanks to the negative resistance characteristic of an electrical arc (the more current that flows through it, the hotter it gets, and the lower its resistance gets) means that the only thing limiting the current there is a combination of the electrode structure and the 9V battery's internal resistance.

Depending on the type of tube and the normal heater current, one of two things will likely happen if you were to keep the battery connected, and one of these is that it will simply go flat in pretty short order, or worst case, the electrode would go open-circuit.

Quite a few F4T5 tubes met that fate at my hands when I was a youngster!

@Zelandeth:
The 9V is not sufficient to cause an arc, as the cathode fall (potential difference necessary to free-up an electron even from the hot cathode; in cold state it goes to 100's of V) on most high current intensity cathodes (so those used for lighting) it is above 9V (for hot cathode lamps it is calculated at about 15V).

But from my childhood i remember seeing a lamp of about F4T5 size rated as 4W using exactly this concept to operate from 13V vehicle power.
It was really using axial filament, one contact on each end and it emitted quite lot of cool-white light for it's 4W power rating (really comparable to inverter based F4T5 fixtures), so it was for sure not an incandescent based source.
I think it would be prominent collection piece, but it was not mine and i have no clue where it ended, at that time it was already very old piece of "garbage" accumulated by my chool-mate's father over the years in his garage...

Hmm, interesting one Medved.  I realise that the striking voltage (even for the 7-10mm gap) would be far and above the 9V or so available when cold, I would have thought that would have dropped considerably when running in hot cathode mode. 

I remember that testing this with the old T4 lamps, that the resulting light was the very cold blueish white (most of these lamps were "daylight" white), nothing like incandescent, and there was a very distinct point where the glow changed from yellow/orange straight to bright blueish white.  The only behaviour I could attribute that to was the formation of an arc across the contacts.

From what I've read, about 10V is needed to get an arc across "good" fluorescent electrodes - so our little 9V battery does seem a bit weedy for the task.  I'm wondering now whether I was using something else as a power supply - problem here is that I'm pulling data from 15+ year old memories!