Screen brightness and battery power

[yg17]

I use my Powerbook (15", rev before the last PPC revision) in class, and need it for a good 4 hours or so during the day. To acheive that, I turn my brightness way down as to not drain the battery. Usually by the time I get done with my last class, I'm down to 10-15% charge. Problem is, I can hardly see the screen. How much of an effect does brightness have on battery power? If I turn up the brightness, will it use a significant more amount of power? I do turn of Bluetooth to save battery, but turning off Airport isn't an option....need something to do during those boring lectures Thanks.

And on an unrelated note, someone sitting near me just pulled out his Alienware laptop....that thing is about as thick as 2 of my PowerBooks put together! Probably cost him the same as 2 PowerBooks too.

 

[Applespider]

The brightness does make quite a bit of a difference but you could always try bumping it up a little if you end up in very bright rooms and see how much faster you run out; or try to sit in dark corners so that it seems brighter.

You can't turn the Airport off for the interesting portions of the lectures?

Alternatively, buy an extra battery so that you can swap them in/out half way through the day