jodi:
And I don't have a multimeter.. unfortunately even if I had one I wouldn't know how to use it
Well that's easily fixed... Here's a simple tutorial on using the main functions of a digital multimeter. It doesn't cover everything you can use a multimeter for, of course, but it will show you how to take all the basic measurements.
Now you have no excuse! 
Edit: Adafruit has a slightly more extensive tutorial as well, if the one from Sparkfun glossed over things a bit too much.