I LOVE PHOTOGRAPHY!!!!

I love my photography class! I have only been to two classes so far but have already learned alot about my camera that I didn't know before. I learned about controling the lighting in your camera yesterday. I found out how to change the white balance, the f stop the shutter speed and the ISO. Still not exactly sure what the ISO does despite many explinations of what it is but if any of you know what it is and would like to take a shot at getting it to click with me I would greatly appreciate it. So far the only thing I have noticed about it was that when the ISO was really low, my pictures were black outside, but when it was high I had more clarity. Some thing I know about it are 1. I know it has something to do with lighting since that was our focus yesterday, and 2. dad said that it had something to do with shutter speed and video but I didn't really understand what he was trying to explain. Other than that I am clueless. I can't wait to find out what we get to learn about next class. I am really enjoying experimenting with the f-stop, and the shutter speed and know I would enjoy experimenting with the ISO a lot more if I could just understand what it is for. I have loved the homework so far, after all what homework could be better than taking photos? I will post some of the photos I have taken for the class later.