ISO...I don't know

So I was supposed to play around with shutter speeds and apertures this week, but again because I don't have a DSLR camera I couldn't really do this. However, I was able to at least learn what these meant (shutter speed is how fast the picture is taken and relates to how much light is let in...obviously, and aperture is umm... well...I think it's how blurry the background is).  Anyways, I'm going to visit my sister in a few weeks and she has a DSLR so hopefully she'll let me borrow it for an afternoon and I can post some pictures of what this actually all means.  (Erin if your reading this...please :) )

Good news is that I got to fiddle around with the ISO...the bad news is that I don't really understand what ISO is.  I think basically it means that it controls how much light gets into your camera.  If it's low not as much light gets in, if it's higher than more light gets into the photo but the picture quality isn't as good.  I got this info from http://my3boybarians.com/2010/10/controlling-the-faucet-learning-iso-day-4/ which is a great website if you don't know anything about photography.  Anyways...enough about the technical stuff...onto the photos!
                                                 

                                                     ISO 100

                                                     ISO 200

                                                    ISO 400

                                                     ISO 800

                                                    ISO 1600

                                                    ISO 3200

Not much of a difference in beginning, right?  But later on you can see how the light affects the picture.  I took my son with me that day and I could resist taking some pictures of him either.