I'm skeptical about a some things in physics as some things are hard to understand, or I need to see proof to believe it. I find that for physics, it helps a lot to see a real life demonstration (video) of what's being explained. I understand the whole radioactive decay thing, but I have not been able to find a single video which actually shows an element decaying. Why is this? Does radioactive decay actually exist or is it a theory? Surely it cant be hard to put an element with a half life a a few days/weeks in front of a camera to show it's decay. If radioactive decay is occuring in an element, then how does the element ever actually form into a significant amount if it's constantly decaying?