Hello, could someone tell me what is the main difference between effects of diffraction and interference? For now, I think that diffraction is name for deviation of waves when they come to obstacle. And interference is phenomenon when two or more waves are in superposition in some point in space. But the main thing that I do not understand is the difference between diffraction and interference picture. I simply think that those two are the same, because, first wave has to do diffraction on some obstacle and after that to interferes with itself. Thanks!!!