Intellectual Property in the 21st Century and Beyond

So it has come to my attention that there is a nagging problem that many people are ignoring when it comes to the flipped classroom; who owns the material. I have read many articles ( see article here).  So if we are creating materials as teachers to use in the classroom, then how owns them? Do schools have the right to sell the material that we have created for a profit? And if we are creating them on our own time and on our own computers, those of us who teach in an online school as well as on land school, where do we stand? Can we use materials in the classroom that we have created and then sell them on our own? Many teachers have done that in the past so why does this new video concept differ?