There is no excuse for your principal. However,the science teacher was likely not privy to all the documentations supporting the IEP. What I have found extremely helpful for my Special Needs child was to send a very detailed email to each teacher at the beginning of each year presenting the medical diagnosis, the practical manifestations of his medical issues and the specific concerns in the classroom, my offer to support the teachers and an open invitation to contact me with any problems. I have had many teachers thank me for helpful information that they would not have otherwise received.