series of natural disasters that most of the people sort of understood in terms of their gods and their religion. >> can we account for the plagues naturally? probably. is that the point of the story? certainly not. in the space of a year these ten disasters destroyed egypt. and that's the point. it's a miracle. miracles don't beg natural descriptions. miracles are miracles. they are when god intervenes in the order of nature. >> then god told moses to prepare the people for the coming of the tenth and worst plague. the killing of all the first-born. >> moses instructed the jews to sacrifice a lamb and to paint its blood on their doors so that the angel of death would know who was jewish and who wasn't. this is where the term "pass joer" comes from. >> and pass over that house. >> right. >> reporter: the seder is a time where jews are encouraged to ask questions. especially the children.