What is the difference in the three? I have given that some thought, and this is one interpretation that seems to work.

Fantastic elements: those creations or inventions that do not exist at this time in society. In the story, all of the technological advances found in the house would seem to be elements of fantasy. The cleaning mice, the house's automated sound system, and the kitchen appliances that run themselves would all be examples. There are others, as well, in the story, including the automated and animated scenes in the nursery.

Science elements: those creations or inventions that do exist at this time in society as a result of our own scientific advancement. The most obvious element of science in the story is the nuclear explosion that has destroyed the city and vaporized the family. The red glow over the land, the heat of the explosion that burned images into the side of the house, and the radiation sickness that killed the family's dog are not products of the writer's imagination. They are scientifically sound details and part of our reality.

Vision of the future: Bradbury's cautionary tale. The story is chilling because we do have the scientific means to destroy ourselves just as the family has been destroyed and their city obliterated. Cities have already been destroyed by atomic bombs, Hiroshima and Nagasaki. This is the frightening vision of the future that develops the story's theme: "This can happen to us if we do not control our technology." 

The second vision of the future found in the story relates to the house and its technological advancements. Today, our technology is becoming so advanced, so quickly, one day we actually might have cleaning mice or their equivalent.