Teacher:Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
Teacher: Now, understand the problem? Solve this instance: Because of the wave character of matter, the idea of well-defined orbits gives way to a model in which there is a cloud of probability.
Student:
Because of the wave character of matter, the idea of well-defined orbits gives way to a model in which there is a cloud of what?