Scott is scared of two things: dogs and tornadoes.
Some nights he comes downstairs from his room saying that he can't sleep because he is nervous about tornadoes. R finally decided to take him to library to learn about tornadoes, so he could eliminate some of the uncertainty.
He got two books and devoured them both. When I got home from work he summarized the things he had learned about tornadoes:
1. Most happen far away in certain US states called "Tornado Alley"
2. Most happen in the months of April-June
3. Most occur in the afternoon
4. Many are not strong enough to damage our house in a significant way
Based on these facts, he was able to deduce that the probability was essentially nil that we would get a tornado in Calgary in the middle of the night in December.
One of the books had an activity where you could make a tornado in a jar. He and Katie both got in on the action, turning one of his greatest fears into a game.
He has slept much better since.