Motion sickness happens when your body is feeling the sensation of movement. This can happen when you are riding in a school bus, sailing on a boat, or riding in the backseat of a car. When you are reading a book, your eyes do not see the movement, which confuses your brain and causes some people to feel sick. If you get car sick, the solution is to look out the window, not down at your book, so your brain and body will be in sync.