Final answer:
Position yourself in an open location with a clear line of sight to all students while teaching back float outdoors, akin to staying close to the edge of the water and avoiding any spots where the view is obstructed.
Step-by-step explanation:
When teaching the back float outdoors, especially in a situation where you are responsible for maintaining visibility of other students, it is crucial to position yourself strategically. First, ensure that you choose an open location with a clear line of sight to all students. You should be positioned in a way that allows you to see every student easily, avoiding any blind spots. The positioning advice from this context is somewhat similar to the military strategy of occupying the sunny side of a hill mentioned in the provided text, although not for the same reasons.
While instructing one student in the back float, try to stay close to the side of the pool, river, or lake so you can easily scan the environment without turning your back on the class. It's important to ensure that there are no tripping hazards or chances for students to collide with each other or fall over any rolling balls or other equipment in the area. Similarly, much like the explanation of the eyes in classroom settings adapting to focus from near to far objects, you as an instructor need to continually shift your focus between the student receiving direct instruction and the rest of the class.